Brandon avatar image
Brandon asked

What fuse type is best for Multi-plus II?

Hi there,

Which fuse type is best for fusing the Multi-plus II? ANL, MEGA fuse, CNN fuse, other?

I imagine a slow blow fuse would be better so that it withstands short spikes of current from the inverter for short periods. I'm thinking of going with the MEGA fuse as it seems they are slow blow where as the other aren't (or they vary)? Just wanting to get some advice as to weather this would be the best option?

Also wondering which fuse type would be best for fusing each battery? I will be running 2x UP2500 25.6V Pylontech batteries.

Multiplus-IIPylontechBattery Protectfuses
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1 Answer
wkirby avatar image
wkirby answered ·

The 32V MEGA fuse would be just fine for the inverter circuit. I also use those.

No need to fuse each of the Pylontech batteries, they have their protections built in. Just link them together as described in the manual.

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Brandon avatar image Brandon commented ·

Than you. This may seem like a dumb question but if I have a Smart solar MPPT 150/100 TR. Should the fuse in the DC output positive cable be 100A?

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Warwick Bruce Chapman avatar image Warwick Bruce Chapman Brandon commented ·

Yes, fuse the link between MPPT and battery.

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wkirby avatar image wkirby ♦♦ Brandon commented ·

100A fuse might be a bit low for your setup. I vaguely remember that your system could reach 100A battery current at times, so a 100A might only last a few hours at 100% capacity.
For example, from the datasheet, a 100A MEGA fuse may open after 4 hours at 100% capacity.
Maybe a 125A fuse would be better here as long as your cabling is rated accordingly.

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rslifkin avatar image rslifkin Brandon commented ·

I agree with wkirby. As long as the wiring can handle a bit more, go up 1 size above 100A. My 30A MPPTs have 50A breakers on the battery side, for example (and the wiring is fine for 50A). I would have gone for 40A breakers, but the wiring could handle 50 and I already had those on hand.

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