Like new battery
So I have a cordless lithium-ion drill that I keep up at the shop. I use it quite a bit, but over the winter months, not so much. So one of the batteries has sat on the charger ready to use for a month or so. I was working on a project last week and needed to swap batteries only to find the one sitting on the charger was dead. I tried taking it off and putting it back on several times only to have the charger flash once and the light go out, meaning it wasn't going to charge the battery.
Well I got to doing a search for replacement batteries, which were coming out to about $70 each. Now I wouldn't have done that as I can buy a whole new impact driver with a charger and two of the same batteries I use in my drill for about $105 (which I plan to buy anyway at some point ). However I saw an article about how many of the lithium-ion batteries have a safe-guard circuit built in that will not allow a battery to re-charge if it reads 0 volts. Typically, from my understanding, this is because the battery could have allowed copper to settle causing a bridge which may short between the plates causing harm to the charger, etc. The article said that one could use a car battery charger and do a quick boost charge to bring the battery above the 0 volt level, which will get the charger to start charging the battery again.
Well, with some long wires connected to the batter and taking some safety precautions, I gave it a try. A word of caution, try this at your own risk and don't overload the battery on your car charger, it only takes a few seconds. There are plenty of youtube videos showing the repercussions of overcharging a battery . I was charging 18 volt batteries with a 12 volt charger, one would not want to charge a smaller battery than the charger was designed for. Anyway, sure enough after about 5 seconds on the 12v/6 amp setting on my car charger it held enough of a charge to get the drill charger to charge it again. I've been using it in the shop all day long. Lesson learned, swap out your batteries on the charger often, they don't re-charge themselves automatically, at least mine doesn't.
To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault