I've got a couple of old M12 and M18 batteries that have seen better days. The M12s are showing the annoying red/green charger error, and my M18s only charge up to three bars. Before I toss them in the recycling bin, I'd love to see if I can balance the cells and squeeze out some extra life. I've read that a variable power supply might be the way to go, but I haven't seen any solid recommendations for specific models. I'm aware of the risks involved and will take all necessary precautions. Any suggestions? Thanks!
4 Answers
I don't have M18 batteries, but I’ve worked with M12s. I modified an M12 charger by adding a balancing lead out front and cutting the traces on the PCB to isolate the original charger circuits. This setup lets me use a Turnigy RC battery charger to balance charge. For seriously dead batteries, I jump-start them with 12V from my bench supply just to get enough voltage for the Turnigy. You can do a similar thing with M18s! Instead of modifying an OEM charger, consider grabbing one of those cheap aftermarket chargers. I've got a lot of old M12 chargers lying around, which is why I didn't mind messing with one. A good balance charge every few months helps keep them healthy!
Just wanted to say I'm following this thread too—I’ve got two dead M12 6.0s and could really use some advice!
If you're just looking to balance your batteries, you might want to go for a Li-ion charger instead; it's usually cheaper and easier to use. Look into USB chargers like the TP4056 or the 18650 chargers such as the XTAR MC1 or MC2. They do charge slowly (about 1A), but you can find options that provide 2A or 3A if you want something quicker. Just use a dowel rod with alligator clips for connections.
If you plan on doing other electronics work, then investing in a variable power supply can be handy. There are plenty of affordable ones on Amazon or eBay, with Wanptek and Jesverty being common choices. Just be cautious if you go for much cheaper models—they might not be safe! For more in-depth info, check out some electronics threads; just keep in mind that they're often focused on other features related to powering small gadgets.
Using an RC lithium charger is a great option—it’s safer and charges faster. Just be careful with your batteries. I’ve dealt with lithium battery fires, and they can be incredibly dangerous! If one of these M18s goes up, it could cause a serious fire. Make sure you know exactly what you're doing before diving in.
Exactly! I've had a small lithium battery go into thermal runaway before. Even after dumping it in saltwater, it still burned for a while. An M18 can burn down your house really quickly, so always prioritize safety.