I'm in central Florida, so cold isn't really a thing. 120+ In-car Temps are a thing tho.
I still can't figure out LTO vs LiFeP04. I know the voltage difference, but I've seen LTO punctured and not catch on fire so that sounds better to me. I cannot run my voltage above 14.8 or my car will throw a tantrum so going with a 6s pack is a no-go. I will have to double check my cold start voltage, but I beleive it is 14.3. Whatever I buy will get used until I switch cars or upgrade my system again(hopefully never). I guess this has turned into batteries or alternator for the moment. Is a 320a alternator from mechman(assuming it will fit) better than 40ah of LTO or 48 ah of LiFeP04 for daily use? I might be able to stretch it to 80ah of LTO if you have em or 60ah of LiFeP04 from the pre-built guy.
Matt
Charge current is limited by the particular cells rating the red 38120hp headways cells have a charge current of 10c. This means 32a can handle 320amp
Lto normally is larger in individual cell size and capacity and typically has higher c rating for charge and discharge.
Lto is hands down the better battery, but if you aren't charging above 15v you may as well keep to lifepo4. Lto float voltage is 14.4v in 6s so you need to charge higher to effectively top the battery off rapidly during transient music.
Without looking at cells or ah we can see the power difference using ohm law.
Lifepo4
500amp×13.8v float=6900w
Lto
500amp×14.4v float=7200w
And both chemistry will hold slightly higher voltage. But the LTO has the advantage of starting higher
Lifepo4 will charge to 14.6v and will drop to 13.8v before voltage hits a brick wall. It will hold 13.8 much better than agm. It can hold higher voltage but that's the point in which the battery is fully in use.
Battery ah need depends on individual cell rating.
Say you need 500amp (500amp×13.8v=6900w) to support your goal headway cells are easy 500amp÷10c rating=50ah you can subtract the agm ah and the alt amp rating from the amp draw rating.
500amp-120amp alt=380amp
380amp-80ah agm= 300amp
300amp÷10c= 30ah lithium bank.
I'm using headway cells for this equation as I believe they are the best for your situation. I also don't like counting the agm into the equation and perfer to take 20amp off the alt for just running the cars systems
As stated before I'd suggest a 48-56ah headway setup.
Lifepo4 is just as safe as lto. They aren't prismatics or pouches. That is why I only suggested these 2 chemistries. Cmax cells are great but they are much more dangerous.
batteryhookup.com
