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herwig-maurer avatar image
herwig-maurer asked

what size fuse do I need between MPPT 150|35 Victron and my battery bank

what size fuse do I need between MPPT 150|35 Victron and my battery bank? (battery bank is 400aH 12V (2x 200aH)

fuses
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3 Answers
Alexandra avatar image
Alexandra answered ·

@herwig_maurer

Your mppt can put out a maximim of 35A so that would be the size to look at, as long as the cable you use also can take the charge current of 35A. Otherwise that will end up being the fuse if there is an issue.

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herwig-maurer avatar image herwig-maurer commented ·

thnx fro your answer! I have been using 35amp fuses between MPPT and battery bank, and they continuously keep popping. someone else advised me I can use a 100AMP fuse to avoid popping it non-stop... do u agree that is advisable? I want to ensure I don't damage my MPPT

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seb71 avatar image seb71 herwig-maurer commented ·

What wires are you using (gauge/cross section)?

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herwig-maurer avatar image herwig-maurer seb71 commented ·

10awg

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seb71 avatar image seb71 herwig-maurer commented ·

Then be happy that the fuses did their job.

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wkirby avatar image
wkirby answered ·

Fuses are not predictable especially when they are run right at their rated limit.
The fuse should be selected to protect your cable.
A fuse cannot protect an electronic device from being damaged, the damage is already done before the fuse steps in to prevent excessive current from causing a fire.

10AWG is pretty close to the limit for a circuit that regularly carries up to 35A, so the fuse is probably appropriate for that size of wire. Like seb71 said, the fuse has protected the wire.
It is no surprise that a 35A fuse melts unpredictably in a circuit that carries 35A for sustained periods of time. A larger capacity fuse should be selected. However 10AWG would be too small. 6AWG would be best in conjunction with a 50A fuse - for example.

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David avatar image
David answered ·

The correct answer is written on the left side of every 150/35 in white writing on that beautiful blue backround.

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