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hi, one question: if i have 4 x 12V 280Ah C100 batteries and want to do a 24V system, is it better to hook them up into: 2 in series + 2 in series and those in paralel or 2 parallel + 2 parallel and those in series ? (To get a better C Rating? Discharging rate?) as allways there are folks that say the first is better and other say the latter is better ...
@@Broxine It will not mater 2 in series and 2 in parallel or vice verse just wire it to 24v build it as to the easiest way to configure the connections obviously the shorter the wire is the less losses you will have. Have a good one.
"C" specifically refers to the discharge capacity, that is the shortest time the battery can be safely completely discharged in quantified in fractions of one hour. Time is measured on a sexagecimal system, in units of 60, so it can be evenly divided 1, 2, 3, 4, 5, or 6 ways evenly. So a 20C battery can be discharged in 3 minutes, where a 30C battery can be discharged in 2 minutes, 60C in a minute flat. That way you can multiply to get the total amperage, a 5Ah, 20C cell can discharge in 3 minutes @ 100A, where a 5Ah 30C can discharge @ 150A in 2 minutes.
This could be the best explanation/tutorial I've seen in ages. Another thing, that AA with 2Ah capacity could've been very expensive back in 2014. I barely see rechargeable AAs these days as 18650 is by far, has become the standard size for battery-powered tools.
took RUclips forever but it finally recommended me something useful, this is probably the best explaination of Ah, A, Wh and C I've ever come across. Definitely looking at batteries in a much more reasonable way now.
I like to think of the C rating as implicitly in units of per-hour (1/hour or hour^-1), so that a 2C rating means you could (in theory) discharge such a battery twice in one hour (or once in half an hour). This way, you have a calculation such as 2.2 Ah x 20/hour, and the hours obviously cancel out, leaving a measure of current.
A similar nuisance occurs with electrical power utilities and their kWh measurements - you end up sometimes thinking about kWh/hour, which always strikes me as bizarre, even though it just means kW. Great videos, BTW. :)
If you have a lipo battery and a sharp object, you can release all that stored energy much much quicker than the C rating says. Unfortunately it causes the battery to exceed its design specifications and malfunction ;-)
I was looking at power packs and powerstation, and seeing they had nearly identical or only marginally different mah ratings (which is what I thought was their capacity) even though they were immensely different sizes and hundreds of dollars different in price, I was very confused and this video has been extremely helpful
4:35 - yes that's right! coz in the context of physics, power = work done / time. so obviously work must be in the unit Joule thus Power has to do with energy.
I don't usually comment on these types of videos but this was sooo helpful thank you. We were given an assignment with this in it but it wasn't covered in any lectures.
Great explanation! A lot of people today are so confused with (Ah) and (A). These are the things the people need to know when buying power banks, vape batteries etc.
I'm so glad you're making videos again. I have a question. Why do rechargeable batteries have mAh ratings on them but non-rechargeable ones do not? Aren't regular chemical batteries also able to deliver a set amount of current in amp hours?
Great video! I always wondered if a machine would only take a number of amps it needed, or if you had too many amps if it would fail. now I know thanks to you!
That certainly cleared up a few things, I've been curious as to what the amp hours thingy on batteries actually meant. Had to watch some of this a few times before I got it.
Afrotechmods That's just me, on pretty much any video that's about something I'm not familiar with, sometimes I have to replay something several times before I understand it.
Afrotechmods you were very clear on this video. However, I too had to watch more than once since this is all new to me. At least you get more views from us newbies!! Lol.
You said that the Ah and A are diferent units, ok. at end 05:32 we got same voltage and Ah we have 11.1 x 2.2Ah = 25Wh. But you said about C rating that we save deliver A by mult. C x Ah = A but what about Watts ? 11.1v x 44A = 488Watts and 11.1v x 88A = 976 Watts. They can be calculated as Watt = Wh ?
AnthonyTV Think it's something like this: Discharge amp = mAh * C Discharge time = (Generally since Ah) 1 hour/C or C = 1hr/discharge time. 1000mAh*6 = 6 A 60min/6 = 10 min 6 A for 10 minutes The discharge amp * discharge time should always be equal for one battery.
I like this definition. It avoids the inconsistency of Ah and A. My suggestion: C= (Safely deliverable current up to full discharge) / (Nom. Deliverable Current up to full discharge in 1 hour) or also C= 1h / (time to safely full discharge).
Zephree Zen Gold well yes, however the 1C in this case cant provide more than 1 Amp without blowing up. The 6C can provide anywhere from 0 to 6 Amps before it blows up. Same capacity, just different maximum ampere outputs.
@5:30 The 20C-Lipo battery pack can "safely deliver up to 44A". How does it's capacity change if it discharges at 44A? (Is it's capacity still 2.2 Ah and so drawing 44A will exhaust the battery in 2.2/44 = .05 hrs = 3 minutes?) Also, for the same 20C battery which delivers 2.2 Ah at 11.1V (24.42 Whr), if you were to use that battery on a device that drew 200 mA at 5V (1W) then would it exhaust the battery in 24 hours (energy capacity is 24.42 Whr and load is 1W so lifetime = capcity/load = 24.42/1 ~= 24 hours)? You'd need a voltage regulator to get the 5V from 11.1V, and it too would draw some power, so would the combined lifetime be = batteryCapacityInWattHours / (1W + regulatorLoadInWatt)?
I've seen these batteries used on acrobatic quadrotors (those "warpquad" videos come to mind) which fly around for 3-8 minutes so the 3 minute estimate seems fair but I just wanted to double check!
I think the C rating was introduced to give consumers the ability to know if the battery matches the electrical load of motors. Mostly the RC market for cars, planes. As not all electric motors are equal.
I'm so glad to see your videos popping back up on my feed again. You're always clear, concise, and fun with your explanations. Keep up the stellar work!
If you're confused, you should be because this has not been explained adequately. Particularly in relation to C ratings. And not a mention of batter packs construction relating to series and parallel connection and how this relates to Amps Mah and C.
Great video!! Amp hours had me buggin'..lol. The last type battery you showed, we use those type in drone racing/freestyle and they're used in many RC hobbies. With high performance drones, the c rating is very important to us, the higher the better performance, unfortunately the cost goes up too. With an average race/freestyle drone you can hit speeds up to 70mph+ but there is also a lot of sharp turns, flips and all around changes of directions in seconds, which means the throttle stick is constantly moving. Each of the 4 motors can pull appx 15-20amps, and the speed controller chips that operate them are rated at about 40amps for buffer from bursts. So imagine the energy draw on the battery, from 0 to max and back down again, 30 times or so during a flight. What happens to us when battery starts to get low, at the end of a flight, we notice what we call voltage sag, looking at it on a flight data chart, you'll see throttle input increase, and as the quad starts to gain momentum, the battery can't handle it, and the voltage sags, just for a second or so, but in racing that's an eternity..lol. So the higher c rating of a battery, you get lower resistance and way less voltage sag near the tail end of your flight, sometimes when you need it most trying to race to the finish line.
I bought a 5 amp power supply where the voltage can go up to 30 volts. How is this Supply rated? Is it 5 amps at 30 volts or is it 5:00 amps at 1 volt? It seems the higher I turn up the voltage the lower amps it puts out. Even when the current knob is all the way up.
This taught me more that my school ever can. Im defnitely wathing your vids and subbing. Dont know if you already make videos on normal electronics and electric topics in physics for school, if not you should cause you'd make a great teacher :P
Can you do a video about how you acquired your knowledge (education, career, etc)? I'm taking electrician classes right now so I'm curious. Also, your videos are awesome.
Somebody else may've already figured this out in the 2+ years since you posted this and commented about it, but I think I figured out C-rating. Amp-hours is just another way of saying coulombs. 1 ampere of current for 1 second is 1 coulomb of charge. So 1As = 1C. Therefore, 1Ah = 3.6kC and 1mAh = 3.6C. (But it's a lot easier to say 2.2mAh and do the math off of that than to say 7.92C and have to divide that by 3.6C *first* to convert it to mAh.) The C-rating just converts coulombs or amp-seconds to amperes, but abstracts a whole lot of messy physics and chemistry calculations to save the common average person time and mental energy. The C-rating is effectively a single scalar that can be used to simplify a whole complicated mess of math including the rate of charge transfer between the two terminals of the battery (which accounts for the maximum rate of the chemical processes inside) as well as other physics effects that come into play. It takes all of that math and boils it down to a dimensionless number that divides the battery's charge (amp-seconds or coulombs) by the time unit and then multiplies the nominal charge rating to give you... how many amps the battery can deliver instantaneously. The one number is the simplified approximation of multiple derivatives for multiple effects occurring simultaneously. Confusing? Yes, for the electrical engineer. Because marketing bullpucky makes little sense to engineers. But at the same time it can save time for the engineer by providing an adequate approximation of the battery's capability to deliver current. But to the average person who may not know quite so much? One simple little C-rating number they can use to multiply the battery's nominal charge (given in amp-hours) is a cheap, quick, dirty bit of mental math that saves a whole heck of a lot of time when shopping for a battery that can deliver the needed current. EDIT My roommate also just pointed out that C-rating also works exceptionally well when talking to, say, management when proposing that you need to buy this more expensive battery over this cheaper battery. Management may or may not be able to so intuitively grasp electrical engineering. A simple number you can use to multiply a battery's charge rating to give you another number saves time. TL;DR: C-rating is marketing bullpucky, but it's marketing bullpucky that *works* and don't stink. :3 TIDE
Great video! I'm trying to power a 5V sensor with a 3.7v booster/charger pcb. What's the minimum mAh battery you think I should use? I have a 120maH lipo on it now and the board seems to dwindle and looses power 😞. Thanks for your time!
so correct me if I'm wrong. If our battery capacity is known and we like to know how many times we could charge our phone it doesn't really matter how high the voltage or Ah or our battery is. But rather what our phone could receive in terms of Amps and Voltage. right? Excellent knowledge thank you for sharing
I never liked C ratings either and you are right, they are confusing. What I do for my flashlights is just get a good brand since they don't drain batteries quickly anyhow. I use the IMR 18650s and other similar cells. The potential for danger is when you have more than one cell in a flashlight because you must balance them or they can vent or explode or maybe even burn a house down in some cases.
Paging igetcha69 (Scott)... I think this may come in handy, especially when answering questions you may be asked quite often. Thanks Afrotechmods :-) Another fine and helpful production. I plan patronage when my income seems stable. Until then you continue to have my gratitude.
Pretty easy even without the equation of voltage x capacity. Because with Voltage x Current will basically give the same answer. So 9.6 volts x 2 Amps = 19.2 Watts, or 19.2 Watts for 1 hour, or 19.2 watt-hours. For the little battery, 1.2v x 2A = 2.4 Watts, or 2.4 watts for 1 hour, or 2.4 watt-hours. Easy.
Great video indeed, but you forgot to mention one very importand thing (concidering you show us the discahrge curves you should mention that): Wh is not always Ah*V because voltage tends to drop significantly and with higher loads it drops more significantly and much faster. As you said "idealy" it IS Ah*V, but practicaly it's lower, and the difference is sometimes noticeable - with higher discharge current and higher voltage drop it reaches some 15-25% drop in Wh capacity. Like on these curves for that 1.2V battery - average voltage @ 400 mA is ~1.25V and 1.9 Ah (1.25*1.9=2.375Wh) and for 4A it will be ~1.1V and 1.7 Ah (1.1*1.7=1.87Wh) Now let's compare: 1.7/1.9 is 0.89 ratio, which is bad but not as bad as 1.87/2.375 is 0.78 ratio.
And there you have the reason that most inverters cannot run an electric motor that is close to the stated surge, because of the voltage drop required to get the motor running. now if there were some supercaps of the proper value included in the circuit of the inverter input that might make a difference.
Hi, I have a question regarding the internal resistance of 18650 battery 1- What is the risk of building a recycled 18650 lithium battery without checking and measuring the internal resistance? 2- How is the battery built after measuring and knowing the internal resistance values of the 18650 batteries, especially if the internal resistance values for each battery differ from the others for 18650 for recycled lithium batteries?
Couldn't figure out how long my power bank will keep my lens heater warm. 30 mins of googling nothing, what the fakk is this magic. Found this video after looking through a few RUclips videos. Now I can safely say that my power bank should keep my lens heater heating for about 8 and a half hours. Extremely useful video. Well explained to a practical level that's useful, compared to a lot of resources out there that state how amp-hours, watt-hours, and all that relate to each other, which makes no sense when trying to figure out how long a powerbank will last if you're me and know absolutely nothing about anything.
Tutorial request. Could you please explain the principle behind capacitor choice in circuits (when to choose ceramic vs. electrolytic, polar vs. non-polar etc.) I always get lost with the huge variety of ceramic and plastic caps. I often pick random non-polar ones based on capacitance and find that they work equally well in PWM circuits for example. The only thing I've noticed is that cheap brown ceramics react to temperature much more than blue and yellow ones. Tantalum caps are most stable. But I'm pretty sure there's more to caps than that. Of all the components I find them the most mysterious and non-intuitive. Thanks.
I'm currently testing my surprisingly large collection of AA and AAA batteries with a RS232 logging multimeter and 3.2 ohm load. This makes about 200 ma current draw. I'm logging the data to a computer and working out the total amp-hour capacity of the batteries to estimate their overall maximum charge. Seems to be working pretty good. I'm measuring mA not volts. (If i had arduino or two DMM i'd do both at the same time). Thanks for the vid.
Great video! I need help on NiMh batteries. I am into the hobby of Tamiya Mini 4wd and batteries make a great deal on our races. I normally use 2x Fujitsu AA NiMh batteries (min. 1.2v 1900mAh) on our cars. What we need to achieve is a high consistent current delivery and as well as the batteries needs to last longer. Batteries shouldn't self discharge so quickly as well. We normally charge the battery on smart chargers (we don't normally charge the batteries individually, it's a series of 4-6 cells per 100watts channel charger) for .2A - .3A. We also cycle them with a discharge rating of .5A and a voltage cut-off of .9V (multiplied how many cells we are charging per tray) and same charge rating. My question is how do we 'break-in' a new battery and how do we charge and cycle them?
good expain and understanble but I have a question : why we measure the difference potential to about 400v or 390V or so on in three lines circuit ?? as long as every line have a potential and none of them is neutral is it must be 0 instead of 400V ?
Don't forget that you shouldn't draw 88 amps from a nearly discharged battery even though your C rating is 40 and your amp hours is 2.2. In reality you should follow this guideline. C rating X remaining AH of battery. Or in other words, as you discharge your battery you should draw less current or you risk damaging the battery or shortening it's life cycle. It's not that the C rating changes as the battery depletes, it's that the AH remaining in the battery that decreases. So in a properly designed system you should monitor how much energy has gone in/out of your battery and limit your charge/discharge current based off that rather than your raw AH rating X C rating. For example: your battery is 2.2ah at C40. You have discharged it down to 1.5ah. So now 1.5 X 40 is 60 amps max current draw.
3:30 Error. The internal resistance does not consume amp hours. What it does is lowering the voltage making the battery reach cut of voltage earlier then with lower load. If you discharge the battery with 4A, there will probably still be 300mAh left in the battery that can be drained with lower current. (this feature is actually used for Volvo Hybrid cars) 4:30 Kind of wrong. Its not really correct to multiply this way 5:40 Its not really that comfusion, C have a unit of hour^-1. If the unit is included the calculation makes a lot more seance. The C rating is 20/hour....
1) The battery chemistry is limited on the amount of current it can sustain. Drawing too much current makes the voltage drop as compensation for this natural chemical resistance(bottleneck). Depleting a battery past its lowest rated voltage is possible, but will destroy your rechargeable battery, it needs to maintain a minimum voltage at all times or the battery chemistry will no longer function ideally(or safely for that matter). Anything other than that is a difference in chemistry, not a difference in the rule to not drain a battery past its spec'ed minimal voltage. 2) Not wrong at all. 3) You are sort of right on this one. The C rating is a bit ambiguous, but is a great way to get in the ballpark with your safe amperage draw.
1: My point is if you stop draining, the voltage of the battery will go up to what ever the idle voltage is for that fillrate. 2: It is. Even in idle a battery will bot get full voltage when partly drained. The result if this is that the current have to be integrated over the voltage to get the true capacity. Just multiplying just get a estimate, and it will always be over. 3: The problem i see with C rating its that its not originated from science or physics, and there for don´t have a true physical specification. But just the /hour will basically solve it. One problem here is that C rating is used in several other ways, for instance in number of cycles the battery can take... then a other unit is neaded... there should probably need a sub unit, like Cd (capacity discharge) or Ct (capacity total) or something... but people will probobly just keep using C rating in a anarchistic way
matsv201 Now that you better explain what you are pointing out, all of that is correct. 'Incorrectness' of those statements you saw seemed to exclude implied information to me, but I guess it would not be so obvious for someone new to electronics.
Thank you! Now I understand how amp-hours and watt-hours work. I have a question though. How do I measure the voltage across a 2200mAh powerbank using a DMM? Or do all powerbanks provide the same amount of voltage? I was thinking of using my powerbank as a source for my future mini-experiments.
Yes. All powerbanks provide the same voltage of 5.2V. This is the standard voltage for a USB port. Yes, the powerbanks can be used for the projects, but have an output current limit of 1Amp to 2.5Amp depending on the size of the powerbank.
i have been looking at tons of batteries on the web....6v,12, assorted amps, etc. I have even looked at step-up dc/dc coverters....12>24 and 24>48.......i am looking to power a 48v 1000watt brushless,gearless ebike motor hub.....those lithium battery packs cost more than my trike and ebike conversion kit COMBINED.....so i have been exploring the SLA battery configs...... thankyou for this video....i dont have an apple to put on your desk but is it OK if i go to the playground a little early ?
Question - how much energy (watt-hours) to charge a 200Ah 12V battery which has been discharged to 50% level? Or in other words, how much energy is lost in the process of charging a battery. Next Question - how much energy is lost when discharging the same 12V 200Ah battery and converting this from DC to AC (for home appliance use)? Do you have some formulas I can use for modeling economic feasibility of battery storage systems for solar PV projects? Thank you!
hahaha, was searching for this answer whole day without finding anything useful. Now casually watching youtube I find this vid by accident. thnx for vid :), just as I thought.
Like your videos a lot. Can you make a video about powerpack for homes like Tesla Power wall, what are things to know first, the safety, the right materials and calculations.
Interested in learning about wireless power? Subscribers can get up to 80% off my course Wireless Power to the People - Wireless Charging 101 on udemy using the coupon code "RUclips" www.udemy.com/wireless-power-to-the-people-wireless-charging-101/?couponCode=RUclips
Now I am getting my interest in this subject after becoming a doctor, hope to learn a lot in future..ty
hi, one question:
if i have 4 x 12V 280Ah C100 batteries and want to do a 24V system, is it better to hook them up into:
2 in series + 2 in series and those in paralel or
2 parallel + 2 parallel and those in series ? (To get a better C Rating? Discharging rate?)
as allways there are folks that say the first is better and other say the latter is better ...
@@Broxine It will not mater 2 in series and 2 in parallel or vice verse just wire it to 24v build it as to the easiest way to configure the connections obviously the shorter the wire is the less losses you will have.
Have a good one.
Ok
"C" specifically refers to the discharge capacity, that is the shortest time the battery can be safely completely discharged in quantified in fractions of one hour. Time is measured on a sexagecimal system, in units of 60, so it can be evenly divided 1, 2, 3, 4, 5, or 6 ways evenly. So a 20C battery can be discharged in 3 minutes, where a 30C battery can be discharged in 2 minutes, 60C in a minute flat. That way you can multiply to get the total amperage, a 5Ah, 20C cell can discharge in 3 minutes @ 100A, where a 5Ah 30C can discharge @ 150A in 2 minutes.
Thanks for the specific clarification. This should be pinned to the top of the comments.
Hence, you could say that the unit for C ratings is [1/h]
I believe c rating also has an impact on charging time that is perhaps more significant to most users to understand.
sexidecimal... my favorite math system. XD
@@error53ish I am so happy it wasn't just mewho thought of that
When a 6 minute video from 5 years ago explains batteries better than my school did this entire year
Great tutorial!
What you doing here? Xd I loved your videos! Have a nice day
Oh did you learn it from here? I am actually building a speaker with your videos rn.
When's your next cool project? :D Looking forward
wow!
R u here ?u r my favorite ♥️ youtuber
Great vid, as always. Thanks for the mention!
Yay thank you!
Afrotechmods do you know any other sources for one to llearn electronics?
Moses A
Check out the recommended channels on my channel page
EEVblog
Mo Overall Fitness Hacks
This could be the best explanation/tutorial I've seen in ages. Another thing, that AA with 2Ah capacity could've been very expensive back in 2014. I barely see rechargeable AAs these days as 18650 is by far, has become the standard size for battery-powered tools.
took RUclips forever but it finally recommended me something useful, this is probably the best explaination of Ah, A, Wh and C I've ever come across. Definitely looking at batteries in a much more reasonable way now.
I like to think of the C rating as implicitly in units of per-hour (1/hour or hour^-1), so that a 2C rating means you could (in theory) discharge such a battery twice in one hour (or once in half an hour). This way, you have a calculation such as 2.2 Ah x 20/hour, and the hours obviously cancel out, leaving a measure of current.
A similar nuisance occurs with electrical power utilities and their kWh measurements - you end up sometimes thinking about kWh/hour, which always strikes me as bizarre, even though it just means kW. Great videos, BTW. :)
its been more than a week trying to understand these three topics. well you just explained everything in 0.1 h
If you have a lipo battery and a sharp object, you can release all that stored energy much much quicker than the C rating says. Unfortunately it causes the battery to exceed its design specifications and malfunction ;-)
How does it work
step one: stab
step two: throw outside
step three: boom
I was looking at power packs and powerstation, and seeing they had nearly identical or only marginally different mah ratings (which is what I thought was their capacity) even though they were immensely different sizes and hundreds of dollars different in price, I was very confused and this video has been extremely helpful
I've been waiting for a long time to hear these terms and processes explained to me. Thanks!
this is great. nobody talks about how ampere and amp hours are different, and i was confused for long time until got it by myself.
The best video about batteries and their units i've seen so far. Congratulations!
Totally not an electrical engineer or electrician but stumbled across this and it was very clear! thanks man
Took electronics in high school now years later been playing with solar and a multimeter. Great content for a refresher!
Just learned more in 6 minutes than in 3 years of high school Electronics class. Subbed.
I used to watch you videos back then, man I learn a lot here
4:35 - yes that's right! coz in the context of physics, power = work done / time. so obviously work must be in the unit Joule thus Power has to do with energy.
I didn't even listen to it. I read your captions and everything made sense. Nice!
The way you explain this tedious topic is simply crystal clear and straight forward . Thank you I finally learned it right!
I don't usually comment on these types of videos but this was sooo helpful thank you. We were given an assignment with this in it but it wasn't covered in any lectures.
Great explanation! A lot of people today are so confused with (Ah) and (A). These are the things the people need to know when buying power banks, vape batteries etc.
Thank you very much!! A tutorial well explained like no other. Now I know what others couldn’t explain .
I'm so glad you're making videos again.
I have a question.
Why do rechargeable batteries have mAh ratings on them but non-rechargeable ones do not? Aren't regular chemical batteries also able to deliver a set amount of current in amp hours?
I'm not sure why they do this but it annoys me too. You can usually find the capacity of alkalines etc. by looking up their datasheet.
Great video! I always wondered if a machine would only take a number of amps it needed, or if you had too many amps if it would fail. now I know thanks to you!
Brilliant video as usual, my brain loved it. So did I.
Brilliant video as usual, my brain loved it. So did I.
Brilliant video as usual, my brain loved it. So did I.
TheRogerx3 Brilliant usual as video, my love brained it
So I did.
Brilliant video as usual, my brain loved it. So did I.
Brilliant video as usual, my brain loved it. So did I.
Why don't they just show your vids in physics and engineering classes instead of teaching dude. You've been SO much more helpful to me as a student!
Thanks! In some schools they do!
A Masterpiece as always....!
Ah has been a mystery for me for years untill now..
Well done tutorial on battery basics. Many are clueless.
u really rocked it bro.....it is very easy to understand by way u teach...
That certainly cleared up a few things, I've been curious as to what the amp hours thingy on batteries actually meant. Had to watch some of this a few times before I got it.
What parts were unclear? (just looking for feedback)
Afrotechmods
That's just me, on pretty much any video that's about something I'm not familiar with, sometimes I have to replay something several times before I understand it.
Afrotechmods
I thought your video was very clear, but then I am studying electrical engineering.
Afrotechmods
it's clear. Us dummies just can't absorb and retain new concepts on the first pass a lot of the time :)
Afrotechmods you were very clear on this video. However, I too had to watch more than once since this is all new to me. At least you get more views from us newbies!! Lol.
The world's best teacher
You said that the Ah and A are diferent units, ok. at end 05:32 we got same voltage and Ah we have 11.1 x 2.2Ah = 25Wh. But you said about C rating that we save deliver A by mult. C x Ah = A but what about Watts ? 11.1v x 44A = 488Watts and 11.1v x 88A = 976 Watts. They can be calculated as Watt = Wh ?
thanks about the explanation, Finally I know about C rate and relation to Amper Hours. The video have helped me understand my problem
wow, what a great video to gain an intuitive understanding for all these numbers!
Wow! This video is very well done and clarified a lot. Thank you!!
If power consumption is measured in watts you can convert watts to amps by simply dividing the watts by the voltage you are using.
C rating = How much time faster than 1h can you discharge the battery.
So 1C for 1000mah can give 1amp for 1h
6C for 1000mah can give 6amp for 10min
AnthonyTV
Think it's something like this:
Discharge amp = mAh * C
Discharge time = (Generally since Ah) 1 hour/C or C = 1hr/discharge time.
1000mAh*6 = 6 A
60min/6 = 10 min
6 A for 10 minutes
The discharge amp * discharge time should always be equal for one battery.
So you mean It is equal?
I like this definition. It avoids the inconsistency of Ah and A. My suggestion:
C= (Safely deliverable current up to full discharge) / (Nom. Deliverable Current up to full discharge in 1 hour)
or also
C= 1h / (time to safely full discharge).
Zephree Zen Gold well yes, however the 1C in this case cant provide more than 1 Amp without blowing up.
The 6C can provide anywhere from 0 to 6 Amps before it blows up. Same capacity, just different maximum ampere outputs.
@@anthonyvictor883 Find A, T
A=BC
T=60/C
A= amps
B= battery ah rating
C= battery C rating
T= time in minutes
This guy teaches me more than my whole 16 years in school
Short, clear and informative. That was very good.
@5:30 The 20C-Lipo battery pack can "safely deliver up to 44A". How does it's capacity change if it discharges at 44A? (Is it's capacity still 2.2 Ah and so drawing 44A will exhaust the battery in 2.2/44 = .05 hrs = 3 minutes?)
Also, for the same 20C battery which delivers 2.2 Ah at 11.1V (24.42 Whr), if you were to use that battery on a device that drew 200 mA at 5V (1W) then would it exhaust the battery in 24 hours (energy capacity is 24.42 Whr and load is 1W so lifetime = capcity/load = 24.42/1 ~= 24 hours)? You'd need a voltage regulator to get the 5V from 11.1V, and it too would draw some power, so would the combined lifetime be = batteryCapacityInWattHours / (1W + regulatorLoadInWatt)?
I've seen these batteries used on acrobatic quadrotors (those "warpquad" videos come to mind) which fly around for 3-8 minutes so the 3 minute estimate seems fair but I just wanted to double check!
I think the C rating was introduced to give consumers the ability to know if the battery matches the electrical load of motors. Mostly the RC market for cars, planes. As not all electric motors are equal.
Highly appreciated, far better than my professors.
Excellent tutorial. Same as battery advertised in Wh / V = Ah
I will have to watch it a couple more times. My head is spinning. Good instruction. If I were smarter I could say you made it easier to understand
Excellent video. Difficult topic explained in clear and in understandable terms.
I'm so glad to see your videos popping back up on my feed again. You're always clear, concise, and fun with your explanations. Keep up the stellar work!
If you're confused, you should be because this has not been explained adequately. Particularly in relation to C ratings. And not a mention of batter packs construction relating to series and parallel connection and how this relates to Amps Mah and C.
Great video!! Amp hours had me buggin'..lol. The last type battery you showed, we use those type in drone racing/freestyle and they're used in many RC hobbies. With high performance drones, the c rating is very important to us, the higher the better performance, unfortunately the cost goes up too. With an average race/freestyle drone you can hit speeds up to 70mph+ but there is also a lot of sharp turns, flips and all around changes of directions in seconds, which means the throttle stick is constantly moving.
Each of the 4 motors can pull appx 15-20amps, and the speed controller chips that operate them are rated at about 40amps for buffer from bursts. So imagine the energy draw on the battery, from 0 to max and back down again, 30 times or so during a flight. What happens to us when battery starts to get low, at the end of a flight, we notice what we call voltage sag, looking at it on a flight data chart, you'll see throttle input increase, and as the quad starts to gain momentum, the battery can't handle it, and the voltage sags, just for a second or so, but in racing that's an eternity..lol. So the higher c rating of a battery, you get lower resistance and way less voltage sag near the tail end of your flight, sometimes when you need it most trying to race to the finish line.
Great video! Thanks for clarifying that the units do not actually work out when dealing with C ratings.
I bought a 5 amp power supply where the voltage can go up to 30 volts. How is this Supply rated? Is it 5 amps at 30 volts or is it 5:00 amps at 1 volt? It seems the higher I turn up the voltage the lower amps it puts out. Even when the current knob is all the way up.
This taught me more that my school ever can. Im defnitely wathing your vids and subbing. Dont know if you already make videos on normal electronics and electric topics in physics for school, if not you should cause you'd make a great teacher :P
Cool!! But I heard that if you connect an ammeter directly to the battery terminals, it would be very destructive, especially without a load.
Can you do a video about how you acquired your knowledge (education, career, etc)? I'm taking electrician classes right now so I'm curious. Also, your videos are awesome.
you explain better than most professors out there
I Learned so much from you, thanks for that! Things i Never thought i could grasp, now become clear to my aging Brain. Greetings from Germany !
Who r this assholes who put dislikes
Somebody else may've already figured this out in the 2+ years since you posted this and commented about it, but I think I figured out C-rating.
Amp-hours is just another way of saying coulombs. 1 ampere of current for 1 second is 1 coulomb of charge. So 1As = 1C. Therefore, 1Ah = 3.6kC and 1mAh = 3.6C. (But it's a lot easier to say 2.2mAh and do the math off of that than to say 7.92C and have to divide that by 3.6C *first* to convert it to mAh.)
The C-rating just converts coulombs or amp-seconds to amperes, but abstracts a whole lot of messy physics and chemistry calculations to save the common average person time and mental energy.
The C-rating is effectively a single scalar that can be used to simplify a whole complicated mess of math including the rate of charge transfer between the two terminals of the battery (which accounts for the maximum rate of the chemical processes inside) as well as other physics effects that come into play.
It takes all of that math and boils it down to a dimensionless number that divides the battery's charge (amp-seconds or coulombs) by the time unit and then multiplies the nominal charge rating to give you... how many amps the battery can deliver instantaneously.
The one number is the simplified approximation of multiple derivatives for multiple effects occurring simultaneously.
Confusing? Yes, for the electrical engineer. Because marketing bullpucky makes little sense to engineers. But at the same time it can save time for the engineer by providing an adequate approximation of the battery's capability to deliver current.
But to the average person who may not know quite so much? One simple little C-rating number they can use to multiply the battery's nominal charge (given in amp-hours) is a cheap, quick, dirty bit of mental math that saves a whole heck of a lot of time when shopping for a battery that can deliver the needed current.
EDIT
My roommate also just pointed out that C-rating also works exceptionally well when talking to, say, management when proposing that you need to buy this more expensive battery over this cheaper battery. Management may or may not be able to so intuitively grasp electrical engineering. A simple number you can use to multiply a battery's charge rating to give you another number saves time.
TL;DR: C-rating is marketing bullpucky, but it's marketing bullpucky that *works* and don't stink. :3
TIDE
Very well produced video and accurate information. Bravo!
Great video! I'm trying to power a 5V sensor with a 3.7v booster/charger pcb. What's the minimum mAh battery you think I should use? I have a 120maH lipo on it now and the board seems to dwindle and looses power 😞. Thanks for your time!
so correct me if I'm wrong. If our battery capacity is known and we like to know how many times we could charge our phone it doesn't really matter how high the voltage or Ah or our battery is. But rather what our phone could receive in terms of Amps and Voltage. right?
Excellent knowledge thank you for sharing
GREAT!.. NOW I UNDERSTAND CLEARLY ABOUT BATTERY CAPACITY IN HRS, WHRS AND C RATINGS
THANKS BRO
Good voice, clearly speech and very good videos.
I never liked C ratings either and you are right, they are confusing. What I do for my flashlights is just get a good brand since they don't drain batteries quickly anyhow. I use the IMR 18650s and other similar cells. The potential for danger is when you have more than one cell in a flashlight because you must balance them or they can vent or explode or maybe even burn a house down in some cases.
You've cleared my confusions...thanks.
Paging igetcha69 (Scott)...
I think this may come in handy, especially when answering questions you may be asked quite often.
Thanks Afrotechmods :-)
Another fine and helpful production. I plan patronage when my income seems stable. Until then you continue to have my gratitude.
nice one mate, will take a look :)
thank you , I've got a circuits midterm in 6 hours and this helped!
Now I know what those C ratings are for and why people were multiplying them with the mAh. Thank you!
Thank you so much for explaining it so nicely. You’ve answered quite a few things I’ve had on my mind.
Pretty easy even without the equation of voltage x capacity. Because with Voltage x Current will basically give the same answer. So 9.6 volts x 2 Amps = 19.2 Watts, or 19.2 Watts for 1 hour, or 19.2 watt-hours.
For the little battery, 1.2v x 2A = 2.4 Watts, or 2.4 watts for 1 hour, or 2.4 watt-hours. Easy.
awesome video. Good job!
I enjoyed every detail explained at an engineer level.
Great video indeed, but you forgot to mention one very importand thing (concidering you show us the discahrge curves you should mention that): Wh is not always Ah*V because voltage tends to drop significantly and with higher loads it drops more significantly and much faster. As you said "idealy" it IS Ah*V, but practicaly it's lower, and the difference is sometimes noticeable - with higher discharge current and higher voltage drop it reaches some 15-25% drop in Wh capacity. Like on these curves for that 1.2V battery - average voltage @ 400 mA is ~1.25V and 1.9 Ah (1.25*1.9=2.375Wh) and for 4A it will be ~1.1V and 1.7 Ah (1.1*1.7=1.87Wh)
Now let's compare: 1.7/1.9 is 0.89 ratio, which is bad but not as bad as 1.87/2.375 is 0.78 ratio.
And there you have the reason that most inverters cannot run an electric motor that is close to the stated surge, because of the voltage drop required to get the motor running. now if there were some supercaps of the proper value included in the circuit of the inverter input that might make a difference.
wtf 9 amps from a double a battery. you're my fave man.
Hi,
I have a question regarding the internal resistance of 18650 battery
1- What is the risk of building a recycled 18650 lithium battery without checking and measuring the internal resistance?
2- How is the battery built after measuring and knowing the internal resistance values of the 18650 batteries, especially if the internal resistance values for each battery differ from the others for 18650 for recycled lithium batteries?
Great explanation to calculate battery life and understand C ratings!
Amazing video, exactly what I was looking for.
Couldn't figure out how long my power bank will keep my lens heater warm.
30 mins of googling nothing, what the fakk is this magic.
Found this video after looking through a few RUclips videos. Now I can safely say that my power bank should keep my lens heater heating for about 8 and a half hours.
Extremely useful video. Well explained to a practical level that's useful, compared to a lot of resources out there that state how amp-hours, watt-hours, and all that relate to each other, which makes no sense when trying to figure out how long a powerbank will last if you're me and know absolutely nothing about anything.
Meow
Thanks for making this very clear for dummies like me to learn!
We need more videos on batteries like this!
- Now, are you confuse?
Me: [nodding to the screen]
- Because you should be
Me: *smirk*
Tutorial request. Could you please explain the principle behind capacitor choice in circuits (when to choose ceramic vs. electrolytic, polar vs. non-polar etc.) I always get lost with the huge variety of ceramic and plastic caps. I often pick random non-polar ones based on capacitance and find that they work equally well in PWM circuits for example. The only thing I've noticed is that cheap brown ceramics react to temperature much more than blue and yellow ones. Tantalum caps are most stable. But I'm pretty sure there's more to caps than that. Of all the components I find them the most mysterious and non-intuitive. Thanks.
Thanks for the video. Immediately clarify the areas I could not understand.
I'm currently testing my surprisingly large collection of AA and AAA batteries with a RS232 logging multimeter and 3.2 ohm load. This makes about 200 ma current draw. I'm logging the data to a computer and working out the total amp-hour capacity of the batteries to estimate their overall maximum charge. Seems to be working pretty good. I'm measuring mA not volts. (If i had arduino or two DMM i'd do both at the same time). Thanks for the vid.
Great video! I need help on NiMh batteries. I am into the hobby of Tamiya Mini 4wd and batteries make a great deal on our races. I normally use 2x Fujitsu AA NiMh batteries (min. 1.2v 1900mAh) on our cars. What we need to achieve is a high consistent current delivery and as well as the batteries needs to last longer. Batteries shouldn't self discharge so quickly as well. We normally charge the battery on smart chargers (we don't normally charge the batteries individually, it's a series of 4-6 cells per 100watts channel charger) for .2A - .3A. We also cycle them with a discharge rating of .5A and a voltage cut-off of .9V (multiplied how many cells we are charging per tray) and same charge rating. My question is how do we 'break-in' a new battery and how do we charge and cycle them?
good expain and understanble
but I have a question :
why we measure the difference potential to about 400v or 390V or so on in three lines circuit ??
as long as every line have a potential and none of them is neutral
is it must be 0 instead of 400V ?
Don't forget that you shouldn't draw 88 amps from a nearly discharged battery even though your C rating is 40 and your amp hours is 2.2.
In reality you should follow this guideline. C rating X remaining AH of battery. Or in other words, as you discharge your battery you should draw less current or you risk damaging the battery or shortening it's life cycle. It's not that the C rating changes as the battery depletes, it's that the AH remaining in the battery that decreases. So in a properly designed system you should monitor how much energy has gone in/out of your battery and limit your charge/discharge current based off that rather than your raw AH rating X C rating.
For example: your battery is 2.2ah at C40. You have discharged it down to 1.5ah. So now 1.5 X 40 is 60 amps max current draw.
3:30 Error.
The internal resistance does not consume amp hours. What it does is lowering the voltage making the battery reach cut of voltage earlier then with lower load. If you discharge the battery with 4A, there will probably still be 300mAh left in the battery that can be drained with lower current. (this feature is actually used for Volvo Hybrid cars)
4:30 Kind of wrong.
Its not really correct to multiply this way
5:40 Its not really that comfusion, C have a unit of hour^-1. If the unit is included the calculation makes a lot more seance.
The C rating is 20/hour....
1) The battery chemistry is limited on the amount of current it can sustain. Drawing too much current makes the voltage drop as compensation for this natural chemical resistance(bottleneck). Depleting a battery past its lowest rated voltage is possible, but will destroy your rechargeable battery, it needs to maintain a minimum voltage at all times or the battery chemistry will no longer function ideally(or safely for that matter). Anything other than that is a difference in chemistry, not a difference in the rule to not drain a battery past its spec'ed minimal voltage.
2) Not wrong at all.
3) You are sort of right on this one. The C rating is a bit ambiguous, but is a great way to get in the ballpark with your safe amperage draw.
1: My point is if you stop draining, the voltage of the battery will go up to what ever the idle voltage is for that fillrate.
2: It is. Even in idle a battery will bot get full voltage when partly drained. The result if this is that the current have to be integrated over the voltage to get the true capacity. Just multiplying just get a estimate, and it will always be over.
3: The problem i see with C rating its that its not originated from science or physics, and there for don´t have a true physical specification. But just the /hour will basically solve it.
One problem here is that C rating is used in several other ways, for instance in number of cycles the battery can take... then a other unit is neaded... there should probably need a sub unit, like Cd (capacity discharge) or Ct (capacity total) or something... but people will probobly just keep using C rating in a anarchistic way
matsv201 Now that you better explain what you are pointing out, all of that is correct. 'Incorrectness' of those statements you saw seemed to exclude implied information to me, but I guess it would not be so obvious for someone new to electronics.
well taught. appreciate the illustrations. will make me into a smarter and more capable shopper for sure.
Thank you! Now I understand how amp-hours and watt-hours work.
I have a question though. How do I measure the voltage across a 2200mAh powerbank using a DMM? Or do all powerbanks provide the same amount of voltage? I was thinking of using my powerbank as a source for my future mini-experiments.
Yes. All powerbanks provide the same voltage of 5.2V. This is the standard voltage for a USB port. Yes, the powerbanks can be used for the projects, but have an output current limit of 1Amp to 2.5Amp depending on the size of the powerbank.
i have been looking at tons of batteries on the web....6v,12, assorted amps, etc. I have even looked at step-up dc/dc coverters....12>24 and 24>48.......i am looking to power a 48v 1000watt brushless,gearless ebike motor hub.....those lithium battery packs cost more than my trike and ebike conversion kit COMBINED.....so i have been exploring the SLA battery configs...... thankyou for this video....i dont have an apple to put on your desk but is it OK if i go to the playground a little early ?
Your videos are awesome. Could you please make a video explaining what it means for a electrical component to draw too much current?
great explanation now I understand how this works and what's the difference in between
Great video. I'd like to have seen a little more mention of the hazard of over discharging some batteries. Venting a Li-Po is bad lol.
Dear Sir,
Nice expiation. Please be good enough to explain when you discharge 2000mAx1Hr what will be the terminal voltage.
brs...VCM.
Magnificent and easy to understand.
Thank you.
Question - how much energy (watt-hours) to charge a 200Ah 12V battery which has been discharged to 50% level? Or in other words, how much energy is lost in the process of charging a battery.
Next Question - how much energy is lost when discharging the same 12V 200Ah battery and converting this from DC to AC (for home appliance use)? Do you have some formulas I can use for modeling economic feasibility of battery storage systems for solar PV projects?
Thank you!
I was literally just researching this. Thank you so much!
hahaha, was searching for this answer whole day without finding anything useful. Now casually watching youtube I find this vid by accident. thnx for vid :), just as I thought.
Very nice and effective video presentation.😊😊😊😊😊❤❤🎉🎉Thank you.
Like your videos a lot. Can you make a video about powerpack for homes like Tesla Power wall, what are things to know first, the safety, the right materials and calculations.