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Ep 155 LifePo4 Lithium Marine Battery Install | One Year Debrief
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- Опубликовано: 27 мар 2024
- EXPENSIVE MISCALCULATION
As longtime viewers will know, the point of this channel has never been to shine a favorable light on ourselves. Instead, we're brutally honest when it comes to admitting our fails. And despite all efforts to be the “no drama” channel, things rarely go perfectly for very long.
So with that in mind, I miscalculated one major aspect of our new battery install last year, and that was in choosing the amperage limit for our Daly BMS units. For sailors (or even RV users), I would say that the issue comes down to how you determine both your battery capacity (in Amp Hours) and how you calculate your BMS size (max Amp draw).
In many if not most cases, these choices will be bounded, literally, by space constraints. My wizened take on the process is to start by making sure your battery capacity is adequate to the need, and once this is determined, simply choose a BMS size that maximizes use of that available capacity. The above might sound obvious, and perhaps it was, but I did it wrong, basing BMS size on expected max draw instead of capacity. It is important to note that Discharge Capacity, or the ability to deliver what most people would imagine as Cold Cranking Amps, is lower for LifePo4 type battery chemistries. For example, a 100Ah hour battery with a 1C discharge limit of 100A will be woefully short if your bow thruster draws north of 600A, as ours turns out to consume. And for sailors, you must add windlass amps to the bow thruster number. This is because you might be needing both pieces of equipment at the same time for Med mooring with anchor. Figure 1500W nominal at 24V=62.5A for our Lofrans Leopard windlass.
When calculating draw vs amp hours, note that amps and amp hours are not the same. Therefore, to provide a simple conversion the battery engineers will tell you that max draw should be 1C or some such, with 1C being 1x capacity for whatever cells you have. Other brands or models of cell could spec different numbers, and even EVE (brand) states that you can draw up to 2C if done rarely. These max discharge limits will be controlled by the BMS, which is programmed internally to intervene as discharge limits are reached. And of course, with each increase in amp draw that is chosen, the BMS units will be physically larger and more expensive.
For me, the error was rooted (as stated in the video) with an incorrect spec shown in our purchasing documents concerning the bow thruster, which is a Vetus monster of a thruster. These thrusters have been manufactured for decades and are still substantially the same today as they were when the boat was manufactured. Yet there are a maddening number of variables involved, including tunnel size, prop size and number of blades, voltage, amp draw, etc. And due to our thruster motor location, squeezed between black and greywater tanks, visual inspection of the manufacturer’s production plate is impossible. No problem. Oyster knew which model they installed, so we went with that.
Except, not. I discovered this when we first started using the bow thruster. With more than a second or two of activation, the entire house bank electrical system would crash. Alarms would sound, the chartplotter and bow thruster controls would reset, rendering them useless. Luckily, engine operation was unaffected. Recovery was quick for the bow thruster, but over a minute for the plotter.
These crashes were the result of the BMS units, all three of them, shutting down at once when they hit their max amp limit. This did the job they were intended for, protecting the batteries, but a shutdown of this sort under intense load is not good for other devices sharing the system due to the large voltage spikes that accompany the event.
Voltage spikes can be devastating, although I suspect them to be more dangerous to 12V systems as the amperage there is doubled in comparison to a 24V system. In any event, it turned out that our older voltage “droppers”, the devices that convert voltage from 24V to 12V, were the most vulnerable. Newer Victron models seemed unaffected. We may have also lost an older GPS antenna, and of course the 24V alternator rectifier and diode pack shown in the episode. And know that fuses and breakers protect against amps, not voltage increases (within reason).
All told, we’re looking at about $1,100 for the upgraded BMS units, upgraded wiring, lugs, etc at $270+/-, $75 for alternator rectifier and diode packs, Raymarine RS150 GPS at $250, 2x Victron Orion 24/12-15 droppers at $45 each, and five full days of labor to complete the install.
We sincerely hope that these lessons might be useful to others.
sailing yacht talisman, sailing, sailing youtube, boating, top sailing, oyster yachts, oyster sailboats, oyster 485, offshore, bluewater, blue water, sailing vlog, sailing vblog, sailing channels, sailing videos, cruising, monohull, EVE batteries, LifePo4, LFP, installing marine lithium batteries, Daly BMS, alternator failure, voltage spike
Nice work, that temperature must be tough to work in! Appreciate all of the information you put in your project videos. Happy sailing
Oh, it's brutal. October and November are still very hot, still trailing the summer. Once you get into December it's beautiful. But you have to get the work done early to enjoy it. And thanks for being with us.
Glad to see you back online kevin. 😊
You bet. Finally getting back into the groove.
You can't be careful enough on these electrical systems. No guessing your way through it. Good job Kevin!
Hi Greg. LifePo4 installs are particularly tricky. It's why there's so much wrong information out there.
Great to see you back Kevin, quality video as always. We just moved onto Osprey this week in the UK. Still working through all the lockers of spare parts and stuff that we haven’t been sailing yet. Plus it hasn’t stopped blowing 30+ every day. Looking forward to getting going soon.
Great to hear. I assume by the pic that Osprey is an Oyster. What kind of details can you give? And where exactly are you? It's only April, so the sailing season should improve in the upcoming weeks I would think.
@@SailingTalisman Oyster 56, currently in the UK having flown over from Aus. We chatted a few months ago when we were flying around looking at all the options. You were so helpful.
Sorry, I forgot which ch I’m on, it’s Sally here from Sydney, just getting all my connections up and running. It’s been a very hectic few weeks
Holy cow, what a lesson to pass on! Weight loss by battery pack repairs, not the advised method to lose a couple. Amazingly well done sir!
So true. I lost about 10lbs during this crazy 7 days. And thanks as always Dan for being with us.
Great looking setup. I also build my own battery banks using EVE Lithium Cells. If boaters who want/need a high reserve bank only realized that a DIY setup like this gives you DOUBLE at least, the AmpHour Capacity over buying a Battleborn or Dakota or Victron bank. The external DALY bms is 25x greater than internal cheap budget BMS's that these guys are using. On my Daly300amps I changed the wire at the connector to 0 Gauge to accommodate that surge that gets 4 gauge "warm" on occasions.
Some tool suggestions, I like a pumping hydraulic crimper and a Klein small gauge hand crimper over those cheap thin ones. Klein color codes there's as well. One addition I've seen used on vessels with Bow & Stern Thrusters are EATON SoftStarts to eliminate huge surges some older motors will draw. Although that might be in the SuperYacht category of needs.
I just wish others would look at your setup before they shell out big bucks for brand name inferior batteries. With your system if you lose a cell or two , EASILY replaced at about $100ish per cell.
I also made my own bus bars out of 3/8" Copper bar and the Cells love all that meat between them.
I want to give credit where it's due as well. Everything I have learned about Batteries and Inverters and Wiring anything Off Grid related has come via Will Prowse of DIY Solar and his YT channel can be a huge wealth of RUclips University Content. I'd say I have a Masters at this point and his Doctorate level knowledge is always a joy to watch and learn from.
Cheers and Keep yer Keel Down folks !!
SV Jaz
SV Hydra
Well thanks for the kind words. It nice knowing others are doing what we've done. Per your comment, first I would say that we were somewhat backed into building a raw cell battery bank due the the fact that none of the drop-in battery vendors were making a case that fit our battery box. We could get the max of about 560Ah with Battleborn or similar, with a lot of extra space in the box. And I suspect that even our previous Gel batteries were not delivering the full punch our bow thruster was wanting.
So for the casual viewer, the main difference between what we have and a drop-in case battery is that if you pulled the cover off the drop-in case, you would see the same cells, along with a BMS squeezed in along the side. By necessity, this BMS must be very thin in order to fit, and it won't ever get any air circulation. Note too that several of the main BMS suppliers are not really offering large-amp versions, and this is probably due to internal switching limitations. So if you're putting a 200A BMS on a 280Ah pack, you'll be limited to 200A draw (leaving 80A on the table) at 1C discharge of 280Ah. This was the miscalculation I spoke of in the episode, although for me it was worse since I was so focused on amp draw (and being wrong at that) that I missed the total capacity of each of my 3 packs by 130A (by installing 150A BMS units on 280Ah cells).
The benefit of the drop-in versions (as opposed to raw cells) is that all the wiring is run and tested by others prior to shipping. But this can sometimes lead people to think they can just make the switch without considering the other parts of their electrical system.
As for DIY Solar, I would say that I too am a huge fan of Will Prowse. The thing I like is that he doesn't take the vendor's word on specs. And they never seem to learn, sending him substandard, bargain basement crap, which he then tears apart and exposes. He's also super enthusiastic when he finds something he likes. So he's not just out there to diss products.
Finally, I copied Will's trick of using flattened 1/2" copper plumbing tubing for a bus bar. This followed from EVE batteries included bus bars only working as long as the cells were stacked long-side to long-side. When you turned the corner to short-side to short-side the included bars were too short and didn't fit. The copper is a nice workaround because there is very little opportunity for resistance to vary.
Thanks as always for piling us all on top of your grind. Your efforts make the world just a bit better for everyone.
Wow! Thanks Robert. Those are kind words, I think. I have a theory that people don't respect what they don't work for. And this kind of work does indeed provide a certain pride of ownership when it finally gets to working right. So thanks for being with us.
You would have been better served by adding soft start to the bow thruster! Get clip on covers 3d printed for your connector links much safer! Hydraulic crimpers usually have a wider crimp area & exert more pressure. 😊
Hi Jack. You know, I've been looking for the covers and couldn't find anything like that. Not sure they would work now though since I have about 1/2" clear above the BMS fans and need that room for the air to go in. As for the soft-start, I think you do need a bit of punch from the bow thruster or it won't have the desired effect. It's working fine now though, so I think I'll let it be. Thanks for being with us.
@@SailingTalisman take photos with a ruler and a 3d print place can make them up or ask on a 3d printing forum for someone to take on the job and post them to you!
Great job ! Nice setup, for the marine application Daly bms is good pick .
Thanks Marc!
Another good 'un! Thanks for sharing the great info. Nice to see you floating again!
Thanks Rick. It's great having you!
Kevin, great video, I was considering changing to lithium batteries but it looks very complicated and I didn’t want them under our bunk.
Great comment about the rain, you would struggle in England 🏴
Take care Mike
Ha! Thanks Mike. We bought Talisman in Scotland (where I did the first major refit) and we loved it so much we're heading back in May for a month. As for the batteries, get drop-in versions like the ones from Battleborne. All the wiring and testing are done by others. And LifePo4 battery chemistry isn't prone to thermal runaway and fire.
Several companies offer Lifepo4 packs in SS/steel water sealed casings to be used boats/adventure vehicles & still be repairable ! There are also Rack mount packs. These types have 3 connectors + - & data making your wiring easy.
You should connect a large lead battery between your high output alternator, as a charging buffer between the alternator and the LiFePO4 batteries. Lead can take a lot of abuse. Also, consider a large Starting capacitor bank (basically what a soft start does) at your connections to your bow thruster, to take that huge start up power drawl spike, which is what is over juicing your BMS's. That will reduce the power drawl required. You can look up videos how to build one, that some youtubers uses to start their car with. It's not very expensive to do. Also, you should just have a stout 3-way switch between your high output alternator and your house LiFePO4 batts and to your bow thruster and take the house bank completely out of the loop, do allow direct supply current between your alternator directly to your bow thruster, which the engine is on. And in that direct link between the two, have whatever step up regulator you need to supply ample current to the bow thruster.
Where? That's the big problem with adding a lead-acid battery in the system. There is just so little unused space on a true cruising sailboat. So in lieu of that, we're using Sterling Power Products APD, or alternator protection device, which is designed to do the same thing (intercept voltage spikes and ground them should they occur). To the eye it's a box about 3" cubed that bridges the pos and neg posts of the alternator. About the simplest wiring you could imagine. As for the rest, I'm reluctant to fix what isn't broke, and the bow thruster circuit was designed by Oyster with help from Vetus (bow thruster mfr). As is typical for us RUclipsrs, our episodes arrive months after being videoed, so I suppose I should have mentioned that the system has been up and running perfectly since the upgrade to larger BMS units. All that was needed was unimpeded short-term access to 650A or so of 24V current. As for taking the house bank completely out of the loop, that would never work because the alternator has nowhere near the ability to provide that type of amp output. The original Valeo 24V alternator produced a claimed output of 80A, but rarely produced more than 50A, while our new H.O. 110A version puts out about 75-80A. This is one issue that installers have to face, that while LifePo4 batteries like ours can accept an insane charge current (1C=280A), where would you find that? In answer, you need to be able to limit charge current output to what alternators and battery chargers can safely supply. In our case, a Sterling Power Products ProReg-DW external voltage regulator for the alternator, and internal programming limiting our Mastervolt Chargemaster 24/110-2 charger to the max 110A of claimed output, which it actually provides quite impressively. Thanks for the great comment and don't take what I say in a negative way. When working within an electrical plan that is 30 years old, we have to fit what we do into the limitations provided. Even adding a new alternator or some such seems to always bump up against physical limitations.
Hi folks, just an excuse to leave a comment and feed the YT algorithm for ya. I think the order of connecting pos/neg vs. sparks is irrelevant, a circuit is a circuit. The key is to not have a load in the circuit when hooking things up, then no current flow and no sparks. Remember that electrons are negatively charged, so in a negative ground system you are charging the structure of the vehicle with the potential for electrons to flow back to the positive side. DC flows from negative to positive, although that's also irrelevant. I believe what you are thinking of is rules for jump starting a dead battery... since off-gassing from the battery could be explosive, it's best to hook your jumpers to the positive terminal of the battery and _then_ hook the negative cable of the jumpers to a grounded frame member _away_ from the battery so when it does spark it's not near where it can blow up in your literal face. Just my .02, again, feed the hungry algorithm lol.
I think the reason that you're 'supposed' to connect the negative car jumper cable _last_ (and remove it _first_ ) is because the negative terminal is connected to the chassis ground... therefore if you connected it _first_ and then accidentally fumbled/dropped the positive cable into the engine bay, onto anything that is grounded (i.e. the engine, or basically any bare metal), then you will end up with a 💥 DIRECT SHORT 💥 across the terminals of the battery in the _other_ car (the one helping to jump start the dead car).
I have no idea how sailboats are grounded, but it looks like Kevin has the batteries in a wooden box? Still, I assume that all metal appliance chassis are connected to ground (therefore it's slightly more safe to connect the negative wire LAST, because of the slight chance of fumbling the positive cable into some nearby metal that happens to be grounded).
@@hxhdfjifzirstc894 Agreed. Won't fix sparks, but if there's less of an oops opportunity then so much the better - Cheers!
Looks pretty brutal working in those temperatures Kevin.That was a big job on the electrical system and it isn’t done until it is done.😉👍⛵️
Yeah baby ... feed that algorithm! The damn thing is always frustrating me anyway. As for the rest, from my side I think jumping high amp circuits should always be done with utmost care. And with that in mind I think all readers should give good thought to jumping a car battery or connecting/disconnecting a large capacity battery bank. From my side I guess I bring it on myself but it seems I frequently get commenters whose expertise is beyond my own. As I see it, leaving positive for last either gets you an aggressive spark if any load present (car as example) or no spark if completely open circuit, while neg last rarely gives material spark either way. Let me know if you think I'm wrong.
Something to consider with your battery set up. I am currently having 1200AH of Victron 24V installed on our boat. Using Arco Zues regulator for the 24V alternator. Keeping the 2 AGM for the 150hp main diesel and the 13.5KW diesel generator. This is because 99% of LIFEPO4 batteries are not meant to start big diesels because they can not deal well with the massive 1100-1400 cranking amp draw on the battery. Lead acid are superior for this. We also are putting in 2 more AGM for the bow thruster for the same reason, as you found out. The LIFEPO4 cant handle the big outrush demand. I also wanted to be able to parallel to the starter batteries incase either of the starter batteries ever died which was how our old house bank of 6 big 8D 24v batteries was set up. I got in touch with Victron while we thought about the system and asked them about running the thruster and starters off the Lithium and they said clear as day they are not designed for that and it will void the warranty. I asked about an emergency situation where all lead acid were dead could you start the diesels and their answer was yes you could but they would only recommend it as an absolute last resort. The owner of Battle Born batteries did a youtube video and he clearly states not to use LIFEPO4 for starting, he goes on to say lead acid are designed for this purpose and are the best option available for it. There are not some LIFEPO4 that say they are designed for starting so i would say maybe use one if you want to experiment but again they are not designed for that use. If we did not need the 2 extra AGM for the thruster we could have fit 1600AH of the Victron 24V LIFEPO4 which i would have liked but im going to listen to the experts. So you are absolutly right when you say there is new info coming out but i see a lot of youtubers making the mistake of using the LIFEPO4 incorrectly and then complaining they need to replace one or two batteries after 6-12 months. This also creates a problem because then you have unbalanced batteries and some of the companies recommend replacing all at the same time so they stay within a certain range. The one big thing I wanted to avoid and why i researched this a lot was having the possibility of the boat electronics shutting off while maneuvering. If the BMS did not like the thruster use and we were in a situation where we needed to use it a lot to get on or off the dock in a strong breeze, imagine the whole boat going dead in the middle of trying to get in or out of a marina with dozens of other boats right next to you!!!! Did your system shut down with thruster use which led you to this change?
Okay, now we're getting to the meat of things. To start, I'd say that we do use (2x) isolated AC Delco Marine Voyager II M27C 1060 MCA / 850 CCA / 125 RC sealed lead acid start batteries for the main engine (Yanmar 88hp) and generator (6Kva Fischer Panda w/ Kubota Z482). Being 12V, these two batteries work through completely separate circuits and isolators, although there is a key-style bridge that allows both to be connected in parallel should one get run down.
Moving on to the house bank, our cells are EVE 280Ah (LF280) with an estimated number of lifespan cycles coming in at 3000 to 6000. Newer EVE cells, LF280K for example, are rated at 6000 cycles but at the same time, this number appears to have been the result of lowering the charge number from 1C to .5C. 6000 cycles would be over 16 years of lifespan assuming a full charge cycle each day, which we never do.
I think the key issue you've been focusing on is using LifePo4 batteries as start batteries. So in our case this is mute because we're not using them for that. However, the large discharge for the bow thruster/windlass needs to be looked at. Our supplier was Nee Electric in China, who sold us our BMS units (raw cells ordered elsewhere). They pointed to EVE's data sheet that stipulated max discharge numbers (1C), and from there it was a matter of making sure we had enough battery packs in parallel to meet or exceed that number. I chose 650A for the bow thruster since that was close to the number I was seeing with a clamp meter as thruster was activated. The amp draw would immediately drop to low 500A numbers, or even amps in the upper 400's. This is typical for large motors at startup. I chose 65A as my thruster number simply by taking the rated 1500W and dividing by 24. So the target is 715A, and we have 840A (1C of 840Ah) to use while still staying within EVE's safe working limits. Note that the issue is that while you can instantly discharge all 840A (safely I assume, since that's the number they list), LFP (LifePo4) can discharge way more than that if not controlled by the BMS. This is where the damage can get done, if you go past that number. With 900A of BMS, it simply comes down to throttling the discharge number to 280A per pack (or 840A total), using the Daly SmartBMS app on my phone.
On our first attempt, the fail was twofold. First, I had enough capacity at 840A to run the thruster/windlass, but under-purchased the BMS units to be 150A. Thus we had only 450A total capacity. The second fail was to enter 150A as max draw on each of the BMS's. This meant that the BMS actually cut out/went dead at 150A (its rated max). If I'd chosen 149A as cutoff the BMS units might have held, leaving the thruster to operate on less amps than it really wanted or needed. Not sure if that was good or bad, but something to think about. (I say not sure because running the thruster on reduced amps would eventually damage the motor. And I might not know this was happening. Therefore, critical to know what your draw is in real life).
So let's also address how this affected things during docking. Luckily, while all the electronics like radio, plotters, thruster, etc. went dead, our engine continued to run, so that was good. However, modern diesels are common rail with electronic emission controls. These engines may or may not run during a complete house bank shutdown. That said, if your panels and engine controls work off the 12V start battery, it's quite likely that this separation would mean continued 12V power and no impact to the engine. If it were me, I'd talk to somebody about safely testing such an event. Of course on my side I don't need to do that as I've already seen it in action aboard Talisman. I should add that thruster controls came back nearly immediately, but I quickly became wary of using the thruster and got pretty good at docking without it.
Finally, I never mentioned too much about it, but the Daly Parallel Pack Modules shown are an interesting gizmo. The concept is to balance charge and discharge (active balancing at the pack level) up to 15A between packs. Daly sucks at documentation, so getting good info on how this is accomplished is tough. However, as I understand it, when you need 715A, it kicks in to make sure this number is evenly distributed between the packs. This way you don't kick one pack off by maxing it before going to the next for more power. Whether it works that way or not, I do see nearly identical charge volts at +/- .004Mv, which is what we see at the individual cell level as well. You can set your active cell balancing targets in the SmartBMS app, and over the last season it worked extremely well.
So to wrap this up, I'd say that our install is an ongoing experiment. We never see elevated battery temps, and the Sterling ProReg DW external voltage regulator paired with Sterling APD (alternator protection device) seem to be working as we didn't see any adverse events with the alternator. Our Mastervolt Chargemaster 24/110-2 charger has also worked to perfection.
I should note one thing that is rarely discussed, and this is the time required to fully recharge a set of LifePo4 batteries. Having huge capacity means extended recharging times! I can go ten days without recharging our batteries, but doing so means running the generator for perhaps a full day to recharge. However, with that in mind, if we know we'll be in a marina for a couple of days we'll save generator time and just run the batteries down to 30 or 40%. Then, once we arrive we'll put the boat on shore power and let things come back up without worrying about it too much.
I'd appreciate any thoughts people might have on all this.
There are also extensive install notes in the episode description.
That is a lot of info with a bunch being above my pay grade but thank you for sharing and as i learn more i will revisit it. Testing to see what runs with a house bank shutdown is a good idea and we could easily simulate that. It would be good to know ahead of time for sure. To me it sounds like you know a lot more than any of the other youtube channels that i have seen install LIFEPO4 systems. My main goal was to less frequent generator use as we are switching the hot water heater over to battery and even though as you stated it does take a long time to fully recharge the LIFEPO4 house bank its still much faster than the 6 big 8D lead acids we had. So we effectively get about 2X battery power just due to 10-20% draw down threshold vs the 50% and we are adding capacity too so we end up at about 3x the old house bank. As you know the LIFEPO4 will take 200-300 amps almost all the way to full so charging will still be faster than the old house bank which could take 6 hours just to go from 90 to 100%. So less gen run time is less fuel burned, less frequent oil changes and most importantly less noise. As other systems age out ill look into 24V heat/ac and other big users we can move to battery. The one thing that i do not quite understand in the individual BMS vs a central BMS and which is better, to me it seems individuals would be better as long as they all communicate. Im looking forward to getting on the boat in a few weeks and seeing how everything works, and then eventually testing how long we can run with no generator. Thanks for your reply!!!@@SailingTalisman
just wanted to add you can get the LIFEPO4 system to handle the bow thruster but as i stated Victron warns against using LIFEPO4 in this manner, that is why we are adding two more AGM. We had enough capacity and could have put in a bigger BMS to handle the draw but we were directly told not to do that.@@SailingTalisman
@@ducatiparts966 As you say, 200-300 amps, but where does that come from? Short of adding multiple battery chargers, which I've never heard of doing, the biggest ones from Mastervolt deliver about 110A @24V (which would indeed be 200A @12V). And that will be a longer period of charging than you might think. Don't get me wrong, I'm in favor of adding as much capacity as you can afford and have room on the boat, but I predict that you'll wish you had more charging amps. This is the issue that many of us are bumping up against, which is that the alternators are the most dated of the technology in the chain.
there are 250-300amp alternators that will give you close to that capacity and you also have chargers and my understanding is you can stack chargers to get higher output as the LIFEPO4 will take a lot of amps. ill have more info as ill be spending a day with the installers to comission/test and learn the system in about 4 weeks.@@SailingTalisman
very cool project thank you for sharing!
Thanks Bob!
Lithium batteries under the floor is a bad idea. The first place for water to go with a leak or bad storm is under the floor. Losing all the battery power in a storm would be horrendous.
The Daly BMS is not great. A far better choice would be the JK bms. 200A with built in 2A active balancer.
Running the bow thruster through FET based bms is a risk. The easy fix is to wire the bow thruster and windlass from the engine battery. The engine will always be running when these devices are used. In addition, the engine battery can be kept fully charged with a DC/DC charger from the lithium. Charging lithium with alternators is a bad idea, especially with the Daly BMS. There is no interfece to shut down the alternator in the event of the BMS doing a safety shutdown. This will blow the alternator diodes. Far better to charge the engine battery with the alternator then use a high output DC/DC charger to charge the lithium. Rule of thumb on standard alternators is 50% of the alternator rating as a DC/DC rating to charge lithium
The location of the batteries was chosen by the manufacturer, and almost all sailboats use this location or something similar. This is because getting weight low and centered in a sailboat promotes stability at sea. Having your boat capsize because you changed the engineering of the design would be a problem too. The battery box we have is fiberglass coated wood with no penetrations below the waterline, and with an interlocking cover. There is no other locations that would house this much weight and volume. And a 200A BMS would be just as deficient as my 150A Dalys. We have three packs of 8 cells in a 3P8S configuration, so looking to supply a minimum of 650A for the thruster plus 65A+/- to the windlass, which is 715A min. Your plan shows 600A, while still being short by 115A, while mine delivers 840A (1C) with a true max of 900A (1.07C), which is okay under EVE's table of charge and discharge capacities. And we're never asking for more than 93% of the amp capacity of the BMS. As for internal switching, I can't worry myself about it. Over the 4 years that I've been studying lithium technology, I've seen hundreds of debates about this or that, and how this other thing will never work, etc., etc. In the end, the engineers at Daly or JK have to make their bet and stand behind it. I'll add that the Daly units I'm using have active cell balancing down to .001mA and active pack balancing (through the Parallel Pack Modules) up to 15A. As for charging with alternators, they work fine as long as you add a good quality external voltage regulator such as Sterling, or Balmar, or similar. New versions are coming on the market all the time, and they need to have temp probes for both the battery and alternator case (which ours has) in order to protect things if they start getting hot. But experience shows me that battery temp isn't a problem for us, probably because 1C charging would be 280A, which there's no way to even come close to that with a 100A alternator and 110A battery charger. It's the alternator that needs watching. And while DC/DC chargers are fine for small lithium batteries, the largest Victron 24V DC/DC charger is the Orion 24/24-17, which as the name implies is limited to 17A output at 24V. I had (4) of these run in parallel to try to meet the DC/DC plan, but it was a huge and expensive fail. Putting all those chargers together caused a voltage drop from 26V to 16V, which people complain about on the Victron forum and Victron refuses to address except by telling them to increase the cross section of their wiring (which doesn't work). Even if it all went to plan, you'd be limited to 68A going to the battery. Finally, I would advise readers to alter the main electrical plan of your boat or RV with care. The engineers usually knew what they were doing. For example, powering a 24V bow thruster and windlass off a 12V single lead-acid battery, while expecting the 12V alternator to pick up the charge current to balance an insane draw, is a bad idea from inception. I don't mean to be difficult, but the issue we all face is that this is a complex add to an existing design, and all the obvious solutions have some sort of fatal flaw.
@SailingTalisman in my opinion you are making your boat unnecessarily complex and highly reliant on electronics. You are then fitting those electronics in a bilge. The dampest part of the whole boat. Just because you boat was built with lead batteries in the bilge doesn't mean it's a good place for lithium and all the associated electronics. Lithium is way lighter than lead for the same capacity.
My boat was built with fuel and water tanks under the floor. Batteries live under the saloon seats, way above the bilge. The battery compartment is waterproof. It would take a serious flooding to soak the batteries and electronics.
We are a 24v boat. A far better set up than a 12v boat. New boats should be built as 24v now, but the manufacturers still churn out 12v boats.
We are not reliant on alternator charging. 920w of solar assists here. 2x 17A Orions are plenty for us.
We use electric cooking, heat hot water and run our watermaker off the lithium. 385Ah at 24v
It’s being my experience with hi current applications agm batteries are better than lithium an example is a winch with lithium cuts the bms off where agm same size battery has no problems running the winch’s
Hi BCM. This is part of what we've been discussing. Off the shelf, even budget priced Lead Acid, AGM, or Gel batteries will have huge Cold Cranking Amps, often well over 1000A @ 12V. But their ability to be drawn down below surface discharge will be poor. The batteries will be ruined and won't hold a charge anymore if run down to dead a few times. Even deep discharge marine batteries won't hold a usable charge anything like LifePo4. They'll drop below rated voltage about halfway through the discharge curve (Google LifePo4 vs Lead Acid discharge curve to see this graphically). If you've got a Jeep or ATV that has the engine running and is producing alternator amps to keep the battery charged, then Lead Acid or AGM will be perfect. But for people on boats, especially, where Amp Hours are most important (the length of time you get usable voltage and amps), then Lithium/LFP/LifePo4 come into their own. With LifePo4 packs you need to check the mfr. data sheet very carefully. Typical discharge limits tend to be 1C, or 1x capacity. If you had a 100Ah LifePo4 drop-in battery (ie. a battery that looked like a normal car battery, with all cells and BMS inside a plastic case with two external posts), you'd be seeing 100A @ 12V, typically. There's no way that's going to power a winch for very long. I don't know what an off-road winch draws, but I do know that our windlass draws about 65A, and possibly 100A at 24V full draw (we're a 24V native boat). Converting to 12V that would be 130A and 200A, respectively. And as you get to larger discharge amps for Lithium, the batteries will get huge. As for Lithium cutting out, this doesn't always happen because you hit the discharge amp limit. It can also happen if the BMS is too small for the draw, or if it overheats. BMS's will also cut out if the battery cell temp gets too hot, but that doesn't usually happen immediately. I suspect, but do not know for sure, that larger "budget" drop-in batteries will not be able to deliver the full rated load due to BMS units that cannot take the discharge amps being drawn. In our case, that was exactly what was happening when I chose a 150A BMS (total 450A for 3 battery packs combined). Between the bow thruster and windlass (they might be needed simultaneously) I was drawing perhaps 715A, at least for the first few seconds when the thruster motor was drawing max amps. And you can see from the footprint of our battery bank how much LifePo4 is required to provide that kind of discharge amps. Just to review, 24V is half the amps of 12V (this is good) and we have 840Ah of capacity. Our 3x 150A BMS were allowing us 450A out of the 840A available. The new 300A BMS units now allow 900A of discharge capacity. This is necessarily more than 1C (840A) which is EVE Battery (brand) recommendation for max discharge. So I manually entered 280A for each BMS as max discharge on the SmartBMS phone app that Daly uses. Remember that Amp Hours and Discharge Amps are not the same thing. That's why they tell you 1C, since 1C means 1x Capacity. Does that all make sense?
I here people talk of the dangers of propane on their boat. They move to induction, replacing a solenoid and a few hand valves. Then they layer: solar, alternators, generators, Lithium, massive wiring and management systems. Not saying it is bad if done right, but there is something to be said for simplicity v. Risk.
That's one of the most inciteful things I've read in a while. Well done! It's funny how so many of us, including myself obviously, do exactly as you say. And it's got me thinking, is this just a human thing of making our house a better place to live? Is this what it takes to attract a mate? Or are we beavers, created with an instinct to improve what we see? How about economics? There are a ton of older boats like ours that came kitted out with ancient electronics. Nothing that some investment and elbow grease won't get fixed? Who knows. What are your thoughts?
Instead of Maslow’s hierarchy of needs, I think there needs to be a Kelley’s sailing hierarchy of needs. Once you get past the physiological, safety and security needs, you move into the mission requirements, technical capability, and personal satisfaction arena. Mission requirements for a coastal cruiser are not nearly as steep as someone who crosses oceans. I think the problems arise from understanding what you want, but not knowing what the hell you are doing, or you don’t know what you want but have the capability and do it anyway. If you know what you want and have the capability have at it!@@SailingTalisman
@@SailingTalisman Instead of Maslow’s hierarchy of needs, I think there needs to be a Kelley’s sailing hierarchy of needs. Once you get past the physiological, safety and security needs, you move into the mission requirements, technical capability, and personal satisfaction arena. Mission requirements for a coastal cruiser are not nearly as steep as someone who crosses oceans. I think the problems arise from understanding what you want, but not knowing what the hell you are doing, or you don’t know what you want but have the capability and do it anyway. If you know what you want and have the capability have at it!
I think we're coming close to doing all the things we need to in terms of improving the boat. Talisman is a 30 year old boat, but is also something akin to a 69 Camaro in that she is still sought after as a truly capable offshore cruiser. For this reason we've been making the investment to bring all her systems up to modern day spec. From here on out, new gear will likely be the normal wear and tear you see when using a boat for its intended purpose.
Is BMS just for lithium - would one use them for AGM batteries? Thanks for sharing your knowledge Kevin!
Hi Patrick. BMS boards are only required for Lithium style batteries. This is because the technology is not self-regulating, like typical lead-acid, AGM, or Gel. When I say self-regulating, I mean that LifePo4 chemistry similar what we're using is like a horse left alone with a trash can full of oats. The batteries will never stop charging on their own and will eventually melt down. You need an external control board to monitor all the variables. But once you've put the system together it is truly something to behold.
@@SailingTalisman thank youl Kevin
On a boat keep it as simple as possible lithium batteries are just to complex. If they get to hot big problems can happen.I will stick with AMG batteries.
Hi Bob. Use drop-in LFP batteries. It'll save you half the wiring complexity. In another decade AGM, Gel, and to a lesser degree lead-acid will become unavailable as everything less than LifePo4 is quickly becoming legacy technology in the industry. In closing, it's pretty sweet to go from daily charging to charging every 3 days (with option to go to 10, just would require longer charging to get back to full).