codename Bil Doe
07-04-2016, 09:50 AM
Mods, since there wasn't a general electrical section feel free to copy to other sub forums as it may be useful for everybody. I've seen a few suggestions buried in threads but nothing really stating how to fix easily.
I've been reading about people with batteries being drained completely and not knowing what to do. Don't immediately buy a new battery or tear the car apart to pull it out. There's a very simple fix.
Smart chargers need to see a voltage before they start charging. When your battery gets completely drained from sitting a smart charger won't detect it. I use battery tender jr trickle charger with that smart issue. Here's the solution:
Grab a 12v wall wart laying around that you don't need (any 12v transformer for an old cordless phone base or device will work). Make sure it's low current. <300mA is fine. It should be printed on the plastic.
Cut the plug off the end. Separate the two wires and strip about 2-3" off of each one.
CAREFULLY PLUG IT IN AND PROBE THE LEADS TO DETERMINE WHICH ONE IS POSITIVE. CAREFULLY! DO NOT CROSS THE WIRES WHILE PLUGGED IN!
Unplug the wall wart, and mark the positive wire with red tape. Wrap the positive wire around the positive terminal on the drained battery and the negative around the negative on the battery. Plug in the wall wart.
What have you just done? You've made a free (minus labor) "dumb" trickle charger. It doesn't have to see a voltage before turning on. It simply passes 12V at very low current into the battery.
Leave it on for 1/2hr to 1hr. This should get your battery back to 9-11V at which point you can switch it back to the smart charger.
I've been reading about people with batteries being drained completely and not knowing what to do. Don't immediately buy a new battery or tear the car apart to pull it out. There's a very simple fix.
Smart chargers need to see a voltage before they start charging. When your battery gets completely drained from sitting a smart charger won't detect it. I use battery tender jr trickle charger with that smart issue. Here's the solution:
Grab a 12v wall wart laying around that you don't need (any 12v transformer for an old cordless phone base or device will work). Make sure it's low current. <300mA is fine. It should be printed on the plastic.
Cut the plug off the end. Separate the two wires and strip about 2-3" off of each one.
CAREFULLY PLUG IT IN AND PROBE THE LEADS TO DETERMINE WHICH ONE IS POSITIVE. CAREFULLY! DO NOT CROSS THE WIRES WHILE PLUGGED IN!
Unplug the wall wart, and mark the positive wire with red tape. Wrap the positive wire around the positive terminal on the drained battery and the negative around the negative on the battery. Plug in the wall wart.
What have you just done? You've made a free (minus labor) "dumb" trickle charger. It doesn't have to see a voltage before turning on. It simply passes 12V at very low current into the battery.
Leave it on for 1/2hr to 1hr. This should get your battery back to 9-11V at which point you can switch it back to the smart charger.