# question

## Setting temp the compensation value on my mppt bluesolar.-

Based on Victron "mppt-solarchargers" white paper: "The configured coefficient is in mV per degree Celsius for the whole battery bank, not per cell".

If my battery bank is wired at 48Vdc (Lead Acid) by one string of 8 batteries, 6 volt each (3 cells), -0.005mV per 2V cell/ºC (per manufacturer) would it be -0.12mV/ºC the right value to set here?

If this compensation occurs automatically, why the system allows you to choose between a positive or negative value?

thx!

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Johannes Boonstra (Victron Energy Staff) answered ·

Yes, then -0,12mV would be the value.

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Martijn Coster (Victron Energy Staff) answered ·

Hi DCPablo,

The value you should use: 8*3*-0.005=-0.12mV for the whole bank.

We made the system flexible that is why there is the option positive and negative temp compensation. We are working on making this simpler.

best regards

Martijn Coster - Victron Energy

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Thanks Johannes & Martijn!

Good to heard the "minus" value is correct here as a "loss coeficient" make sense. But if you put it by mistake as a positive maybe the controller could does the maths reverse decrising the voltage when is cold and rising it when is hot... a little bit dangerous.

I´ll be attentive regarding new news on this issue.

Greetings,

Pablo

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