Newbie Help

[NewbieSolar123]

We love outdoor low voltage lighting. We have been using these unique individual solar power devices you get on Amazon but problem is most are junk and never charge the AA it uses to light up for more than 1 hour. So I decided to venture out. Did some research and bought a Renogy 50 watt 12 volt solar panel. Picked up the 10 amp Renogy controller with solar, battery and load controls. Picked up a 12 volt sealed AGM 9AH battery. And since these light don’t run on 12, they run on 2.6 volts, picked up a voltage regulator that takes the 12 volts and lets me down it to 2.5 volts. Now all is running. Lights are on. I can see they pull total about .20 amps which is very small and I run from dusk to dawn. So 10 hour roughly.

Problem I had, I didn’t realize the controller had an option to turn on the load when solar stops charging and turn off the load when it starts to charge. So I put a photocell switch on the load terminal before my voltage regulator that feeds the lights. And I left my controller on constant on. So during the day there was a small .2 amp draw from the photocell switch and then the added .2 amps at night. Second problem was controller was set to lithium charging and not sealer battery. Over night my battery which I thought is over sized went from 4 bass to 1 bar and it didn’t charge back up fully during the day. I have since removed the photocell and changed the controller to built in load controller based on charging and also changed the charging to sealed battery. Do you think this system is large enough to run that .2 amp draw for 10 hours and be able to charge back? Could it be that the battery didn’t charge due to wrong type?

Finally do you have any recommendations? I plan on adding a few more 2.7 volts lights. Maybe a total of 1 ah use. Should I change to a lithium of larger battery? I was hoping the 50 watt would be able to charge and maintain this small load.

Sorry for the long description but wanted to give the full background.

Thanks.

 

[Reed Cole]

If panel gets sunlight for most of the day you should be good with that setup.

It could very well be that the lithium charge profile is inadequate for agm. So that's a good place to start troubleshooting. Also, I would try to monitor the charge controller during the day to see how much power you are actually producing. If it seems normal and your battery still isn't charging then investigate the health of the battery, which could be compromised at this point if it's been chronically undercharged.

You don't need a lithium battery but they do have the advantage of not needing to be fully charged on a regular basis, unlike lead acid chemistries. If your AGM ends up working fine after the changes just keep using it until it doesn't.

 

[NewbieSolar123]

Thank you. So it seems to be ok. I am having trouble with the direction of the sun fully charging the batter back during winter. Too much blockage. Trying to find a optimal spot. I did upgrade to a Victron SmartSolar 75/10 Controller. I heard and read that MPPT charger would be better. Not much costlier plus I like the solar tracking in the bluetooth enabled app.

I did have one further question. How can I get how fully charged my battery is? Is there some device I can connect that can tell me if my battery is 50% charged or 25% charged? That would be nice to add on.

 

[krby]

I did have one further question. How can I get how fully charged my battery is? Is there some device I can connect that can tell me if my battery is 50% charged or 25% charged? That would be nice to add on.

There are a few different ways. The easiest for you would be something like the Victron battery monitors. Look for Smart Shunt or BMV-702. The former has no display, you connect to it from your phone via Bluetooth (so limited range). There are cheaper shunt-type monitors, but the Victron ones are popular.

Or you can go with just a voltage monitor like this one: https://www.amazon.com/dp/B0C3R2H2S5
This will not be as accurate, but AGM batteries should get you in the neighborhood of "100% vs 70% vs 40%" full. When the battery is being charged, it is useless, though.