question

reefman avatar image
reefman asked

Multiple SmartSolar MPPT, Smart Battery Sense, different cable lengths

Hi - I'd like to setup a couple of SmartSolars 75/15 in my caravan, one for the roof panels and one for an external 'portable' solar panel. Given the way my caravan is wired, I will have to place the one of the Solar Controllers about 5 meters (cable length) from the batteries, whereas the other would be right next to the batteries.

Sounds like the cable lengths for the MPPTs should be matched if possible (unless I misunderstood something). Will a Smart Battery Sense help with the mismatch? What is the consequence of have quite different cable lengths?

Thanks

Bruno

MPPT Controllers
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2 Answers
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wkirby answered ·

When charging, the MPPT with the longer cables will be measuring a higher Voltage at its battery terminals than what the battery Voltage actually is. This could cause it to switch float before the other MPPT with shorter cables.

You could set the two Smart MPPT's ina network for synchronised charging. A Smart Battery Sense would help also.

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reefman answered ·

Great - many thanks for your reply. I will install a Smart Battery Sense and network the MPPT's.

Compared to same length cables, will this (networking/smart sense) result in an, say 80% solution, or is it a minor improvement to a poor installation?

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