Do SmartSolar charging algorithms self adjust for cable runs or should I pick a higher charging algorithm?

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gavinge asked May 26, '20

Do SmartSolar charging algorithms self adjust for cable runs or should I pick a higher charging algorithm?

340W panel. into 100/30 Smart solar. charging AGM 110ah batteries. THese batteries want an absorbtion voltage of 14.6-14.8volts.

I have a 10-12foot cable run. I currently have installed AWG10 wire between the smart solar and the battery which means if I set the charge profile to profile 3 and 14.7 volts, the voltage at the batteries I think will actually be 14.26v. this isnt enough for these batteries to absorb correctly.

Here is where my electrical knowledge has a gap.

should I select a higher charging profile like profile 5 with 15.1v at the charger and a resulting 14.66 at the batteries after the voltage drop on the cable or will the voltage selected in the profile be the voltage at the batteries?

i.e. do I need to adjust the profile to account for voltage drops in the cable?

smart solar set-up help

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Answer 1 · 2020-05-26T02:49:44Z

Guy Stewart (Victron Community Manager) answered · May 26, 2020 at 02:49 AM

Hi @gavinge,

Cable runs and voltage drop/rise can have an effect on charging performance, especially over long distances, high currents, and small wires.

One of the issues with a 'manual' adjustment of the voltage set points is that voltage drop/rise is also includes a factor of the current, so a higher current will increase the apparent rise.

A much more precise way to do it is have 2nd set of readings that are taken by different non-current-carrying wires, as close the battery as possible.

This is further improved by the addition of precise temperature compensation, which also changes the target charge voltages

Using that 2nd battery voltage reading, combined with the temperature reading gives the best charging accuracy/performance.

There are several ways to do this in a Victron system. If you only have the SmartSolar, then the addition of a Smart Battery Sense, will provide both of these.

If you already have a Victron MultiPlus and GX device, then the include sense information from the Multi can be shared with the MPPT using DVCC.

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