Join Date: Nov 2010
Thanked 309 Times in 280 Posts
Rep Power: 10
You have something buggered up. It should not make sense. Its wrong.
The contoller at night should read the battery voltage you read anywhere on your system. Not half a volt less.
If your battery is at 12.5 with no load and 12.3 with load your controller should say 12.5 and 12.3 respectively.