Battery Trickle Solar Panels

[jimmied]

I have 2 3 1/2 inch x 11 1/2 inch battery trickle solar panels that I hooked up to my group 27 12 volt battery. Measuring the output from the panels, I get about 21 volts, but after a day in the sun, the battery does not even measure any input. Is this usual. I used to have 3 120 watt panels with 6 golf cart batteries and it ran everything with a 2500 watt inverter, so this small panel probably will not even keep the battery charged. Comments, please, Jim

[Thomas G.]

You can directly measure the input by putting the multimeter in series between the trickle charger and the battery.

How to use a Multimeter for beginners: Part 1 - Voltage measurement - YouTube

Also I heard anecdotally that some of the cheap solar chargers have no blocking diode, so they discharge the battery all night.
Diodes in Solar Panels Systems, Solar energy, solar panels, photovoltaic cells, batteries, inverters, power, electricity, energy

In battery charging systems, the module potential drops to zero at night, and the battery could discharge all night backwards through the module. This would not be harmful to the module, but would result in loss of precious energy from the battery bank. Diodes placed in the circuit between the module and the battery can block any nighttime leakage flow.

[Rene]

I have one of those trickle charge panels too. It is only a battery maintainer. In other words if your battery is fully charged already and you have no loads on the battery at all, it will keep the battery from loosing most of its charge over time when it is NOT being used. It will NOT charge a battery up after being discharged. PS: I think there is a diode in mine.

[jimmied]

Originally Posted by Rene

I have one of those trickle charge panels too. It is only a battery maintainer. In other words if your battery is fully charged already and you have no loads on the battery at all, it will keep the battery from loosing most of its charge over time when it is NOT being used. It will NOT charge a battery up after being discharged. PS: I think there is a diode in mine.

Thanks, Rene, for your reply. This is the answer I was looking for, so no use taking it camping with me while I am dry camping.

[Thomas G.]

For $30 you can get this 25 watt panel that will charge a battery, though slowly.

Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers

[jimmied]

Originally Posted by Thomas G.

For $30 you can get this 25 watt panel that will charge a battery, though slowly.

Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers

Thanks, Tom, for the link, but shipping to Canada will cost $38 extra, more than the cost of the panel. Us Canadians get the bum rap on having items shipped to us from the States, plus there will probably be taxes and custom duties on top...shucks....Jim

[Thomas G.]

Originally Posted by jimmied

Thanks, Tom, for the link, but shipping to Canada will cost $38 extra, more than the cost of the panel. Us Canadians get the bum rap on having items shipped to us from the States, plus there will probably be taxes and custom duties on top...shucks....Jim

Sorry - but maybe you can find similarly priced panels in Canada now that prices are falling so fast.

[Rene]

Yep, shipping makes or breaks the deal here in Canada! Ebay does have a few deals that are good for us here. Charge controllers are cheap to ship and there are canadian vendors on ebay that do offer some good deals on solar panels.