wiring up a pack in parallel and series

[readyhouse@gmail.com]

I am setting up a battery pack using 3.7 volt prismatic cells - I am putting 25 sets (in series) of 3 batteries together in parallel to make a 92 volt pack - My question is can I use 25 mm (3 gage) to wire up each parallel set and then use 50 mm (0 gage) I will attache a simple schematic to show what I mean - further to this question I cant get my head around how in a pack using little 18650 batteries are connected together with tiny little wires even though 850 volts and mega amps go through the pack ? how do they work out the setup -View attachment wires.pdf

 

[amberwolf]

I am setting up a battery pack using 3.7 volt prismatic cells - I am putting 25 sets (in series) of 3 batteries together in parallel to make a 92 volt pack - My question is can I use 25 mm (3 gage) to wire up each parallel set and then use 50 mm (0 gage) I will attache a simple schematic to show what I mean - further to this question I cant get my head around how in a pack using little 18650 batteries are connected together with tiny little wires even though 850 volts and mega amps go through the pack ? how do they work out the setup -wires.pdf

Your post is a bit confusing, so a few questions first.

Are you using prismatic (box shaped) cells, or are you using 18650 cells?

Assuming you're using 18650 cells, then:

Where are you getting 850 volts from a 25s pack of 3.7v (average) cells? It would only be a maximum of 105v if fully charged to 4.2v.

Also, how do you get mega amps (which is millions of amps) from a 3p pack using 18650 cells? With good cells that can handle say, 10A each, you would only get 30A from that. 90A if you pulled 30A from them (whcih would heat them up significantly). If they're average cells you would probably only get 3-6A or so from each, so 9-18A. (depends on the specific cells).



Regarding the interconnect wires, we'd need to know the currents you expect to draw from the pack to help size those.

 

[john61ct]

Please link to the cells

You also might want to ask a mod to change your handle, or wow you'll be getting a lot of unwanted emails, even with gmail's good spam filtering.