MPPT 100/15 battery current higher than solar current?

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Bryan Buttigieg asked May 27, '21

MPPT 100/15 battery current higher than solar current?

Trying to understand the reason why battery current on my MPPT 100/15 is consistently showing as being higher than solar current. My understanding with the 100/15 is that a positive battery current number means current going into the battery and a negative means current leaving. But how can current going in to the battery exceed what is coming off the panels?

100Wx2 panels. In series. A/C charger off. BMV 712 monitor and Blue Sea charging relay.

MPPT Controllers charger

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2 |3000

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Modifications Space

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Answer 1 · 2021-05-27T15:03:04Z

Matthias Lange - DE answered · May 27, 2021 at 03:03 PM

That's physic :-) P = U x I

37,79V x 0,5A = 18,89W

13,61V x 1,3A = 17,69W

(1,2W conversion loss)

higher voltage means less current for the same power.

lower voltage means higher current for the same power.

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greendovefarms commented · May 28, 2021 at 04:43 AM

Nice work !!!!

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gro greendovefarms commented · May 29, 2021 at 05:56 AM

MPPT solar charger has a a dc to dc converter. Therefore as shown above the current and voltage either side of the converter don’t have to be the same. But the product of current and voltage is power and that does have to be the same (minus efficiency losses)

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