Another solar question
Submitted: Saturday, Mar 03, 2012 at 13:40
ThreadID:
92261
Views:
1801
Replies:
4
FollowUps:
0
This Thread has been Archived
nootsa200873
Hi all, back again looking for some more solar info. I have connected my new system, to the batteries on my camper via a sunsaver 20 regulator. Now my question is regarding what my multimeter should read. I admit that the batteries are fully charged at the moment. When I connect the solar system, The multimeter reads....
Solar panel at the reg - 12.52 volts
Battery side at the reg - 12.52 volts.
Do the above readings sound right?
Cheers,
Chris
Reply By: Member - John and Val - Saturday, Mar 03, 2012 at 17:56
Saturday, Mar 03, 2012 at 17:56
"Do the above readings sound right?" No. Suggest
check your wiring carefully. It sounds as if solar input and battery connections are tied together. Or maybe the solar panels are not in fact connected and the battery voltage is leaking through to the solar input terminals? (
Check the panel voltage on the back of the panel if poss)
With the panels in the sun and disconnected from the controller you should see about 21 to 23 volts on the panels - that's their open circuit voltage.
Battery voltage is very dependent on history over the last few hours, and also on battery chemistry. If disconnected from everything for a couple of hours you should see 12.5 - 12.7 volts on a wet cell battery, usually a little more on AGM.
While charging, you should see at least 13.4V and maybe up to 14.8 (even higher for calcium batteries) measured at the battery. I assume that you are using the Morningstar MPPT controller. This should hold the panel voltage at about 17 to 18V while charging and the battery voltage at around 14.4V until approaching fully charged when it should drop back to about 13.4.
Complicated?... yes!! These numbers too will vary a bit with battery chemistry.
A further consideration - these controllers use pulse technology, resulting in rapidly changing voltages that average out at the right level. Digital meters take a virtually instantaneous reading, rather than an averaged one, so you can get some pretty erratic measurements, and may need to do a bit of mental averaging to get a useful reading.
HTH
John | J and V
"Not everything that can be counted counts, and not everything that counts can be counted."
- Albert Einstein
Lifetime Member My Profile My Blog Send Message |
AnswerID:
479302