Hi,
I have 4 security lights which are solar powered with an 18650 rechargeable battery in them. I use them to light my driveway up at night on motion detect. They work great in the summer but not so much in winter.

Is there a way I can remove the 18650 batteries and run them all from a much larger capacity battery. Could this also be charged from solar?

Not sure if I'm in the right place to ask this by hopefully someone can point me in the right direction.

Many thanks

 

Welcome to AAC!

Without knowing more about the lights, it's difficult to make suggestions.

What is the capacity of the current 18650's? Is there a way for you to connect a larger solar array? Is routing power to them an option? You mention running them all from a larger battery. Are they close enough together to do that?

 

If you want to keep the setup solar powered, then it appears that, at the least, you need to get more energy from your panel. The solution might be as simple as angling the solar panel on them to better catch the winter sun, since it appears there's margin available in the summer. If that's not enough, then you will need to add additional panel area somehow. If the existing battery, if fully charged, is sufficient to get through the winter night, then you don't need a bigger battery (though that might help get through short periods of several days with insufficient sunlight).

Just adding an additional panel might be easier said than done, since the new panel needs to be compatible with the existing panel. But it would probably not be too difficult to disconnect the existing panel and replace it with a larger one.
They also make solar power modules that come complete with a panel and a battery, so you could integrate one of them and bypass the existing panel and battery. Probably a bit more expense, but something that would probably be pretty simple to do.

 

I've experienced the same thing with my solar lights. Though my solar lights are garden lights and not security lights. I'm currently in the process of removing the solar feature and just planning on powering them from a 12VAC source and use automotive LED marker lights in them and hard wire them to a photo sensor to determine when to turn them on. I already have been using the same hookup for the lamps mounted into the fence posts but not inside old solar garden lamps.

Using a larger battery would require using a larger PVP (Photo Voltaic Panel) and hard wiring them all together. But there again you have the problem of low angle solar energy reaching the PVP. You may have to shoot for way over kill just to get the same lumens you get in the summer time.

Then there's the type of battery you choose. Depending on what battery you choose you have to match the proper charging profile. Get that wrong and you could have a fiery problem. Li-Ion batteries can be dangerous when not handled properly. I happen to have a double rack of time bombs on my shelf. As long as they don't over charge or over discharge they should be safe enough. But let either condition occur and I could be owner of a 2700 square foot charcoal briquette.

After sounding the warning I just checked the condition of my 18650's. The lowest resting voltage observed was 3.39V and the highest resting voltage observed was 4.15V. I believe (could be wrong) the proper storage voltage for these batteries is 3.8V or close to that.

 

For your 12 volt AC supply with the solar sensor, "Malibu" makes a nice weather resistant ten amp box that includes to solar timer. I was asked "to take a look at it" when a friend reworked some garden lighting. The bad part is the power terminals used non-plated steel screws.

 

Totally get the struggle with winter sun! Yeah, you can definitely swap out those 18650 batteries for a bigger capacity battery. Just make sure it’s the right voltage and can handle the load. You can also hook it up to a larger solar panel setup to keep it charged, no problem. Just gotta make sure everything’s compatible and set up right. And here are some things to remember: https://www.energy.gov/energysaver/outdoor-solar-lighting
And, while you're at it, consider going big with a larger solar power setup. You might be able to cash in on some sweet tax incentives! Check out this guide for more info, https://california.statesolar.org/

 

For your 12 volt AC supply with the solar sensor, "Malibu" makes a nice weather resistant ten amp box that includes to solar timer. I was asked "to take a look at it" when a friend reworked some garden lighting. The bad part is the power terminals used non-plated steel screws.

Thanks Bill but this isn't my thread. AND my 12VAC transformer body is sealed and has a photo cell. I don't know what else is in there but at dusk it turns on. But let's not take this thread away from the TS.