Should MultiPlus temp compensate in Absorption mode?

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bonsys asked Sep 21, '23

Should MultiPlus temp compensate in Absorption mode?

MultiPlus-II (firmware version v506) with the charge profile configured in AGM mode with -18mV temp compensation does not increase absorption voltage to compensate for the battery temperature at 14 degrees. Why?

14.7V + (-0.18V x (14C - 25C)) = 14.7V + (-0.18V x (-11C)) = 14.7V + 1.98V = 16.68V

I am not observing expected 16.7V at all. Instead the MultiPlus-II is hovering around predefined 14.7V without temp compensating.

In which mode temp compensation should be applied: bulk, absorption, float?

Multiplus-II AGM Battery temperature compensation

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Answer 1 · 2023-09-21T18:37:33Z

pwfarnell answered · Sep 21, 2023 at 06:37 PM

Your maths is wrong, the effect is much smaller than you have calculated.

14.7V + (-0.018V x (14C - 25C)) = 14.7V + (-0.018V x (-11C)) = 14.7V + 0.198V = 14.898V == 14.9V.

18mV is 0.018V. You calculated using 180mV.

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