question

Bryan Buttigieg avatar image
Bryan Buttigieg asked

MPPT 100/15 battery current higher than solar current?

c357813c-2710-4fd1-8368-4d9399fc8e8f.pngTrying 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.
764aea5a-91d5-4a97-9be7-969dacf29bf6.png

MPPT Controllerscharger
764aea5a-91d5-4a97-9be7-969dacf29bf6.png (309.5 KiB)
c357813c-2710-4fd1-8368-4d9399fc8e8f.png (342.2 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

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.

2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

greendovefarms avatar image greendovefarms commented ·

Nice work !!!!

0 Likes 0 ·
gro avatar image gro greendovefarms commented ·

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)

0 Likes 0 ·

Related Resources

MPPT Product Page

MPPT Error codes

MPPT 150/60 up to 250/70 Manual

Chargers.

Additional resources still need to be added for this topic