Solar power setups for the garage
- Thread starter RazorsEdge
- Start date
Actually the lifespan is a function of the depth of discharge. Unlike deep cycle lead acid batteries a LiFePO4 battery can be safely discharged 100% and still offer 2-3000 cycles. Reducing that to 80% discharge and you might get 6000 cycles. That's a potential of more than ten years. I did experience a failure of one of these batteries in under a year but it wasn't the battery per se. A temerature sensor failed high making the battery management system think that it was to hot to charge or discharge. Luckily the entire battery was replaced under warranty.
Thank you for the inspiration. This is exactly what I’ve been considering for my shed, and the exact same use case to power battery chargers.
Do you mean battery chargers or battery tenders? My inspiration came 19 years ago in France when I saw a 10 watt panel tending the battery on a lawn tractor without benefit of any storeage or a charge controller. This was 12 volt (nominal) panel to 12 volt battery. It gets more complicated quickly once you cross the Rubicon to battery charging, lighting or running power tools.
I will be recharging Dewalt batteries for my cordless string-trimmer and mower. The mower is used for spots my zero-turn can’t quite get to, so not even deep discharges.
I’m thinking your setup might be a bit overkill but I’m still learning about this stuff. I need to put eyes on my chargers to see how much current they draw.
But now that you mention it, a battery tender for the off-season would be good for my zero-turn…
My rules of thumb for a conservative solar design the overnight drain would be max 20-25% of battery capacity and the panels should have enough output to recharge 50% or more on a sunny day. This will get through 2 or 3 cloudy days in a row with no interruption.
In a garage interruptions may not be a big concern but you still want plenty of battery to reduce the typical depth of discharge.
Come to find out, being at the end of the line is where the spike goes! FPL came out and repaired the neutral, installed a new transformer and magic circuit breaker on the transformer instead of the constantly blowing fuse. Beyond that the suggestions were to install a meter box surge protector (done) and a CB box surge protector (done). No help what so ever.
Back on topic, a modest solar panel (50W) can (SOMETIMES) charge a 100AH LiFePO4 battery with BMS directly, without a charge controller. As the current is low, the BMS will shut off the charge when voltage climbs over 14.8V (about). While it's not really the ideal solution and the BMS must be robust enough to do this every day, it can be a way to have a simple system.
One can even purchase a BMS and cells and make your own. Just keep the panel size well below the max charge current. Size it carefully.
Sure it's less efficient. But so what? It will likely provide good service if quality parts are chosen.
Or just get this kit and a battery:
https://www.amazon.com/Renogy-Monocrystalline-Negative-Controller-Connectors/dp/B00BFCNFRM?th=1
Last edited:
