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Busbar size
#1
What busbar size would you recommend for a 14s80p system with a maximum current draw of 110A for 30 min and a max. continuous draw of 85A. Running a busbar loop across the standard 4x5 cell holders, ideally each side obviously sees half the max. current.
And would you recommend going with twisted pair of 2.5mm2 (or similar) or one a single bigger conductor?
Best,
MPM
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#2
Located in the FAQ section, there's this: What size of wire / fuse wire should I use?
It has several graphs of wires and amp ratings
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#3
Thank you. So running three twisted strands of AWG10 /2.5mm wire in a loop be plenty?!
Best,
MPM
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#4
More than enough. For my 40p packs I use 3 strands of 14 AWG but I don't see that many Amps. I have 3 Sets currently of the 40 P packs and The most any Pack sees is about 50A
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#5
That would be fine. 10AWG can do about 40A, x3 would be 120A, which is slightly higher than your required load. Altho, this is pretty close to max current of the wiring bundle. You could possible add a strand of 14AWG as well and that'd put you well over the limit. Maybe make the 14 the core, the 3 10's around it.

The limit on 3 10AWG wires is about 120A. You want/need 110A, with a little math we come to 92% load capacity. This could cause heating up of the wires. Increase heating is an increase in resistance, which causes an increase in heating. So the longer the high current is used, the heat will start to increase almost exponentially. By adding the 4th wire, this reduces the load to a mere 81% of the limit of the wire-bundle.
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#6
Im using 6x2.5mm2 for 80A. I count 16A per 2.5mm2 as generic current here Smile
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#7
(08-08-2019, 01:12 PM)Korishan Wrote: That would be fine. 10AWG can do about 40A, x3 would be 120A, which is slightly higher than your required load.  Altho, this is pretty close to max current of the wiring bundle. You could possible add a strand of 14AWG as well and that'd put you well over the limit. Maybe make the 14 the core, the 3 10's around it.

The limit on 3 10AWG wires is about 120A. You want/need 110A, with a little math we come to 92% load capacity. This could cause heating up of the wires. Increase heating is an increase in resistance, which causes an increase in heating. So the longer the high current is used, the heat will start to increase almost exponentially. By adding the 4th wire, this reduces the load to a mere 81% of the limit of the wire-bundle.
 I will think about that. However, correct me if I am wrong here, but if run in a loop each side of the busbar would be connected to 40 cells and the three strands of AWG 10 of the loop would meet on one side forming a 6 stranded connection to the next pack. Hence, if both busbar sides are somewhat balanced, they would only see a max of 55-60A each and only the 6 stranded connection point sees the full 110A. 
I don't know if my thinking is wrong here and am looking forward to your reply. 

Best, 
MPM
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#8
You are correct and thats how most of us do it. 3 strands in a loop
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