How many amps via charger is needed for 25 100ah lifep04 batteries?

[lt170chevelle]

Ok Im currently up to 25 lifep04 100ah 12v batteries on my off-grid battery bank and just added a 4k generator and a recpro 125 amp charger.
I've read you generally want to stay roughly below 30% of the amps of the battery.
So at 2500ah of battery capacity, am I correct on needing around 700ish amps of charging, or maybe 5 of the 125a chargers for the safest quickest charges. Or am I all wrong on this thought? I don't want to over do it, nor under do it. ?

 

[sunshine_eggo]

Ok Im currently up to 25 lifep04 100ah 12v batteries on my off-grid battery bank and just added a 4k generator and a recpro 125 amp charger.
I've read you generally want to stay roughly below 30% of the amps of the battery.

LFP has a maximum charge rate. The minimum is whatever you can tolerate.

Difference manufacturers recommend different rates. 0.2C is common.

So at 2500ah of battery capacity,

Assuming perfect balance, 2500Ah of LFP can typically be charged at UP TO 1250A.

am I correct on needing around 700ish amps of charging, or maybe 5 of the 125a chargers for the safest quickest charges. Or am I all wrong on this thought? I don't want to over do it, nor under do it. ?

Your 4kW generator is limited to 4000W output or 4000W * .85 / 12A = 280A

And you really don't want to run the generator more than 70-80% rated, so about 200A is a good target charge rate for your generator.

 

[400bird]

Why did you start another thread?

There's no idea amount of amps to charge any lithium battery. You need enough amp hours to recover what you have used previously.

Scratching my head wondering why the solar isn't keeping up.

Hello, new guy here. Been off grid for over a year now on my ever expanding solar setup. Been trying to figure out if my system just is not big enough or something else. Like most beginners I have mostly cheaper end equipment. Would like to here any input or advice on this setup on why it isn't...

diysolarforum.com

 

[lt170chevelle]

Why did you start another thread?

There's no idea amount of amps to charge any lithium battery. You need enough amp hours to recover what you have used previously.

Scratching my head wondering why the solar isn't keeping up.

Hello, new guy here. Been off grid for over a year now on my ever expanding solar setup. Been trying to figure out if my system just is not big enough or something else. Like most beginners I have mostly cheaper end equipment. Would like to here any input or advice on this setup on why it isn't...

diysolarforum.com

Just wanted to post this question in the battery section is all. Some forums are particular on thread placement from past experiences and wasn't sure on this one.

 

[lt170chevelle]

LFP has a maximum charge rate. The minimum is whatever you can tolerate.

Difference manufacturers recommend different rates. 0.2C is common.



Assuming perfect balance, 2500Ah of LFP can typically be charged at UP TO 1250A.



Your 4kW generator is limited to 4000W output or 4000W * .85 / 12A = 280A

And you really don't want to run the generator more than 70-80% rated, so about 200A is a good target charge rate for your generator.

Thanks I wasn't sure . I figured since it had a 30amp outlet and that the 125a charger is rated at 8 amps input I figured I could run three safely , but I think I'll take your advice and stick with two for starters. The one charger is extremely slow to charge the bank.

 

[sunshine_eggo]

Thanks I wasn't sure . I figured since it had a 30amp outlet and that the 125a charger is rated at 8 amps input I figured I could run three safely , but I think I'll take your advice and stick with two for starters. The one charger is extremely slow to charge the bank.

Don't confuse AC/DC input/output amps. They're not the same.

30A of 120VAC is roughly 300A of 12VDC

 

[DIYrich]

700 amp requires a pretty big wire.
All in parallel?

 

[MisterSandals]

For some reason this thread reminds (scares) me like this:

 

[400bird]

Just wanted to post this question in the battery section is all. Some forums are particular on thread placement from past experiences and wasn't sure on this one.

You'll find this forum is pretty tolerant of that, put questions where ever. I think many just look through the list of new posts.

Doubling up and having two threads on nearly the same question set will get two separate sets of eyes, each having different portions of the system information provided by you, and may come to different solutions as one may have info the other doesn't.

I guess this thread is a distinct question from the other, I'll just move on.

 

[sunshine_eggo]

I'll jump in and say, don't cross post. It's a dick move. Even with different perspectives, there is a huge overlap of duplicated information thus wasting the time of those responding.

Cross post means making an identical or highly similar post in different categories.

I don't regard this thread as a cross post of the other.

 

[sun_of_a...]

I'll jump in and say, don't cross post. It's a dick move. Even with different perspectives, there is a huge overlap of duplicated information thus wasting the time of those responding.

Cross post means making an identical or highly similar post in different categories.

I don't regard this thread as a cross post of the other.

I did that a few days ago, cross post, for same reason as chevelle. Sorry, point well taken, won't do again.

By the way, Mr. Sandals link to 100 car batteries wired in parallel is worth the watch. I'd sure rather see such 12v 'welding and pyrotechnics' on video than in my own battery bank. A cautionary video.

 

[sunshine_eggo]

I did that a few days ago, cross post, for same reason as chevelle. Sorry, point well taken, won't do again.

By the way, Mr. Sandals link to 100 car batteries wired in parallel is worth the watch. I'd sure rather see such 12v 'welding and pyrotechnics' on video than in my own battery bank. A cautionary video.

Yeah. I saw that video about a month back. Nuts!