DC Circuit Breaker Between MPPT and Battery Keeps Tripping

DIY
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1

Hello everyone, I need help with something that is not directly related to Victron; however, it is an important component for my Victron system to function properly.

My equipment is as follows:

  • 1 Multiplus-II 5000VA 48V
  • 4 panels of 550W 24V (connected 2 in series: 96V)
  • Victron MPPT 12/24/48V 60A
  • Dyness A48100 battery

Between the MPPT and the battery, I have an 80A 550V DC circuit breaker. For the past two days, this breaker has been tripping, and the battery stops charging. I don’t understand why this is happening, as there were no issues before. However, on the same day the problem started, I made some adjustments to better organize the system (I arranged the cables). I have already checked for any loose terminals, but everything seems correct.

In the last day, the VRM shows that the battery was charging at 1770W, and the loads were at 141W.

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What could be causing this? I have always had doubts about this breaker—are the values correct?

This is the MPPT config

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I’ll appreciate any help

2

What is the brand and model number of the DC breaker?

3

Brand: Suntree
Model: SCB8-125DC

I’ve found this PDF with information:

DC-circuit-breaker-80100125a

4

I would not use a circuit breaker in this position, but a suitably rated dc fuse - 63V, 80 - 100A.
This will give a greater time delay on the fuse blowing. The breaker is probably tripping prematurely due to thermal effects. Unfortunately after a few times tripping, some models of breaker just keep tripping at lower and lower currents.

2 Likes
5

Yes thats better, the suntree is also a very cheap chinese breaker, cheap ones always have problems

6

Thank for you answers guys, what would be better, remove the circuit breaker or buy a better one? or maybe use other type of protection?

7

Use a fuse as suggested

1 Like