chatelot16 wrote:there is only the panel which produces energy ... if the panel is too small there is no solution!
Yes.
But there, we have the impression that the battery does not charge at all (mas I did not understand if it was a test without consumers
)
chatelot16 wrote:cable section: it is only the cable between regulator and battery which is important: if this cable is too long the regulator slows down the charge before the battery is full
too long, or too thin (or with bad connections leading to voltage drops).
chatelot16 wrote:the cable between panel and regulator is much less important: the panel can do a few more volts without significant drop in current
In total, the power produced can still be affected, but that should not prevent charging the battery.
It seems to me that it would be necessary to carry out a test without any consumer, over several days if necessary, to find out if the battery is recharging (I have the impression that not ...).
After 2 or 3 days without consumption, it should exceed 13V (while it turns more between 11,5 and 12 currently, which is rather a sign of an almost empty battery).
And it is absolutely necessary to make intensity measurements (panel, regulator, battery, consumer) and not just voltage.