I have a SmartSolar 100/20 MPPT and being away in the van, I got curious about the performance. I noticed that when the battery is completely isolated and the van is in storage, there is still bulk charger every day for between 1 and 2hrs. This surprised me somewhat as there should be no drain as everything is turned off.
Do you think that either I have a unknown drain or is my battery dying and not able to hold charger?
HI @mattb1969
Have you got a electrical tester with CT clamp on it. Quick way to see if any current is being drawn from battery when you think everything is off.
"battery is completely isolated" means that no pole of it is connected.
Your battery is obviously at least connected to a charger, therefore it is not "isolated".
"Thinking" is guessing. You need to measure or log the current that is flowing out of the battery.
If that is not the case depending on your secret battery type a built-in balancer might trigger recharging.
Your MPPT remains connected overnight, this has a small current drain to keep the system alive but it should be small. If you have lead acid batteries they will have some self discharge overnight. Your solar is small and at sunrise will not be producing much power so it will always go into bulk for a period until the power has increased from the panels. The key is once the panels are running, the absorption period is 1 minute. In other words the battery is not discharged, it has taken 2 hours from the solar panel receiving the first few meagre rays to start generating anything meaningful. It is better to look at how many Wh or Ah have been charged or the chargong current during bulk compared to your battery capacity to see if it is losing much capacity overnight.
If you ask questions then it is worth providing all info such as battery type and capacity.
