TV Battery Charging With Solar?

[jeff4506]

First time towing in the dark last night for several hours... running with batteries in "store" mode. I have the factory-installed solar charging but when I finally stopped my batteries were at 70% (maybe around 12.4 volts). I verified (prior to trip) 12V feed from TV. Was wondering if TV should still charge batteries even with these conditions. Age of batteries explain the 70%, but normally show 100% in the daylight due to solar charging. I assume if the TV charge was getting to the batteries it would have been 100%. Any thoughts?

[bryanl]

If using voltage (or specific gravity) to measure state of charge, you need to have had no significant charging or discharging for an hour or more on the battery.

Your tow vehicle should have a charge line that parallels the engine battery and the trailer battery when the engine is running. Due to the wiring and other things, the charge rate is not that high but it should still bring the state of charge on the trailer battery up, especially over a 4 to 6 hour daily run.

Setting batteries to 'store' mode might be running them disconnected from everything - if that is the case, they won't receive any charge.

When you measure voltage with the solar controller connected or with the tow vehicle connected and running, you are measuring the charge voltage, not the battery voltage. You can use that measure to see if the battery is receiving a charge from those sources.