Beginners Question

Hey Guys,

Sorry for pestering you with such an easy question, but I am a little los when it comes to "bus bar sizing"

Lets imaging i want to use a 24v Battery and a 24v inverter to draw 3600 Watt of power at 220V.

When dividing 3600 Watts by 24V I end at 150 Amps.

Do I understand correctly that at the Plus and Minus Pole of a 7s 19p Battery the bus bars have to be around 16x 1.6mm of Pure copper?

( I used this table as a reference:
https://www.australwright.com.au/technical-data/advice/copper-busbar-rating/


Does since Current requirement is just necessary for the Plus / minus pole were all the power is siphoned from, or do the busbars that connect the parallel cell also have to have this dimensions?

I am just a little unsure wither my general approach here is correct!

Also I have another stupid question...

Lets say I have a 12 V Solararrays and put them into a 12V MPPT solar-charger, could this (albight slower) charge my 24v Battery?

Thank you very much für th time !

Best,
SackofFluor

25mm2 seems pretty light on for 150amp draw, I think that chart allowed for a 50deg temp rise in the bus bar (was blurry and couldn't read it on my Ph) . A quick Google puts rule of thumb bus bar thickness for copper mm2= A/1.2
So 125mm2 for continuous draw at 150amps. Ie ~12x10mm copper (which seems about right).
This is presumably for minimal temp rise and/or long runs.

However most applications don't require Max draw all the time soo.. you might be able to halve that thickness and get away with it if you are only drawing Max amps for short periods of time. Depends on your application and ambient temps, air flow etc
For reference, 8g awg is aprox equal to 10mm2 and it gets noticeably warm at 30amps cont, thats with silicon insulation but in free air. I wouldn't wrap that up in say a battery or have it insulated for whatever reason.

As for charging a 24v battery off a 12v solar panel. Probably not is the short answer. Unless you step up the voltage with a dc-dc converter.
A 12v panel puts out ~18v open circuit which is well below what a 24v battery (of unknown chemistry) needs to charge (~29v)
2x 12v PV panels in series would do it (through your charge controller).

kdog said:

25mm2 seems pretty light on for 150amp draw, I think that cha

Click to expand...

No it is not. It is fine. That is alot of copper.

Its like a 4gage wire.. Lol. 150A? no prob. Last bike I built with a 4gage wire did over 280A peak @ 72v... ( 18kW) and 160A contin without ever getting hot ( on the FLIR cameras)....

My 8 gage bike does 100A.. ( 8,000w) and 60A contin.. ( 4200w) and does not get hot much ( 5* rise, maybe, reported by the FLIRs) ... But I also dont use the silivcone junk wire. I use real 1000v SLX wire or the like. Good wire.. .


25mm^2 is fine for 150A. For sure.