question

Michael Connolly avatar image
Michael Connolly asked

Multiplus charging jumping to 16v regularly but I can’t find the problem

fdc6213f-1e38-448f-92b4-ca9c01a2b2a7.jpegImage CaptionMultiplus

680lifepo a/h at 12v nominal

3x MPPt smartsolar

Charge voltage spiking on mains charging.

The lower spike is because the solar kicked in…no issue.

The other spike is the problem…has happened multiple times.

Any ideas???

Mick

3908cc53-3a1d-447b-a168-97b4f13eba54.jpeg
battery charging
fdc6213f-1e38-448f-92b4-ca9c01a2b2a7.jpeg (255.7 KiB)
3908cc53-3a1d-447b-a168-97b4f13eba54.jpeg (4.2 MiB)
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.

6 Answers
Paul B avatar image
Paul B answered ·

this is a guess but you may find the the batteries bms is disconnecting the batteries as its occuring when the batteries are being discharged so one cell in the bank might be flate.


anyway look at the bms at the same time it happens

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.

Michael Connolly avatar image
Michael Connolly answered ·

I have, there is no events in the BMSs (3) that correspond with the events except shutting down the batteries for over voltage.

Thank you for your answer.

Michael

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.

Trevor Bird avatar image
Trevor Bird answered ·

@Michael Connolly as an aid to fault finding I would reduce the absorption voltage on all charging sources by at least a volt to see if that can try to eliminate any BMS activity. I have seen BMS activity cause abrupt voltage changes (interpreted by a Quattro as DC ripple) causing all sorts of problems. You have to do something and reducing the charging voltages may help lead you to the cause of the problem.

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.

Michael Connolly avatar image
Michael Connolly answered ·

d1fa4c49-03c4-40c0-a02e-a161e68c742d.pngA zoom in on the 16v event.


d1fa4c49-03c4-40c0-a02e-a161e68c742d.png (356.4 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.

Trevor Bird avatar image
Trevor Bird answered ·

Yep, that is very strange alright. I have no idea why that is happening. It is over a long term so not battery BMS related I don't think.

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.

Michael Connolly avatar image
Michael Connolly answered ·

I have dropped the absorbsion as suggested

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.

ejrossouw avatar image ejrossouw commented ·

I would use a fixed charge curve for LifePO4 and no battery safe given there is no gassing risk.

0 Likes 0 ·