question

jc-alacoque avatar image
jc-alacoque asked

MPPT 250/100

12 X 100W panels in series/parallel on roof of motorhome. 12V batt bank. Inside the shop with ceiling lights on, the PV open voltage is showing 75V. But when I connect it to the controller, it drops to 12.5V. The batteries are at 12.6V. Should it not be able to charge the batts ? Thanks.

battery charging
1 comment
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.

Alexandra avatar image Alexandra ♦ commented ·

@JC Alacoque

Check your polarity?

Do you have a smart product?

0 Likes 0 ·
2 Answers
jc-alacoque avatar image
jc-alacoque answered ·

Polarity is right. Smart product? The controller is a Victron MPPT 250/100, if that is what you mean. Just panels to controller to batteries.

1 comment
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.

nickdb avatar image nickdb ♦♦ commented ·
The mppts came in different flavours. On the mppt it will say SMART or not, as part of the branding.
0 Likes 0 ·
Alan avatar image
Alan answered ·

Your shop lights will trigger some voltage, but not enough energy to drive output from the panels.

If you took a 100W bulb, and 20% of it's total output landed on the panels, which are 20% efficient, that's 100W x 0.2 x 0.2 = 4W. That's not entirely accurate, but you see where it's heading.

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.

Related Resources

Additional resources still need to be added for this topic