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overland avatar image
overland asked

tripping a fuse after solar Changer

I recently installed four 300W solar panels on my RV. I'm using a Victron smart Solar charge controller MPPT 100 / 50 that is protected by two 60amp fuses on both sides of the positive line. The 60 Amp fuse that is exiting the Solar Charger and going to the Victron Multiplus 12/3000 keeps tripping. I was pulling in around 650 watts from the solar panels. The 4 solar panels are wired in Parallel. the wiring on the Solar Charge and fuses is 6AWG. I don't think I was bringing in any ware near 60amps so I don't know why the fuse was tripping. Is my fuse not big enough? Thanks much!

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4 Answers
seb71 avatar image
seb71 answered ·

If it trips, it's not a fuse. A fuse blows and then you have to replace it.


At 650W and with your 12V (nominal) battery, that means the current from the solar charger to the battery was close to the maximum 50A.

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overland avatar image
overland answered ·

sorry, a 60 amp circuit breaker is tripping. the four Solar panels are 300 watt, 24 volt.


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wkirby avatar image wkirby ♦♦ commented ·

A 60 Amp circuit breaker should be rated to carry 60 Amps all day long, emphasis on the word should.
High ambient temperatures can cause the thermal component of a circuit breaker to activate at a lower current after a while. Check the datasheet for your circuit breaker.
Also, some poor quality circuit breakers don't carry their rated load for very long and then give up at a lower current.
A good 60A breaker with in reasonable ambient temperatures (probably rated at 25°C) should carry the 50A that your charge controller makes at full power.

Another important point to bear in mind. The circuit breakers are not there to protect your charge controller, they are there to protect your wiring. Fuses and circuit breakers cannot foresee a fault inside a piece of equipment and they are very to slow to respond.
You should always rate your circuit breakers for the size of cable that you are using.

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overland avatar image
overland answered ·

it's this circuit breaker https://www.amazon.com/gp/product/B077D1C7L3/ref=ox_sc_act_title_1?smid=A28LQLUGKI63QO&th=1

Shouldn't a 60 am circuit breaker be ok for 6AWG wire? Should I replace it with a bigger circuit breaker?

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klim8skeptic avatar image klim8skeptic ♦ commented ·

Choosing the cheapest rubbish circuit breaker is not a wi$e investment.

$pend a few dollars more.

NB. in the 2 years my system has been up, I have blown a cheapy cb. Different type, but budget..


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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

I'm not a fan of circuit breakers in DC lines. I prefer to use fuses.

The fuse is protecting the wire and the wire size must be selected correctly for the length and current you need.
A correctly sized fuse will never blew under normal conditions.

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michelg avatar image
michelg answered ·

Hi, I had such kind of issues by not using the recommended cable. I mean, it was 35mm2, but not "welding type", which is the cable having the most smallest wires making it 35mm2.

I changed the breaker, rebuilded all my cabling with the recommended one, and no more issues. It was difficult to find it, and I used battery cable, which was not adapted.

Victron and wiring recommendations

You should get a better idea on how to do the things.

Michel

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