Best Rv batteries

Itinerant1

how big/ many ampHrs is you Battery bank

Almot wrote:

Itinerant1 wrote:

Last thing when advising to use 90-30% or 80-20% or whatever % how about putting that in voltages I'm curious to see what you would actually set your parameters to. We are talking about Lifepo4 cells so it should be easy to figure this.
*If* you have perfectly matched cells.

To whatever the curve says it's 30 or 80% for your particular battery. Perfectly balanced at 80% they may or may not be, depends on (usually undisclosed) behavior of particular BMS.

Okaaayy...I'll give you a rough idea though, 80% is roughly 3.45v (13.8v) & 30% roughly 2.95v (11.8v).

This is using 3.65v (14.6v) as 100% seeing that no one recommends going over that and you see dropins using 14.4-14.6v as the balance voltage which also reset the 100% capacity display. Which I think we agree is a little high with no benefit.

I've been using 14.1-14.2v (87-90%, "my 100%" on the display) which keeps the cells fairly close in balance and enough to reset the SoC to match the batteries. The lowest I've seen and recorded after 3-4 days of living off the batteries is 3.20v (12.8v) with the inverter showing 12.5v drawing 144a. That would be 55% of battery bank but my SOC showing 30%.
I'm comfortable with that depth of Disharge before I start thinking of hooking the generator up if no sun is in the forecast.

Using roughly 40% capacity of the bank and staying out of the shoulders/ knees is still easy in an fractional C life of rv living.

Itinerant1 wrote:

Last thing when advising to use 90-30% or 80-20% or whatever % how about putting that in voltages I'm curious to see what you would actually set your parameters to. We are talking about Lifepo4 cells so it should be easy to figure this.
*If* you have perfectly matched cells.

To whatever the curve says it's 30 or 80% for your particular battery. Perfectly balanced at 80% they may or may not be, depends on (usually undisclosed) behavior of particular BMS.

Almot wrote:
2oldman, BMS does protect from severe overheating, among other things.
What it doesn't "know" is that cycle life shortens significantly when running 10-99% cycle and/or using it (or even storing) at temps over 85, getting progressively worse all the way to 132.
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Heat and cold isn't that big a deal if you plan accordingly during installation. Having a way to see cell temps and voltages is a plus. During the past 3 summers seeing ambient temps up to 90-95 I have not seen a cell temp above 80f, 65-75f cell temps seems to be the norm during summer. These are in a front compartment with no special cooling.
With cycle life claims of 2,000 of actually using the entire stored energy of the battery or 4-7,000 cycles with psoc(only time will tell). If you lost a little life out of them will you actually notice?
If a person can't figure to get out of 132f temps the battery is the least of the problems. ;)

Last thing when advising to use 90-30% or 80-20% or whatever % how about putting that in voltages I'm curious to see what you would actually set your parameters to. We are talking about Lifepo4 cells so it should be easy to figure this.
*If* you have perfectly matched cells.
3.65 (14.6v)
3.60 (14.4v)
3.55 (14.2v)
3.52 (14.1v)
3.50 (14.0v)
3.45 (13.8v)
3.40 (13.6v)
3.37 (13.5v)
3.35 (13.4v)
3.30 (13.2v)
3.25 (13.0v)
3.20 (12.8v)
3.15 (12.6v)
3.10 (12.4v)
3.05 (12.2v)
3.00 (12.0v)
2.95 (11.8v)
2.90 (11.6v)
2.85 (11.4v)
2.80 (11.2v)
2.75 (11.0v)

Almot wrote:
cycle life shortens significantly when running 10-99% cycle and/or using it

I usually run 60-99.

Yeah some politicos would rate George Washington and Abraham Lincoln way down the list from their precious selves.

"PORK! THE OTHER WHITE MEAT!"

"Rated number ONE by Payusandwe'llclaimblackiswhite Fibbers & Asssociates"

Trojan's forklift grade batteries are excellent. Compare group 31's and the gap widens a lot

2oldman, BMS does protect from severe overheating, among other things.
What it doesn't "know" is that cycle life shortens significantly when running 10-99% cycle and/or using it (or even storing) at temps over 85, getting progressively worse all the way to 132.
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Mex, not undisputed. Trojan isn't nearly as impressed of course.

https://www.trojanbattery.com/pdf/S600_6CS17P.pdf

Undisputed "Best Quality" flooded lead acid battery

Almot wrote:
all those other things that I mentioned, affect Li lifecycle - a lot. Hot temps are about as bad as running 10-99 cycle.

My BMS protects against high temps, and I can charge up to 131F. I don't know what yours does.