Battery Interconnects

[jmccrary]

Hello everyone! Been researching and trying to figure the answer to this out; however, I cannot. As each document someone has or video watched leaves out one step, the wire size of the interconnected batteries.

Here is what I will be doing:
2 - 2.4wkh AIO inverters (MPP 2424)
4 - 24v 100ah batteries

The manual for the inverts state a 125A fuse between the batteries and the inverter...which makes sense (2400/24*1.25)
The manual then states to run the inverts in parallel, to have 400ah on the batteries and the bank connected to both inverters...ok, do the math again (4800/24*1.25 = 250ah)

Since the 250ah is the max, should I gauge the interconnection on this figure, or the max amp hours of the battery bank (400, well 500 since the 1.25)?

My assumption based on what I can find (which is nothing really) would be the max current, so 250ah or 4/0 wire.

Second question, the batteries will connect to a busbar and then from the busbar to the inverter, I would go with the wire for 125a, 1/0 (the manual says 2agw).

Thanks!

Justin

 

[Mattb4]

From each battery to your busbar could be 2 awg welding cable (Temco - Max amps 205). Also from your busbar to your AIO's can be 2 awg. This is where you place a fuse and a breaker for each AIO. (if desired for isolation). Your bus bar must be able to support at least the 250a and likely you should get a 300a one. Since the batteries are splitting up the work of supplying the max 4800w of the combined AIO's each of them, if equal, would be pulling 1200w or 50a. I assume your BMS allows 100a per battery so that works out.

Also you might need a method of pre-charge.

ETA: It would be handiest to have a 6 bolt busbar each for positive and negatives. 4 for the batteries and 2 for the AIO's. Though you could parallel 2 each batteries and from them run to a 4 post bus.

 

[jmccrary]

Matt,
Thank you! Since fuses are cheap and a burned down house is expensive, plan on adding a lot for isolation lol. Also, the 6 stud bus bar is perfect, as much as equal length cables .

I really appreciate the help!

Justin