SmartSolar MPPT 100/50 - fuse blowing between controller and battery

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sailaway3662 asked Dec 22, '19

SmartSolar MPPT 100/50 - fuse blowing between controller and battery

I have four 12V 140 watt solar panels wired in parallel that have worked for 5+ years on my former Blue Sky controller. I want to switch over to Victron so bought the SmartSolar MPPT 10/50 and move the four wires (two PV and two Battery) from the Blue Sky to the Victron. Everything came up and my VictronConnect app showed the panels charging. After 10 minutes my 50 amp fuse between the Victron the batteries blew. A replacement fuse blew instantly. Perplexed because I did not change any wiring - just moved them over from the old controller to new. I've rechecked my wiring and did not accidentally reverse any.

solar fuses

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Answer 1 · 2019-12-23T01:23:05Z

Rob Fijn answered · Dec 23, 2019 at 01:23 AM

Hello Sailaway, What will happen if you connect only the battery to the MPPT ?

This connects to the left hand side.

The Fuse you replaced, this you did during a very sunny moment ?

best regards,

Rob

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Answer 2 · 2019-12-23T02:54:04Z

JohnC answered · Dec 23, 2019 at 02:54 AM

Hi S. Try a bigger fuse, maybe 70A? Given that fuses are largely to protect the wiring, maybe also replace the wires with larger ones. Your 100/50's terminals spec 13mm2 wire, and I'd go at least that, even 'tapering' bigger wire to fit. You may also find a need to step up to a different style of fuse/holder to accommodate this upgrade.

General reference: https://www.victronenergy.com/blog/2019/09/03/wiring-unlimited/

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