Series and parallel multi meter

[Jah-de-blah-0m]

Beginner question I wired 10 Battle Born 12 volt batteries into 24 volt series and parallel connections. When testing with my multimeter I noticed that only the terminals were the parallel connections are made are reading 26.6 whereas other terminals in the system are reading 13.3 why would this be more of a curiosity.

 

[740GLE]

Depends on how you’re measuring, any time you’re reading across just one battery “cell” it’ll be nominal voltage.

you have to read across two series batteries to read full voltage of the bank.

 

[RCinFLA]

Two 13.3 volt batteries in series equals 26.6 volts.

Running five strings in parallel is going to have some variance in the amount of load current taken up by each string. Better then 15-20% current distribution variance is good.

Each battery has its own independently operating BMS so be watchful of strings cutting out. I would definitely not center strap all the middles together and leave them as five independent 24v strings in parallel.

Each Battle Born 12v battery has 120 cells (26650 size 65mm long by 26mm diameter) arranged as thirty 3.4 AH cells in parallel by four series connected 30 cell groups with an internal BMS.

 

[Jah-de-blah-0m]

Two 13.3 volt batteries in series equals 26.6 volts.

Running five strings in parallel is going to have some variance in the amount of load current taken up by each string. Better then 15-20% current distribution variance is good.

Each battery has its own independently operating BMS so be watchful of strings cutting out. I would definitely not center strap all the middles together and leave them as five independent 24v strings in parallel.

Each Battle Born 12v battery has 120 cells (26650 size 65mm long by 26mm diameter) arranged as thirty 3.4 AH cells in parallel by four series connected 30 cell groups with an internal BMS.

Thanks for the info... wish I understood exactly what you mean... in particular center strap. As I am pretty sure that's what I did... But I couldn't see any other way to do it....

 

[Jah-de-blah-0m]

Depends on how you’re measuring, any time you’re reading across just one battery “cell” it’ll be nominal voltage.

you have to read across two series batteries to read full voltage of the bank.

Thanks this makes sense I just went out and tested them and understand what you're saying thank you so much for taking the time to answer my question

 

[RCinFLA]

From top picture looks like connected corrrectly.

Each Battle Born has its own BMS. You should get a clip on amp meter to check how each string is supplying current. Ideally each series branch should be 1/5 of total output load current but this is not likely. Again, within 15-20% mismatch is reasonable.

Remember any one of the battery's BMS could disconnect due to low cell, high cell, overcurrent, or temp. You will lose contribution from the string with open BMS cutout switch. This will likely be due to imbalance of internal cells. It is more difficult for this 2s5p arrangement for each battery to do its self equalizing balancing. You may have to occasionally disconnect and charge an individual battery to accomplish better rebalancing on its internal cells.