Hi, new to the forum.
My problem is the battery (AGM) in my caravan is not charging properly.
This is my set:
200w solar on roof, Victron SmartSolar 100-20 MPPT charger, 120Ah AGM Battery.
When I measure the voltage at the output of the charger it reads say 14.1V then read it at the battery terminals it reads 0.5V less.
My question is: is the 0.5v drop my problem and is preventing the battery charging properly. Would it be Ok to increase the voltage from the charger to compensate for the drop?
If I do increase the voltage using the app should I increase it on Bulk, Absorption and Float?
Hi,
one possible reason of this voltage drop is the wire section. The cable is too thin ?
Here a figure with the max possible current (A) by cable section and distance for a 3% voltage drop for a 12V system. (The total distance is the length of the 2 wires, the (+) and (-))
It will help you to understand if the cable is OK, or not really according to power level of you system.
After that you can imagine to increase the voltage value with MPPT settings to reach the battery specification.
Xabi.
You could fit a smart battery sense to compensate for the cable losses
An inexpensive and handy device 
To check:
- Cable section
- Bad connections/contacts
- Switching device (if exists) high resistance
First check these before increasing voltage.
Increasing voltage combined with one or more of the above could increase the possibility of a fire, because any of the above will increase the heat dissipation…