Do you need to balance Lifepo4 batteries in series?

[Riley]

Yes; however, you should actually connect across both parallel batteries, one pair at a time as shown:
View attachment 78437

Charge the lower pair at the circled points and then the upper pair at the circled points. You don't need to disconnect anything.

You should also power down the inverter until both pairs of 24V have been fully charged. You don't want to input additional charge or extract any capacity from either set.

Would it be fine just charge one battery on each set and let them balance?

Yes; however, you should actually connect across both parallel batteries, one pair at a time as shown:
View attachment 78437

Charge the lower pair at the circled points and then the upper pair at the circled points. You don't need to disconnect anything.

You should also power down the inverter until both pairs of 24V have been fully charged. You don't want to input additional charge or extract any capacity from either set.

Thank you!

 

[sunshine_eggo]

Would it be fine just charge one battery on each set and let them balance? Its much easier and le

Thank you!

No. If you just connect to one battery, you don't get balancing in the same way as you would if you ensure the current is passing through both battery as equally as possible. The only complication I could see is if your 24V charger leads couldn't reach.

 

[HARG Hunter]

Kilovault makes a 48v balancer for 4S of 12v batteries. Unit works for both LFP 12v and lead acid 12v.

KiloVault Battery Balancers

KiloVault Battery Balancers help extend the life of a battery bank in your solar power system. 24V and 48V versions are used to maintain battery voltages across a series connection of batteries.

www.altestore.com

Glad I found this thread.
Just bought (4) CHINS 12v100ah LifePO4
I plan to wire them in series to get 48v, but I need to balance them.

Better off wiring them in parallel first and charging them together or just getting the balancer and hooking them up to the SCC?

 

[rmaddy]

Better off wiring them in parallel first and charging them together or just getting the balancer and hooking them up to the SCC?

Get all 4 batteries to the same SOC before you put them in series. So putting them in parallel and charging them together at 12V is a good plan. You should actually fully charge each one separately first before putting them in parallel. It's not a good idea to put batteries with big voltage differences into parallel.

 

[HARG Hunter]

Get all 4 batteries to the same SOC before you put them in series. So putting them in parallel and charging them together at 12V is a good plan. You should actually fully charge each one separately first before putting them in parallel. It's not a good idea to put batteries with big voltage differences into parallel.

Any suggestions for a simple charger to accomplish this?
My current charger only handles FLA, FLA and AGM, not lithium.
Thread searches seem to be a little overwhelming.

 

[codfish]

Any suggestions for a simple charger to accomplish this?
My current charger only handles FLA, FLA and AGM, not lithium.
Thread searches seem to be a little overwhelming.

An AGM setting should be OK. Stay away from a FLA setting.
The Chins should disconnect if they got to high, but a standard Agm voltage shouldn’t. But they might disconnect anyway from their own internal imbalance at a much lower voltage. The Agm setting will eventually try to float the batteries at a higher voltage than you would normally use for LFP, but for occasional use should be fine.
I’d watch the voltage once the pack got to 13.6v, it will go up Fast from there.

 

[HARG Hunter]

An AGM setting should be OK. Stay away from a FLA setting.
The Chins should disconnect if they got to high, but a standard Agm voltage shouldn’t. But they might disconnect anyway from their own internal imbalance at a much lower voltage. The Agm setting will eventually try to float the batteries at a higher voltage than you would normally use for LFP, but for occasional use should be fine.
I’d watch the voltage once the pack got to 13.6v, it will go up Fast from there.

Thanks. It is indeed a smart charger as well, so it will shut off. I'll have to see what the settings are.
It's a Viking 2/8/15a charger.

 

[codfish]

Thanks. It is indeed a smart charger as well, so it will shut off. I'll have to see what the settings are.
It's a Viking 2/8/15a charger.

The gel setting would likely be even better than Agm.

 

[sunshine_eggo]

I would try to get the specific voltages. GEL often has a lower absorption than AGM but a higher float. In most cases, when forced to choose, I have found AGM to be closest to the desired 14.4V absorption and 13.6V float.