Building my own LifePo4 lithium bank

[Dafaseles]

Hey, I'm hoping to pick some people brains here that have built their own lithium banks.
My buddy has a 2019 GMC Terrain. We are currently looking into getting him a high output alternator, so I'm not sure what the output will be. Being that it's only a 1.5 liter 4 banger, I'm sure the options will be limited.
He's trying to power a "6000"ish watt system.
I was thinking 40ah of headway cells (the buss bars I was looking at are for 20 cells. Says it's for 40 ah https://coventryind.com/product/headway-battery-40-ah-buss-bars ). Are there better buss bars? Will this even be enough given the alternator probably won't be a super high output.
Looking into the actual cells, I see them in 8ah, 10ah, 15ah, and 17ah. How much of a difference to the different cells make? Am I looking at the wrong ones? https://www.evlithium.com/Headway_Battery/
I know I also need a balancer. Anyone have a website I can order a good one off of?
I know this topic has been beaten into the ground. Hopefully someone can point me in the right direction.

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[hispls 5,000+ posts]

Trying to run 40AH in this application would be pushing those cells to their absolute max ratings and probably beyond if you're getting an upgrade alternator. I'd double that to be safe or triple that if you want to get a decent life expectancy out of your cells. That's assuming you're using the common 8AH cells, larger capacity cells may have different charge and discharge ratings.

 

[Dafaseles]

Trying to run 40AH in this application would be pushing those cells to their absolute max ratings and probably beyond if you're getting an upgrade alternator. I'd double that to be safe or triple that if you want to get a decent life expectancy out of your cells. That's assuming you're using the common 8AH cells, larger capacity cells may have different charge and discharge ratings.

I was thinking headway cells because of the charging voltage. But you think ying- long would be a better option? Or do you just mean using more cells?
And more ah? Like 120?

 

[hispls 5,000+ posts]

I was thinking headway cells because of the charging voltage. But you think ying- long would be a better option? Or do you just mean using more cells?
And more ah? Like 120?

Not sure what you're paying on the headway cells, so they might be OK, but their nominal charge rating is 3C (3x your amp hour rating) so if you get say a 200A alternator you're probably going to hurt those batteries if you don't have more like 80AH. They claim you can charge them harder under the right temperature conditions but personally I'd plan around being safe to operate in any condition as opposed to having to make sure the temperature is within a certain window so you don't destroy your cells.

Max continuous discharge is supposedly 15C which leaves you at 600A draw out of a 40AH bank which should just about cover your 6000W amp but you'd be running them really hard.

Bear in mind the further you go beyond those nominal rating the worse you can expect your cycle life to be below published.

I'm personally a big believer in LTO, but the headways should function if you size your bank appropriately and if you're getting a decent price.

 

[Dafaseles]

Not sure what you're paying on the headway cells, so they might be OK, but their nominal charge rating is 3C (3x your amp hour rating) so if you get say a 200A alternator you're probably going to hurt those batteries if you don't have more like 80AH. They claim you can charge them harder under the right temperature conditions but personally I'd plan around being safe to operate in any condition as opposed to having to make sure the temperature is within a certain window so you don't destroy your cells.

Max continuous discharge is supposedly 15C which leaves you at 600A draw out of a 40AH bank which should just about cover your 6000W amp but you'd be running them really hard.

Bear in mind the further you go beyond those nominal rating the worse you can expect your cycle life to be below published.

I'm personally a big believer in LTO, but the headways should function if you size your bank appropriately and if you're getting a decent price.

As far as price goes, I don't have any specific place to buy anything. So any help with that area is greatly appreciated as well. Really, it comes down to getting it done right and safe over any kind of price.
It's been my understanding that if I were to go LTO, where they are more stable and safer, I would need to charge at 15+ volts. If I'm not charging at that high of a voltage, you would still recommend LTO (which I have absolutely no problem with)? I mean, safety is #1.
If I went LTO, what cells would you recommend? I only know about ying- long. Again, price is really the last thing I'm worried about. I just want to accomplish this with quality components that will last.

 

[hispls 5,000+ posts]

As far as price goes, I don't have any specific place to buy anything. So any help with that area is greatly appreciated as well. Really, it comes down to getting it done right and safe over any kind of price.
It's been my understanding that if I were to go LTO, where they are more stable and safer, I would need to charge at 15+ volts. If I'm not charging at that high of a voltage, you would still recommend LTO (which I have absolutely no problem with)? I mean, safety is #1.
If I went LTO, what cells would you recommend? I only know about ying- long. Again, price is really the last thing I'm worried about. I just want to accomplish this with quality components that will last.

LTO is basically just a different flavor of LiFePO so either should be safe as far as not exploding or catching fire or whatever.

As you say, LTO does start with an oddball voltage so you can either use 5S bank and charge 14.0-14.2 or 6S and optimally charge at 15.0-15.5. That said, I've been running YingLong banks for a few years now on just 14.4-14.8 systems in my Jeep and my brother's Civic and both are still performing fine. I'm already to the point where if they died tomorrow I'd only have to replace the cells and not all the copper/hardware/busing and would still be way ahead of the game vs if I'd bought AGM that would do the same job. Mind you, I've been doing big builds for long enough that the cost of a giant battery bank every few years is sort of something I expect and budget.

YingLong 40AH is a good option because they've been widely used in car audio for a little bit now and there are some good off-the-shelf busing options. There's a couple other brands of cylindrical cells coming out of China that seem promising but cost isn't great and ready made bus options aren't going to be easy to find. I've also got some Toshiba cells here that have some really good looking specs and I have high hopes for. I haven't tested the Toshiba much beyond just a 5S bank I put in my 4 wheeler last fall and you'd definitely need to custom fabricate bus bars for those.

Not sure who is a reliable seller here in the USA. I've got some cells here I've been meaning to put up in the classifieds section, but check around. Also worth mentioning, I see a few guys in this area using C-Max cells with good results though I think they have a trusted source who is scrapping them out of new-ish EV banks.

 

[Dafaseles]

Yeah, the only ying-long cells I can really find online are the XS power ones in various car audio websites. Which is fine by me, if I can't find a less expensive, legit cell. It is what it is.
They come in packs of 6. So I'd have to buy 2 packs. So far I'm looking at Jim's buss bars, but I'm still looking, see what's out there.
Custom electrical service has an LTO ready 6s balancer.
Should I run 12 cells? I assume if 6 cells is 40ah, 12 would be 80ah? And I would do 6 rows of 2? (I know that's not the correct way to explain it, but it's 5 am. I can't think straight yet lol).
Does this sound correct? Would this be able to power a "6000" watt system and a car safely? And charging them at below 15 volts is still fine? I have to look into the Terrains charging system, but if it's like mine in my Silverado, it starts cold at 15.3ish volts, then can drop down into the 13's and fluctuates given the charging needs.