4 x 200 AH LiFePO4 Parallel Installation Cell & Battery Voltages

[RV Steve]

I bought 4 x 200 AH Feence LiFePO4 batteries on eBay which arrived Wed. 11/13/24. I own 2 NOCO Genius 2600 chargers. Batteries all arrived at 52% SOC so I charged them using the "12V Lithium" profile which is supposed to charge at 14.2 volts. Both chargers ran at around 13.5 volts; my older charger ran at 10 amps the newer charger at 13 amps. The batteries have JBD Bluetooth BMS model: JBD-SP04S034L4S200A on all 4 batteries and I'm using the Overkill Solar App. I finished charging the batteries to 100% SOC between the evenings of 11/13 and 11/14/24. The batteries have rested since then not hooked up to any loads. I was worried about the low charging voltage and found a good article at:

https://panbo.com/charging-lifepo4-whats-the-impact-of-lower-voltages/

I'm not sure if the batteries are ready to hook up in parallel or not. Here are my stats as of today:

#YZP24072516: 100% SOC resting voltage 13.35 volts 204.0 AH of 205 AH; Cells 1 - 3.338 V 2 - 3.338 V 3 - 3.340 V 4 - 3.340 V
#YZP24071800: 100% SOC resting voltage 13.35 volts 206.0 AH of 207 AH; Cells 1 - 3.338 V 2 - 3.339 V 3 - 3.343 V 4 - 3.338 V
#YZP24072096: 100% DOC resting voltage 13.33 volts 208.0 AH of 209 AH; Cells 1 - 3.332 V 2 - 3.333 V 3 - 3.333 V 4 - 3.334 V
#YZP24071800: 100% SOC resting voltage 13.35 volts 206.0 AH of 207 AH; Cells 1 - 3.338 V 2 - 3.338 V 3 - 3.343 V 4 - 3.338 V

I haven't touched the BMS settings. The factory setting for balancing on all 4 batteries are: start voltage 3300 mV delta to balance 15 mV Balancer Enabled is on and Bal. only when charging is on. All of the cells are above the starting voltage but below the delta. I didn't observe any cells balancing on the app.

Once installed these batteries will be charged by solar two arrays. Each is 2S3P Renogy 100D panels run through Victon SmartSolar MPPT 150/60 controllers. I hit 48 to 50 volts array voltage daily since it's cold here. I have a pair of busbars for the parallel connections and a second pair of busbars to use for load connections. I currently have the solar charging system hooked up to my 6.5 year old pair of FLA Crown CR260 batteries. I am also in a RV park with full hook ups so I have time to get things right.

Do my battery and cell voltages look close enough to go ahead with the parallel hook up?

I am a rookie LiFePO4 owner and any input is welcomed! My prior trailer had 300 watts solar with Schneider C40 controller and Bogart Engineering monitor with shunt. I'm setting this one up with a Victron SmartShunt and will add a Multiplus 12/3000/120-50 120V in around a month.

 

[robbob2112]

Here is a thread with a design for a 4p set of batteries --- note - I did the diagram from what was being thrown back and forth

https://diysolarforum.com/threads/robbob2112-answer-thread.84402/post-1100257


Your voltages are close enough to hook in parallel.

Make certain to fuse each battery either at the post or in the positive line.

so 12.8v at 800ah = 10240Whrs

Typical 5 hours of sun per day in the US

10240Whrs / 5hrs = 2048w -- this is the minumum watts of solar panels you need to charge your bank from empty to full in a day.

From the manual you can only poke 860watts into the MPPT and get it to the battery - you would need a minimum of 3 of these in parallel




600w of panels (2p3s) won't get you there --- 2p4s --- and repeat 2 more times for a total of 2400w --- or get bigger panels.


And, the NOCO chargers are notoriously bad at charging LFP batteries - the Lithium profile seems to be half between lithium Ion (NMC) and lead acid AGM ... If you intend to charge with wall power on a regular basis better to get a dedicated LFP charger.

 

[HRTKD]

If you intend to charge with wall power on a regular basis better to get a dedicated LFP charger.

Once the Multiplus is added to the system, he'll be good.