Temperature Busbar DC side

Q&A and troubleshooting
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1

Hello ,

last week I have exchanged 2 pieces of thick battery cable ( 95 mm2 ) with copper bar 4mm thick and 25mm in width

between the 2 cables I got an DC switch rated for 350 Amps. I got put a temperature sensor ( the one provided with a Multiplus ) on the Multiplus end of the DC switch the sensor is plugged in my Cerbo GX

1 cable end from the DC switch is connected to a Victron 250A busbar where the positive battery outputs of 3 Multiplus-II inverters ar connected with on each lead a fuse

the other end of the DC switch is connected to a second Victron 250A busbar where 2 cables ( 50mm2 thick ) are going to my Battery with fuses in-between each cable going to a 16kWh battery

the reason I made the change was because the temperature when discharging around 200Amps was exceeding 130 degrees celsius !

now I am using copper bar 5mm thick and 25mm width instead of the pieces 95mm2 cable on either side of the DC switch

now the Temperature doesn’t exceed 110 degrees celsius

Can somebody tell me if this is normal ?

2

I would say this is too high. The copper itself, with this cross section area, will not heat up that much, I would guess that the connection points are the problem here and the copper is just the better heatspreader. Do you have access to a thermal imaging camera? But be aware, that pure/blank metal is difficult to scan with that kind of camera…