question

herwig-maurer avatar image
herwig-maurer asked

Why do my fuses keep popping

Hi there , hopefully someone can help me figure out what's wrong with my setup and why my 40amp fuses keep popping. It seems to be only the fuse on the positive cable that keeps popping.


My setup:
• MPPT 150|35 Victron smart solar charge controller
• BMV-712 victron smart battery monitor
• 2 x Renogy Deep Cycle Agm Battery IN PARALLEL - 2x200aH = 400aH @ 12V
• 2 x Renogy Solar Panel 160 Watt 12V ( if I connect only one, the problem still persists but seems to happen less frequently)
• 1500W erayak inverter ( fuses keep popping when this this turned off, so I don’t think this device plays into the problem)

According to my (novice) understanding the fuses should not be popping continuously.

I’m afraid to just disconnect the fuses, yet maybe I don’t even need them? Would it damage my MPPT if I disconnected them?
I appreciate any advice!

Thank you in advance!
Herwig
fuses
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2 Answers
herwig-maurer avatar image
herwig-maurer answered ·

PS: the fuses are between MPPT and the Battery bank

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michelg avatar image
michelg answered ·

Hi Herwig, As far as I remember, fuses should be 25% than the maximum load : 100A => 125A fuse, you inverter is pumping up to 125A to provide 1500W !! so I'll recommend you installing a 150A MEGA fuse.

I use a 3kVA inverter at 24VDC, and my fuses are rated at 125A, never had an issue. Before I was using smaller ones, and they did blown up.

Give it a try.

Michel

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herwig-maurer avatar image herwig-maurer commented ·

thnx for your advice! I was going by the 35amp MPPT... doesn't that have to be protected with a 35amp fuse?

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duswami avatar image duswami commented ·
I'm having a similar issue. I also have a 3000w multiplus ii (120v) connected to a 48v system through the lynx distributor. When I close the circuit (turn ON the DC from the bats via the disconnect) my 125A fuse blows on the batteries. There's no load and the inverter is off when I attempt to power the bus bar (Lynx Dist.) Can't figure out the issue. Any ideas. Polarity is correct.
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