I have a shed in the far back of my yard that currently has no power. I managed to hook up some LED light bars using an old car battery and a wall switch, and it works great! Now, I'm looking to add a small solar panel to keep the battery charged. I'm a bit confused about whether I need a solar trickle charger, which I assume has float functionality to prevent overcharging, or if I should invest in a proper PWM or MPPT controller. Given that I rarely use the lights and usually only for a couple of minutes, what do I really need? When does a trickle charger become insufficient, and I would need a controller instead?
4 Answers
I faced a similar situation. I mounted a used 180W panel on the roof of my shed, connected to an Amazon PWM charge controller to keep my lead-acid battery charged. It powers a few lights and an IP camera without any issues. Just keep in mind that while those small trickle charger panels are okay, they may not fully refill your battery if you're using it for more than just light. Better to go with something more reliable!
The small trickle chargers work well for maintaining battery health against self-discharge, especially if you don't have heavy parasitic draws. However, with just LED lights and minimal usage, you might find them adequate for your needs. Just know that with a low wattage like 7.5W, don’t expect a full charge quickly—could take weeks to recharge a depleted battery!
It's all about balancing your energy use and how you recharge. Good trickle chargers can put around 20Wh into the battery on a sunny day, which is enough to run a 5W LED for about 4 hours. However, a larger setup like a 100W panel with a PWM controller could give you around 400Wh daily. Just remember, a bigger solar panel often means better results!
I'd recommend a 100W panel with a PWM charger for solid performance; even a 50W panel could work just fine since your lights are minimal. I use a 100W panel with a Victron MPPT and it powers my lights and other devices efficiently, despite some shade. Just make sure your charger has a compatible float voltage for your battery!
Thanks for the insight! I was looking at those tiny all-in-one panels with built-in trickle chargers. Do they really work for preventing battery discharge overnight?