MPPT 100V/15A - Safe setup to set and forget?

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offgridclays asked Mar 29, '21

MPPT 100V/15A - Safe setup to set and forget?

Hi all!

I recently bought a Victron MPPT controller and I installed it yesterday at a remote location that gets attened once a month.

I have fed it with two 300W panels in series giving me 80V@10A (Overkill I know but those are the panels available to me)

I have installed 10A circuit breakers on both the Positive and Negative before the PV feeds into the Controller. Cable for the PV is 4mm2

I have the Controller charging two identical lead acid truck batteries in series - their capacity would be 300 to 400AH combined. Setting is at 24V. Cable for the charge cable is 10mm2

Using bluetooth I set the charging algorithim to the "Default 2" setting at the advice of an off the grid electrician.

Can you guys give me advice as to how safe this setup is? I am primarily worried about the Charging Algorithim as the descriptions didn't seem to fit exactly with my battery hardware.

Thank you!

battery charging offgrid lead-acid

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Answer 1 · 2021-03-29T08:34:14Z

seb71 answered · Mar 29, 2021 at 08:34 AM

You should have a fuse on the positive wire between the battery and the solar charger. This fuse should be close to the battery, if possible.

Also, if you have a load connected to the battery, another fuse there.

You said nothing about wires cross section/gauge.

Are those two batteries identical? It's not clear.

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offgridclays commented · Mar 29, 2021 at 09:08 AM

The two batteries are identical.

The wires from the PV panels are 4mm2 and the wires charging the batteries are 10mm2

No load on the battery (yet) but I havent fised the charging cable either

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