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brent1982 avatar image
brent1982 asked

Suitable Circuit breakers

Hello,

Im just after some advice on a suitable circuit breaker between the panels and the mppt

I will be installing 3 (potentially a 4th in the future) Victron poly 175w panels in series and a Smartsolar 100/50 MPPT but am unsure of which circuit breaker to install between the 2 in order to isolate the panels if need be and also for safety.

Given voltage will be up around the 72 mark what would you suggest? With 4 panels it will be around 94v


Between the MPPT and batteries would it be advisible to install a 60 or 70amp medium duty thermal circuit breaker?

MPPT ControllersMPPT SmartSolarsolarwiring
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2 Answers
wkirby avatar image
wkirby answered ·

Thank you for editing you question, the panel connection makes sense now.
Four panels in series is very close to the maximum Voltage of the MPPT. If you encounter a cold sunny day, the PV array Voltage may exceed 100V and then damage the controller.

For circuit breakers, select good DC rated circuit breakers. AC ones not rated for DC with set themselves on fire.

The circuit breakers listed below are some of my favourite reliable DC ones.

MNEDC15 - 15A for the PV - MPPT circuit.
MNEDC60 - 60A for the MPPT - Battery circuit


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brent1982 avatar image brent1982 commented ·

Thanks for the reply. I've used the victron spreadsheet to calculate the panels in use, and even at zero degrees where I am (which in unlikely to encounter) they will still fall below 100v. There will only be 3 panels installed to begin with an a 4th if I feel the need for it further down the track.

So I only need a breaker on the input rated to the Max amps of the panel? That makes it easier to understand.


Cheers

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ejrossouw avatar image
ejrossouw answered ·
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