Battle Born with Ampere Time LiFePO4 batteries in parallel ?

[luisenriquereyes]

I currently have two 12V Battle Born 100AH batteries connected in parallel.

I want to add another two in parallel but they are 12.8V Ampere Time 190AH batteries. Is it safe to do so?

 

[timselectric]

Yes
Just make sure that the voltage is close when you connect them. (Within 0.5v is best)

 

[Steve_S]

You can add as many batteries in Parallel to a Battery Bank with few issues "In General".
Some things to consider when doing so:

• Ensure the Battery Cables used are identical in Gauge & Length to the Busbars.
• Use GOOD Busbars capable of handling all the amperage potential such as these: https://www.amazon.com/Pike-Industries-Copper-Busbar-Terminal/dp/B08JKXKF3Q/ or from BlueSea etc... Keep away from the chrome plated Chinese Cheapo's !
• Ensure that each battery is FUSED appropriately. 200A Fuses are acceptable in such an application. MRBF Fuses can be hung directly off a proper busbar like the Pike's. https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A

Some gotcha's !
- Ensure the Batteries are Near Identical voltage when connecting them to the Common DC Bus ! Otherwise the lower voltage batteries will draw from the higher voltage and the greater the difference the greater the draw to Backcharge.
- Different Capacity Batteries are OK "to a point" as this affects charging: the smaller will charge up to 100% SOC first and then goto rest mode while the larger batteries will continue taking charge. THIS IS FINE ! You will see the different batteries taking charge (in Amps) proportionate to their capacity
- During Discharge, you will also see them discharging Proportionately relative to capacity. This is Normal. IE, a 200AH Battery will discharge & service loads at near double the rate than a 100AH Battery.
- They will remain nearly identical in voltage while within the Working Voltage Range of 3.000-3.400 Volts per cell. Once you reach below 3.000Vpc (12.0V for 12V system) the larger batteries will try to backfill the smaller battery, this is NOT heavy but does reduce overall capacity due to some losses along the way. IF less than 50AH difference, it is barely noticeable,, IF 100AH or more, then it is noticeable.
- NB ! Each battery IS independent and the BMS' will not interact or interfere with each other, unless they are programmed differently, IT IS IMPORTANT to match the settings for cutoffs, etc...

SPECIAL NOTE for Solar Charger Controller or External Charger (incl Inverter/Charger) If they have a programmable EndAmps/Tailcurrent, calculate the EndAmps for both Batteries sets and split the difference. 100AH X 0.05 = 5A, 190AH X 0.05 = 9.5A, so your EndAmps would be 7.25A. Used by ABSORB as Absorb Ending Amps to switch to FLOAT Mode (Constant Voltage/Variable Current).

I happen to be using a varied Bank which includes: 1x 24V/105AH, 2x 24V/174AH & 3x 24V/280AH for 1293AH/33.1kWh.
These all use identical JKBMS', 4/0 Cabling & MRBF fuses in a Split Bank format.

Hope it helps, Good Luck.