I have searched you tube extensively and there has been no video this so in depth on fuses for solar system. So this in my opinion is a diamond in the rough video. Being said 2yrs old I know there are better fuses on the market that will do better. BUT key point is , the explanations you have are solid and sound. This video brought me into the light of what I was seeking. Thank You
thanks a lot @modwrath810 for the feedback. super motivating. I will also do a similar updated video about this topic, hopefully soon ;) - cheers, Lupo
Never use non-branded fuses and breakers. The DC breaker you showed will likely not function well. They are commonly misrated, and the terminals are too small for the lugs. Great explanation on fusing the solar panel. The DC breaker from the solar panels is not there to protect the wire. It's to provide a mandatory shut off. The wire will be rated higher than 10A, so if a current from the panels is high, it won't melt the cable because it cannot get that high.
thanks @cleversolarpower, you are right. especially the cheap ones won't work very well and trip earlier. the design itself is ok and there are also good ones out there but as always, if you buy very cheap stuff you will also get bad quality. cheers, Lupo
Always use a DC breaker (like the cream colored shown) on PV system! If you have an array in series, many mpp systems run 250 to 400 volts so make sure the breaker is rated in excess. Pay attention to the polarity markings on the breaker or the breaker may be destroyed and catch fire. The black DC breakers are for battery voltages only and stay away from the no-name type shown. Use Buss or Bluesea brands.
thanks Karl for the information. Fully agree, the proper double pole breakers are preferred and if you want to avoid problem, go for a proper brand. I also show the problem of those breakers in ruclips.net/video/H5jYRlLm_VI/видео.html cheers, Lupo
For large loads like pumps, relays are useful and give you more flexibility than use high amperage switches as you can neatly mount all the switches in a main panel.
thanks, that's a good suggestion, as you have a clean panel, you can use the same smaller switches and wiring gets also easier. the downside is that you need power for the relais but usually this shouldn't be a huge problem. cheers
That connection from the controller to the fuse box is kind of weird. It would make more sense to connect the fuse box to the voltage coming the battery.
thanks Peter, you are right, in general, it makes sense to connect the load to the battery directly. some charge controllers such as my victron have an output for the load. because of that they can measure the consumed energy and also provide a low voltage cut off. add this output is limited, you can't connect high load such as inverters but for lights etc it is fine. cheers, Lupo
Thanks for the video. It is very educational. I like the way you explain things, which helps absolute beginners like me. I know the video is about a year old but I am wondering if you could explain a bit more, the protections needed between the battery and the controller. I understand the concept of breaker, which also helps to disconnect the battery power source, but I think you also suggest that the controller also needs protecting, so I don't quite understand that bit. The question is, shouldn't the breaker close to the battery, also protect the controller? And why is an additional fuse needed between the controller and battery breaker, to protect the controller (around 8:20)? I hope my question makes sense. In your example circuit, you have different segments, e.g. PV to Controller, Controller to Battery, Controller to devices/loads via FuseBox, etc. Are you able to advise what type of cable grade is needed/appropriate for each segment in order to avoid the cable melting and potentially catching fire? Thanks.
Hey! thanks for your question. It is a bit misleading because I didn't draw the heavy load like an inverter. This inverter would be connected to the big breaker (e.g. 100A). The additional breaker in front of the controller is to secure the controller (e.g. 20A depending on the controller). That is why I have two breakers in series. A 100A breaker as close as possible to the battery wouldn't protect the controller in case of a faulty circuit because the controller can just handle 20A. Therefore it is good to add another fuse between big main battery fuse and controller. I hope that helped. Regarding the cables you just have to know what the max current is in the respective circuit and then use one of the tables (just google for "wire size amp ratings"). cheers, Lupo
Is it going to work and safe to use a circuit breaker just as a power shut off switch to your solar system from the solar panel lead ins? The reason I ask this is that I found many solar charge controllers do not shut off properly when the batteries get full capacity. I had a solar charge controller melt recently from this and overcharging when it SHOULD have shut off but didn't. But then I found out other solar charge controllers also are not shutting off right. I don't see very many people talking about failures of charge controllers to shut off right also. And it doesn't work to always get the most expensive charge controller out there when you have a budget. So I want to have an off and on switch for when I'm not around. I don't want to take any more chances of not having a shut off, but I don't want to use the plugins for the pv wire connectors themselves as the switch since it would put wear on them.
Hey, Fred. In general I like to try out things, also cheap stuff from chinese, but you have to know what you buy and that you have to test it. sometimes it is crap, sometimes it is good. If you want to be on the safe side I would buy certifies breakers (e.g. UL in US or DIN in Europe). So far I haven't got really bad stuff from aliexpress, but just recently I found out that the 100A breaker trips already at around 60A ... that can happen, but the breakers usually work well but I can't recommend it for a bigger system which should be also safe and where you have to rely on those breakers. cheers, Lupo
@@LupoDIY I am preparing to go off grid, I have built the shad, run cables from field to house, installed frames on field... bought circuit breakers and conduits,. Is a big project (60kw of storage lipo4) still in progress... the circuit breakers I choose (same as you) seemed the best choice ,but haven't tested yet.
hey @ksolar1062 thanks for the question. I do not see a problem there, you can also connect the controller to the PV without having a battery connected. usually controllers can handle this situation or why do you think it is a problem? cheers, Lupo
I'm a little confused because first you said that you didn't need a fuse breaker between your solar panel and the charge controller because of the low amperage of the panel, but later on you contradict that by saying that a 10A breaker would be necessary to protect voltage going to the solar panel. Can you please explain this discrepancy? Thanks.
Hey @truthbknwn, thanks for the question. This is correct, you do not need a fuse as my single solar panel can't produce more than 10amps which is fine for the cables. The problem is the power source on the other side. In case of a faulty controller it might be possible to short the PV and the battery which would lead to a high amp flow. Therefore it is always good to have a fuse between the battery and the controller/PV. I put a breaker between the PV and the controller just to have a switch in between and be on the safe side. Hope that helps? cheers, Lupo
Hey Taras, thanks for the question. Sry, I didn't draw another load, the inverter, which is connected to the 80A fuse - it is mainly to protect the circuit connected to heavy load like an inverter. cheers, Lupo
good catch @Jxsanc123 - I didn't explain it in detail but my charge controller has also a connection for load which can be switched off automatically by the charge controller in case the battery soc is too low. cheers, Lupo
in addition, the MPPT "load" on that model allows the PV to power your loads directly not taking it away from battery unless voltage drops and batt takes over
Your solar panel has a maximum or short circuit current, which is OK to draw, so there is no reason to fuse that. Unless you place multiple panels in parallel.
hey Aliza, thanks for the feedback. you are right, it is not needed but it is very convenient to have a breaker two break the connection to the panel. and in theory there could be also current flowing from the battery into the solar system in case of a fault. cheers, Lupo
it depends on the system. usually the have fuses inside. but it is always good to protect your cables by additional fuses. They can also be used as switches which might also come in handy. cheers, Lupo
I place a circuit breaker in line with anything that is connected to the DC power bus. This offers protection and a means of disconnecting (or isolating) any circuit tied to the bus. That white circuit breaker is a DC magnetic and thermal type, which must be wired in the correct polarity, otherwise the breaker will catch on fire during an overload. The black circuit breaker you show is a thermal breaker made for 24 volts DC maximum. This is a low cost type, likely manufactured in China. I have had so much trouble with these Chinese breakers, I test each one with a calibrated DC current to determine the trip point, as they have a huge tolerance. For the 100 amp type, I have measured trip points from 20 to 70 amps. The fuses you show have a maximum voltage rating of 24 volts DC. You cannot use AC rated switches for DC due to the 10X open circuit gap needed between the switch contacts. This becomes a factor when you go above 25 volts DC (such as a switch to disconnect a solar panel from the solar controller). Using an AC rated switch will cause the voltage to arc across the contacts when opening the switch. I'm sorry if you have covered this in another video but, I just stumbled upon this one of your videos here for the first time. The fuses
thanks Bill for input and explaination. you are right, the black one (rated for 100 amps) is quite bad and trips at around 50 amps. I also did another video how to connect the double pole trip fuses as it is crucial. cheers, Lupo
If you have a breaker between the controller and the battery, if that breaker is off and the controller is not connected to the batteries and the panels are still producing power to the controller then the controller will be damaged?!
Hi Jay, why do you think it would be damaged? A lot of controllers don't work without the battery but the Victron also runs on the power coming from the panel.
@@JayPerrypersonal I guess it is to sense the voltage of the battery as 12 and 24V systems are supported. And it is always better to connect the battery first, but as a breaker can trip, the controller usually can cope with it and won't be damaged if the battery is cut off and PV is still online. Victron also states in the manual what type of fuse you can put between the battery and the controller and I also tried it already, nothing was damaged ;)
@@LupoDIY I always install a dule pole DC breaker switch between the panels and the solar regulator so I can just easily kill the power from the panels
@@JayPerrypersonal wise decision, I also do that, double pole breakers on both sides of the charge controller -> I also show that in my final design in ruclips.net/video/MYHCWDxNI6I/видео.html and ruclips.net/video/H5jYRlLm_VI/видео.html
Hey @truthbknwn, what exactly to you mean? As I explained in the other comment it is always good to have a fuse between the controller and the battery to protect the cables and the controller in case of a short. cheers, Lupo
If I have a bank of four 100 Ah batteries in parallel,, would I have a 100 A fuse between each battery? Suppose I have a 2000 W inverter and want to draw enough power from the battery bank for an 1800 W continuous load with an inverter efficiency of 90%. The draw from the bank would be 2000 W which at 12.5V would be 160A. Should I have a 160A fuse between each battery, or a 100A fuse because the batteries are 100Ah, or do I need fuses between the batteries at all?
Hey @slydog7131 thanks for the question. Fuses are always a good idea. Every fuse has to be able to handle the current of the battery. so if you connect 4 batteries 100A each, you need 4x fuses with at least 100A each. If you have the constant load of 100A I would recommend at least a 120A fuse as it gets super hot otherwise. does this help, cheers, Lupo
@@LupoDIY Helps, but let me review: 120A fuses BETWEEN the 100 Ah parallel batteries. How about in line to the inverter, which could reach 160A, so maybe a 200A fuse between the inverter and the battery pack? Another follow-on question: how about cable sizes? My guess: BETWEEN the parallel batteries, 1AWG to handle 110A @ 60C and then 3/0 Aught between the pack and the inverter for 165A @ 60C?
@@slydog7131 makes sense to have kind of a main switch/breaker for all batteries. if all batteries together might deliver 160A you need a 160A breaker for the main switch. yes, you are right. cheers, Lupo
ok but why do you need fuses/brakers for panels even if they are connected in parallel ? You still want to suck all the current they provide, unless you don't use appropriate wire gauge for that combined current which is a mistake anyway, I don't see how it's different from non parallel connection
Hey @beboba2498, thanks for the question. adding fuses or breakers provides an extra layer of protection for the wiring and system overall. This helps guard against unexpected issues, like animal interference or external forces causing a short. it’s just a precaution to keep things safer. cheers, Lupo
Hey @innervarium, thanks for the question. you are right, you can also use a breaker instead of fuse+switch. It just depends what you want to do and how to switch it. If you want to switch quite often, it makes more sense to have a proper switch instead of a breaker as it is easier to use. e.g. 100A breakers are "physically hard" to switch. does this help? cheers, Lupo
Hey, thanks for the question. if you are afraid of arcs you have to study the specs of a breaker/fuse how much the can handle. usually it is more than 1000Amps but lifepo4 cells might have higher currents flowing in case of a short. so double check how many amps it can handle. cheers, Lupo
Not sure how your solar charge controller runs your load too. Uhmm 😳 maybe that In itself is hazardous. Should you not be coming from the battery for your load?
hey, good point, it depends. some charge controllers (e.g. my victron smart charge controller) have separated outlets for the load to also monitor it (inc. low voltage cut off, etc). but my heavy load (like inverter) is connected to the battery. cheers, Lupo
@@LupoDIY there are several distinct divisions to Fuses, breakers and basic grounding safety. 1) DC concentrator with fuses and/or breakers. 2) AC Fuses and/or Breakers 3) Grounding wire from every unit to a pole in the ground.
Fuse rating depends on inverter peak power. I have a 1000 (1200 peak power) Watt inverter, protected with a 100 A fuse placed close to the 12V battery bank. To calculate: 1200W/12V = 100A
As Nick already wrote in his answer, it depends on the inverter. I like to use a smaller breaker for the inverter because the inverter has built in fuses which otherwise would melt first. So if I have a 2000W inverter but usually just pull 800W, I would go for a 80-100A (12V) breaker.
thanks for the question: you always need fuses. there can be a short which can lead to fire. you always have to secure all circuits even if is just 5 watts load.
You should always use a fuse to protect all the equipment, it doesn't depend on the amps as there can always be a short somewhere. Furthermore a breaker comes in handy in case you have to do some maintenance work. cheers, Lupo
Breaker between battery and Charge controller should be a double pole type, and should be rated to match the controller max input I.e. a 30A controller requires a 30A breaker
@Lupo DIY the amp rating is output, so breaker is nothing to do with that. Breaker should be amp rated to just higher than the max series rating of the panels especially if not fused. However if the maximum current is lower than the maximum series rating of the panels, then no fuse is required. For instance, a Victron smart charge controller 100/50 means maximum voltage from the panels is 100v but the 50 means maximum output from the charge controller is 50 amps. My 1200w at 74v can in theory have the controller output at 54 amps. However this is not a problem but you loose that 4 amps as the controllers maximum current output is 50 amps.
@@JayPerrypersonal You have proposed a breaker size based on max series rating of the (solar) panels, is that to protect the panels or the charge controller? My proposal was to protect a faulty charge controller from battery overload.
@@westwonic Battery overload is additionally protected by the BMS. You rate fuses mainly for protecting cables and fire risks. Device protection is something completely different and fuses are usually the wrong tool for that.
I recently installed one of these and the on off switch is working backwards. If I take it out and reinstall it the other way around will that fix this? Or is the switch working backwards caused by something else? And if the switch is backwards in its on off function does that inhibit its ability to trip the switch when there's a real surge?
Hey @noahriding5780 usually the problem is not that it doesn't trip but it can't break the arc and might catch fire when it is connected in the wrong way. hoep that help, cheers Lupo
usually you can't use 220 volt AC breakers for DC, some can be used for AC and DC but then it is written on it. so it is really important to check the specification of the breakers because it is really dangerous to use the wrong one.
Hi Bachir. It depends where you want to put the breaker? Your System is quite similar to mine so you could use more or less the same breakers. Maybe a smaller one for the battery depending on your load. cheers, Lupo
You can only use one of hose fuse/breaker shown. You need a twin pole breaker so you can disconnect both lines. That single pole breaker is also only rated for 48 v. You need to do a little more research before offering electrical advice
hey, thanks for the comment. "you can only use one breaker" for what scenario? how do you know that the single pole is rated for 48V? because it is not. officially it is rated for just 24V which is sufficient for my 12V setup btw. it always depends on the use case and the setup, there is no wrong/right in general. cheers, Lupo
@@LupoDIY 48 volts was written on the fuse in your video. With electrical, there may be many right ways to do things and also totally wrong ways. It will only be 12v (or more likely 14.2 to 14.6 volts) coming out of the solar controller. But going into the controller, it will absolutely be more than the charge voltage. as controllers step the voltage down and not up. Doing videos about electricity without the proper qualifications is not OK. There is a real fire risk with wrong advice.
Hey, you are right, on the breaker it says 42V, in the manual it says 24V but in general, I am not a big fan ob this type of breakers anyways. In general, it depends how and where you use the breakers. and as I described in the video, for the circuit of 12V, this is completely fine. For the incoming circuit from the PV, I use the double pole breaker but even this one is just around 40V max in my setup. But I am happy to hear other opinions or if you have found something that is one of your "totally wrong ways", please let us all know here on YT so we can learn from each other. cheers, Lupo
soory to many useless fuses. between the battery and charge controller for what 2 fuses in one wire? 100A fuse +30 Amp fuse at same time makes what sort of sense? yes to put into the wire between battery and charge controller is nromal but only one so put in a 30 Amp into it and all done. then 3 fuses to 3 consumers for what? from the load if you have a short than it affect the load wire by itself so to but a 5 or 10 Amp fuse into the line and all 3 or lets say 100 consumers protected against the same short , to put the same fuse befor any consumer not change anythink on it .......
Thanks Thomas for your input! You're absolutely right; I do use many fuses, and not every single one may be strictly necessary. However, I believe that each fuse plays a role in protecting specific parts of the wiring. Fuses are there primarily to protect wires. For example, if there's a thinner cable between the battery and the charge controller, relying solely on a big 100A fuse (designed to protect the connection between the battery and the inverter) isn't enough. An additional fuse is necessary to secure the circuit to the charge controller. While it may not pose a major risk in practice, since the 100A fuse would likely trip before the thin wire overheats, there's still a chance it won't happen quickly enough. So, I added another fuse to be extra cautious. On the load side, I’ve also placed individual fuses on each circuit. This way, if there’s a short circuit, only the affected device loses power rather than all of them. This setup provides a bit more control and safety, especially in preventing unnecessary downtime for other devices. Thanks again for the feedback. Cheers, Lupo
@@LupoDIY 12V systems use more Amps and need thicker cables so they dont set on fire. Even at 100A you will be limited to 1200W max. You are better off building a 48V system in a house.
@@sang3Eta thanks for the input. true, you need thicker cables. that is exactly what I also said in the video. For my small use case a 48V system would not be feasible. cheers, Lupo
Yes the PTV controller should not output the power to other device it should output to battery only and it should has a dc to AC inverter to power up ur devices. Power from controller to battery power a limited current it don’t too dangerous but power from battery to inverter would be problem it can up to 100A or more do fuse and switch should be add
Hey, thanks for your comment. My Victron charge controller has a dedicated output for the load which is quite convenient as you can switch of the load in case of an under voltage situation. You are right, there can be high current flowing from the battery, that is why I also recommend in the video a fuse as close as possible to the battery to secure the remaining part of the system. cheers, Lupo
Hello. I have two 6v deep cycle batteries each at 225AH and a 100A controller but the current wont pass through the controller to charge the battery. I tested it on one at a time not both at once as i assume the controlle wouldnt handle both 225AH combined. What am i doing wrong
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I have searched you tube extensively and there has been no video this so in depth on fuses for solar system. So this in my opinion is a diamond in the rough video. Being said 2yrs old I know there are better fuses on the market that will do better. BUT key point is , the explanations you have are solid and sound. This video brought me into the light of what I was seeking. Thank You
thanks a lot @modwrath810 for the feedback. super motivating. I will also do a similar updated video about this topic, hopefully soon ;) - cheers, Lupo
Never use non-branded fuses and breakers. The DC breaker you showed will likely not function well. They are commonly misrated, and the terminals are too small for the lugs. Great explanation on fusing the solar panel. The DC breaker from the solar panels is not there to protect the wire. It's to provide a mandatory shut off. The wire will be rated higher than 10A, so if a current from the panels is high, it won't melt the cable because it cannot get that high.
thanks @cleversolarpower, you are right. especially the cheap ones won't work very well and trip earlier. the design itself is ok and there are also good ones out there but as always, if you buy very cheap stuff you will also get bad quality. cheers, Lupo
Always use a DC breaker (like the cream colored shown) on PV system! If you have an array in series, many mpp systems run 250 to 400 volts so make sure the breaker is rated in excess. Pay attention to the polarity markings on the breaker or the breaker may be destroyed and catch fire. The black DC breakers are for battery voltages only and stay away from the no-name type shown. Use Buss or Bluesea brands.
thanks Karl for the information. Fully agree, the proper double pole breakers are preferred and if you want to avoid problem, go for a proper brand. I also show the problem of those breakers in ruclips.net/video/H5jYRlLm_VI/видео.html cheers, Lupo
great video for advice on safety for our solar systems. Thanks!
Hey @mrbard1, thanks and glad it was helpful! cheers Lupo
For large loads like pumps, relays are useful and give you more flexibility than use high amperage switches as you can neatly mount all the switches in a main panel.
thanks, that's a good suggestion, as you have a clean panel, you can use the same smaller switches and wiring gets also easier. the downside is that you need power for the relais but usually this shouldn't be a huge problem. cheers
That connection from the controller to the fuse box is kind of weird. It would make more sense to connect the fuse box to the voltage coming the battery.
thanks Peter, you are right, in general, it makes sense to connect the load to the battery directly. some charge controllers such as my victron have an output for the load. because of that they can measure the consumed energy and also provide a low voltage cut off. add this output is limited, you can't connect high load such as inverters but for lights etc it is fine. cheers, Lupo
Thanks for the video. It is very educational. I like the way you explain things, which helps absolute beginners like me. I know the video is about a year old but I am wondering if you could explain a bit more, the protections needed between the battery and the controller. I understand the concept of breaker, which also helps to disconnect the battery power source, but I think you also suggest that the controller also needs protecting, so I don't quite understand that bit. The question is, shouldn't the breaker close to the battery, also protect the controller? And why is an additional fuse needed between the controller and battery breaker, to protect the controller (around 8:20)? I hope my question makes sense.
In your example circuit, you have different segments, e.g. PV to Controller, Controller to Battery, Controller to devices/loads via FuseBox, etc. Are you able to advise what type of cable grade is needed/appropriate for each segment in order to avoid the cable melting and potentially catching fire?
Thanks.
Hey! thanks for your question. It is a bit misleading because I didn't draw the heavy load like an inverter. This inverter would be connected to the big breaker (e.g. 100A). The additional breaker in front of the controller is to secure the controller (e.g. 20A depending on the controller). That is why I have two breakers in series. A 100A breaker as close as possible to the battery wouldn't protect the controller in case of a faulty circuit because the controller can just handle 20A. Therefore it is good to add another fuse between big main battery fuse and controller. I hope that helped. Regarding the cables you just have to know what the max current is in the respective circuit and then use one of the tables (just google for "wire size amp ratings"). cheers, Lupo
@@LupoDIY Thanks very much for the comprehensive feedback. It does help.
Thanks, great tips!
Hey @ @nicko.baiculescu9363 .. glad that it was helpful
Thank you. Very good information.
thsnkd @bradsrestorations1085 you are welcome! cheers Lupo
Is it going to work and safe to use a circuit breaker just as a power shut off switch to your solar system from the solar panel lead ins?
The reason I ask this is that I found many solar charge controllers do not shut off properly when the batteries get full capacity. I had a solar charge controller melt recently from this and overcharging when it SHOULD have shut off but didn't. But then I found out other solar charge controllers also are not shutting off right. I don't see very many people talking about failures of charge controllers to shut off right also. And it doesn't work to always get the most expensive charge controller out there when you have a budget.
So I want to have an off and on switch for when I'm not around. I don't want to take any more chances of not having a shut off, but I don't want to use the plugins for the pv wire connectors themselves as the switch since it would put wear on them.
If you switch it off/on every day I would recommend a proper switch, but if it is just every other day it might be ok to use the breaker. cheers, Lupo
Thank you for the reply. @@LupoDIY
Excellent explanation of the components needed for a system.
thanks Jeffrey! glad this it was helpful, cheers, Lupo
Great video
glad that it was helpful, cheers, Lupo
Thanks for getting back to me what manufacturers do you recommend for the breakers buss, bluesea etc let me know I'm curious on what you like
Hey, Fred. In general I like to try out things, also cheap stuff from chinese, but you have to know what you buy and that you have to test it. sometimes it is crap, sometimes it is good. If you want to be on the safe side I would buy certifies breakers (e.g. UL in US or DIN in Europe). So far I haven't got really bad stuff from aliexpress, but just recently I found out that the 100A breaker trips already at around 60A ... that can happen, but the breakers usually work well but I can't recommend it for a bigger system which should be also safe and where you have to rely on those breakers. cheers, Lupo
Nice ! you are using same breaker that I am using. good video !
cool, how is your experience so far? cheers, Lupo
@@LupoDIY I am preparing to go off grid, I have built the shad, run cables from field to house, installed frames on field... bought circuit breakers and conduits,. Is a big project (60kw of storage lipo4) still in progress... the circuit breakers I choose (same as you) seemed the best choice ,but haven't tested yet.
@@marcoarpago wow, that's sounds awesome! let me know when you have tested it if everything worked as expected.
dont you think that if the battery breaker switch off, and that of the pv didnt, that will burn down the controller
hey @ksolar1062 thanks for the question. I do not see a problem there, you can also connect the controller to the PV without having a battery connected. usually controllers can handle this situation or why do you think it is a problem? cheers, Lupo
I'm a little confused because first you said that you didn't need a fuse breaker between your solar panel and the charge controller because of the low amperage of the panel, but later on you contradict that by saying that a 10A breaker would be necessary to protect voltage going to the solar panel. Can you please explain this discrepancy? Thanks.
Hey @truthbknwn, thanks for the question. This is correct, you do not need a fuse as my single solar panel can't produce more than 10amps which is fine for the cables. The problem is the power source on the other side. In case of a faulty controller it might be possible to short the PV and the battery which would lead to a high amp flow. Therefore it is always good to have a fuse between the battery and the controller/PV. I put a breaker between the PV and the controller just to have a switch in between and be on the safe side. Hope that helps? cheers, Lupo
Why do you need two sequential fuses between your battery and the controller? 80A fuse looks useless. Could you explain?
Hey Taras, thanks for the question. Sry, I didn't draw another load, the inverter, which is connected to the 80A fuse - it is mainly to protect the circuit connected to heavy load like an inverter. cheers, Lupo
Why do you connect the controller to the fuse box directly ? The power should come from the battery
good catch @Jxsanc123 - I didn't explain it in detail but my charge controller has also a connection for load which can be switched off automatically by the charge controller in case the battery soc is too low. cheers, Lupo
in addition, the MPPT "load" on that model allows the PV to power your loads directly not taking it away from battery unless voltage drops and batt takes over
I really enjoyed your video I have a question what kind of fuses and breakers do you recommend get back to me I appreciate it thank you
thanks Fred, it really depens on the use case and what you need, what load you use, etc...there is not just one right kind, unfortunately
Your solar panel has a maximum or short circuit current, which is OK to draw, so there is no reason to fuse that. Unless you place multiple panels in parallel.
hey Aliza, thanks for the feedback. you are right, it is not needed but it is very convenient to have a breaker two break the connection to the panel. and in theory there could be also current flowing from the battery into the solar system in case of a fault. cheers, Lupo
@@LupoDIY I have no breakers on the solar panels as they can only provide 8A max, only a breaker between the battery and the solar charger...
Please how can I connect the both wires in the DC breaker.
Here in Syria there is no electricity. We depend on solar energy
Hey Hani, can you describe your problem in more detail, otherwise it is difficult to help. cheers, Lupo
Do you need a fuse while using solar going into a all in one solar generator type system?
it depends on the system. usually the have fuses inside. but it is always good to protect your cables by additional fuses. They can also be used as switches which might also come in handy. cheers, Lupo
@@LupoDIY thank you!
Thanks 👍 I learnt alot 👍
Thanks Simon, that motivates to create more content ;) ... do you have any specific question which wasn't explained?
I place a circuit breaker in line with anything that is connected to the DC power bus. This offers protection and a means of disconnecting (or isolating) any circuit tied to the bus.
That white circuit breaker is a DC magnetic and thermal type, which must be wired in the correct polarity, otherwise the breaker will catch on fire during an overload.
The black circuit breaker you show is a thermal breaker made for 24 volts DC maximum. This is a low cost type, likely manufactured in China. I have had so much trouble with these Chinese breakers, I test each one with a calibrated DC current to determine the trip point, as they have a huge tolerance. For the 100 amp type, I have measured trip points from 20 to 70 amps.
The fuses you show have a maximum voltage rating of 24 volts DC.
You cannot use AC rated switches for DC due to the 10X open circuit gap needed between the switch contacts. This becomes a factor when you go above 25 volts DC (such as a switch to disconnect a solar panel from the solar controller). Using an AC rated switch will cause the voltage to arc across the contacts when opening the switch.
I'm sorry if you have covered this in another video but, I just stumbled upon this one of your videos here for the first time.
The fuses
thanks Bill for input and explaination. you are right, the black one (rated for 100 amps) is quite bad and trips at around 50 amps. I also did another video how to connect the double pole trip fuses as it is crucial. cheers, Lupo
If you have a breaker between the controller and the battery, if that breaker is off and the controller is not connected to the batteries and the panels are still producing power to the controller then the controller will be damaged?!
Hi Jay, why do you think it would be damaged? A lot of controllers don't work without the battery but the Victron also runs on the power coming from the panel.
@Lupo DIY Victron manual states it is important to connect to the batteries before connecting the panels.
@@JayPerrypersonal I guess it is to sense the voltage of the battery as 12 and 24V systems are supported. And it is always better to connect the battery first, but as a breaker can trip, the controller usually can cope with it and won't be damaged if the battery is cut off and PV is still online. Victron also states in the manual what type of fuse you can put between the battery and the controller and I also tried it already, nothing was damaged ;)
@@LupoDIY I always install a dule pole DC breaker switch between the panels and the solar regulator so I can just easily kill the power from the panels
@@JayPerrypersonal wise decision, I also do that, double pole breakers on both sides of the charge controller -> I also show that in my final design in ruclips.net/video/MYHCWDxNI6I/видео.html and ruclips.net/video/H5jYRlLm_VI/видео.html
What? You need fuse breakers for the fuse breaker between the battery and the charge controller? Now I'm really confused.
Hey @truthbknwn, what exactly to you mean? As I explained in the other comment it is always good to have a fuse between the controller and the battery to protect the cables and the controller in case of a short. cheers, Lupo
If I have a bank of four 100 Ah batteries in parallel,, would I have a 100 A fuse between each battery? Suppose I have a 2000 W inverter and want to draw enough power from the battery bank for an 1800 W continuous load with an inverter efficiency of 90%. The draw from the bank would be 2000 W which at 12.5V would be 160A. Should I have a 160A fuse between each battery, or a 100A fuse because the batteries are 100Ah, or do I need fuses between the batteries at all?
Hey @slydog7131 thanks for the question. Fuses are always a good idea. Every fuse has to be able to handle the current of the battery. so if you connect 4 batteries 100A each, you need 4x fuses with at least 100A each. If you have the constant load of 100A I would recommend at least a 120A fuse as it gets super hot otherwise. does this help, cheers, Lupo
@@LupoDIY Helps, but let me review: 120A fuses BETWEEN the 100 Ah parallel batteries. How about in line to the inverter, which could reach 160A, so maybe a 200A fuse between the inverter and the battery pack? Another follow-on question: how about cable sizes? My guess: BETWEEN the parallel batteries, 1AWG to handle 110A @ 60C and then 3/0 Aught between the pack and the inverter for 165A @ 60C?
@@slydog7131 makes sense to have kind of a main switch/breaker for all batteries. if all batteries together might deliver 160A you need a 160A breaker for the main switch. yes, you are right. cheers, Lupo
The expression is, "It's raining cats and dogs outside." A way to remember this is dogs chase cats, so cats must go first.
thanks, that's perfect 🤣 now, I will remember it
Good video
Hey, thanks, I hope it was helpful! cheers, Lupo
ok but why do you need fuses/brakers for panels even if they are connected in parallel ? You still want to suck all the current they provide, unless you don't use appropriate wire gauge for that combined current which is a mistake anyway, I don't see how it's different from non parallel connection
Hey @beboba2498, thanks for the question. adding fuses or breakers provides an extra layer of protection for the wiring and system overall. This helps guard against unexpected issues, like animal interference or external forces causing a short. it’s just a precaution to keep things safer. cheers, Lupo
Im confused, why have a fuse and a switch for a device when you could just use a breaker or switch by itself? thx
Hey @innervarium, thanks for the question. you are right, you can also use a breaker instead of fuse+switch. It just depends what you want to do and how to switch it. If you want to switch quite often, it makes more sense to have a proper switch instead of a breaker as it is easier to use. e.g. 100A breakers are "physically hard" to switch. does this help? cheers, Lupo
Is just having a dc breaker to pv enough? Would a fuse not be needed as well? I hear the dc breakers can have bad arcs
Hey, thanks for the question. if you are afraid of arcs you have to study the specs of a breaker/fuse how much the can handle. usually it is more than 1000Amps but lifepo4 cells might have higher currents flowing in case of a short. so double check how many amps it can handle. cheers, Lupo
Not sure how your solar charge controller runs your load too. Uhmm 😳 maybe that
In itself is hazardous. Should you not be coming from the battery for your load?
hey, good point, it depends. some charge controllers (e.g. my victron smart charge controller) have separated outlets for the load to also monitor it (inc. low voltage cut off, etc). but my heavy load (like inverter) is connected to the battery. cheers, Lupo
@@LupoDIY there are several distinct divisions to Fuses, breakers and basic grounding safety. 1) DC concentrator with fuses and/or breakers. 2) AC Fuses and/or Breakers 3) Grounding wire from every unit to a pole in the ground.
What size break do you need from the battery to the inverter?
Fuse rating depends on inverter peak power. I have a 1000 (1200 peak power) Watt inverter, protected with a 100 A fuse placed close to the 12V battery bank.
To calculate: 1200W/12V = 100A
As Nick already wrote in his answer, it depends on the inverter. I like to use a smaller breaker for the inverter because the inverter has built in fuses which otherwise would melt first. So if I have a 2000W inverter but usually just pull 800W, I would go for a 80-100A (12V) breaker.
@@LupoDIY How to size the circuit breaker?
How about light only,.we have 100w panel and 60a scc 80ah batery
I need FUSE or Not .
thanks for the question: you always need fuses. there can be a short which can lead to fire. you always have to secure all circuits even if is just 5 watts load.
I Have two 200 watt panels rated at 5amp each connected to a 30amp controller do I need a fuse between them ?
You should always use a fuse to protect all the equipment, it doesn't depend on the amps as there can always be a short somewhere. Furthermore a breaker comes in handy in case you have to do some maintenance work. cheers, Lupo
Breaker between battery and Charge controller should be a double pole type, and should be rated to match the controller max input I.e. a 30A controller requires a 30A breaker
thanks Nick, you are right, I also added another double pole breaker for security reasons as shown in ruclips.net/video/MYHCWDxNI6I/видео.html
@Lupo DIY the amp rating is output, so breaker is nothing to do with that. Breaker should be amp rated to just higher than the max series rating of the panels especially if not fused. However if the maximum current is lower than the maximum series rating of the panels, then no fuse is required.
For instance, a Victron smart charge controller 100/50 means maximum voltage from the panels is 100v but the 50 means maximum output from the charge controller is 50 amps. My 1200w at 74v can in theory have the controller output at 54 amps. However this is not a problem but you loose that 4 amps as the controllers maximum current output is 50 amps.
@@JayPerrypersonal You have proposed a breaker size based on max series rating of the (solar) panels, is that to protect the panels or the charge controller? My proposal was to protect a faulty charge controller from battery overload.
@@westwonic Battery overload is additionally protected by the BMS. You rate fuses mainly for protecting cables and fire risks. Device protection is something completely different and fuses are usually the wrong tool for that.
@@dominikvonlavante6113 did I mention fuses? Plus MY pair of 12 v AGM batteries don't have a BMS
I recently installed one of these and the on off switch is working backwards. If I take it out and reinstall it the other way around will that fix this? Or is the switch working backwards caused by something else?
And if the switch is backwards in its on off function does that inhibit its ability to trip the switch when there's a real surge?
Hey @noahriding5780 usually the problem is not that it doesn't trip but it can't break the arc and might catch fire when it is connected in the wrong way. hoep that help, cheers Lupo
Thank you@@LupoDIY
Is a 220 volt fuse suitable for the solar system?
usually you can't use 220 volt AC breakers for DC, some can be used for AC and DC but then it is written on it. so it is really important to check the specification of the breakers because it is really dangerous to use the wrong one.
Thx soo much for help 💖💖💖
Hi, is this dc circuit breaker enough to protect Lifepo4 batteries/PV string or should it be combined with fuses?
Hey Ivaylo, a breaker should be fine asusually, it is a fuse. cheers, Lupo
@@LupoDIY Yes it is! But I know the fuse is faster acting than the circuit breaker but I don't know if that matters for the battery or the pv module?
What breaker sizes do you suggest for one 180 watt panel connected to 20A PWM controller with 50A/12V gel battery, thank you.
Hi Bachir. It depends where you want to put the breaker? Your System is quite similar to mine so you could use more or less the same breakers. Maybe a smaller one for the battery depending on your load. cheers, Lupo
Do not recommend this kind of breaker (100A), they usually trip at a much lower current than rated and generate quite a lot of heat
Hey Pavel, fully agree, quality is not good and trips already at around 60A....I already changed it and will release a video about it soon.
A powerful battery needs a special high breaking capacity fuse, to protect against arc fault in case of a dead short! Very dangerous!
Hey Aliza, thanks, you are right. what type of fuses do you prefer? can you recommend something?
Get on with it!
You lost me at 2 breakers on the same circuit lol
true, that was a bit misleading as I didn't draw the inverter with high load which would be connected to the big 80A breaker
When you started switching pen colors….you lost me!
😂
hahahahah funny dude
thanks that you like it ;)
You can only use one of hose fuse/breaker shown. You need a twin pole breaker so you can disconnect both lines. That single pole breaker is also only rated for 48 v. You need to do a little more research before offering electrical advice
hey, thanks for the comment. "you can only use one breaker" for what scenario? how do you know that the single pole is rated for 48V? because it is not. officially it is rated for just 24V which is sufficient for my 12V setup btw. it always depends on the use case and the setup, there is no wrong/right in general. cheers, Lupo
@@LupoDIY 48 volts was written on the fuse in your video. With electrical, there may be many right ways to do things and also totally wrong ways. It will only be 12v (or more likely 14.2 to 14.6 volts) coming out of the solar controller. But going into the controller, it will absolutely be more than the charge voltage. as controllers step the voltage down and not up. Doing videos about electricity without the proper qualifications is not OK. There is a real fire risk with wrong advice.
Hey, you are right, on the breaker it says 42V, in the manual it says 24V but in general, I am not a big fan ob this type of breakers anyways. In general, it depends how and where you use the breakers. and as I described in the video, for the circuit of 12V, this is completely fine. For the incoming circuit from the PV, I use the double pole breaker but even this one is just around 40V max in my setup. But I am happy to hear other opinions or if you have found something that is one of your "totally wrong ways", please let us all know here on YT so we can learn from each other. cheers, Lupo
soory to many useless fuses.
between the battery and charge controller for what 2 fuses in one wire?
100A fuse +30 Amp fuse at same time makes what sort of sense?
yes to put into the wire between battery and charge controller is nromal but only one so put in a 30 Amp into it and all done.
then 3 fuses to 3 consumers for what?
from the load if you have a short than it affect the load wire by itself so to but a 5 or 10 Amp fuse into the line and all 3 or lets say 100 consumers protected against the same short , to put the same fuse befor any consumer not change anythink on it .......
Thanks Thomas for your input! You're absolutely right; I do use many fuses, and not every single one may be strictly necessary. However, I believe that each fuse plays a role in protecting specific parts of the wiring.
Fuses are there primarily to protect wires. For example, if there's a thinner cable between the battery and the charge controller, relying solely on a big 100A fuse (designed to protect the connection between the battery and the inverter) isn't enough. An additional fuse is necessary to secure the circuit to the charge controller. While it may not pose a major risk in practice, since the 100A fuse would likely trip before the thin wire overheats, there's still a chance it won't happen quickly enough. So, I added another fuse to be extra cautious.
On the load side, I’ve also placed individual fuses on each circuit. This way, if there’s a short circuit, only the affected device loses power rather than all of them. This setup provides a bit more control and safety, especially in preventing unnecessary downtime for other devices.
Thanks again for the feedback. Cheers, Lupo
You will burn down your house if you use 12v car fuses!
hey, why do you think so?
@@LupoDIY 12V systems use more Amps and need thicker cables so they dont set on fire. Even at 100A you will be limited to 1200W max. You are better off building a 48V system in a house.
@@sang3Eta thanks for the input. true, you need thicker cables. that is exactly what I also said in the video. For my small use case a 48V system would not be feasible. cheers, Lupo
For future reference, writing concepts with a black marker on maths paper is the most dull and boring way you can explain something.
I'll start working on my special effects and maybe throw in some interpretive dance to spice things up. Stay tuned! ;)
Wrong concept
?
Yes the PTV controller should not output the power to other device it should output to battery only and it should has a dc to AC inverter to power up ur devices. Power from controller to battery power a limited current it don’t too dangerous but power from battery to inverter would be problem it can up to 100A or more do fuse and switch should be add
Hey, thanks for your comment. My Victron charge controller has a dedicated output for the load which is quite convenient as you can switch of the load in case of an under voltage situation. You are right, there can be high current flowing from the battery, that is why I also recommend in the video a fuse as close as possible to the battery to secure the remaining part of the system. cheers, Lupo
Hello. I have two 6v deep cycle batteries each at 225AH and a 100A controller but the current wont pass through the controller to charge the battery. I tested it on one at a time not both at once as i assume the controlle wouldnt handle both 225AH combined. What am i doing wrong
sorry, just from this description it is difficult to help without having more information. cheers, Lupo
Do you have an Instagram account to ask you you some questions related to solar energy
no insta here, but you can use the youtube feature to send me an email... cheers, Lupo.