10W panel on a 200ah battery bank

[kje]

On my summer-cottage I left my 10W panel on a 200ah battery bank standing until next summer. I know it's too small current for this battery bank, but will it destroy the battery bank?

The alternative was leave the battery bank without the panel connected. It's an old battery bank I got for free. My big panel was priority on my agm battery.

[Mike90250]

well, if it has an internal blocking diode and was made for charging a car battery, it would help. If no diode, it should have a controller or a diode to prevent nighttime backfeed

[Sunking]

Without a controller or diode, the battery will be destroyed. The reason is simple, the panel appears as a load when there is no sunlight discharging the battery. What little charge the panel can generat ein a day does not compare to what it discharges at night.

[kje]

It has a diode and a charge regulator attached. ☺
The 10W panel gives 0.65A at the most.

I just wonder if too small current can harm the big battery bank?

[Sunking]

It is only enough to keep the battery charged assuming it was fully charged to start with.

Not sure I follow you when you say you have a diode and controller. I hope that is not the case. The controller is all that is needed. A diode just cut another watt or two off the power on top of the controller losses.

[kje]

I thought you meant the diode between the panel and battery so the panel don't drain the battery when shadow/dark. ☺

I just have a straight forward solar regulator. The battery bank was fully charged to start with.

So it doesn't harm the battery bank with too small current from the panel? (0.65A at most)