Where can I get a dumb battery charger?

Messages
228
Location
TN
I don't have any experience with this charger, but it seems to be a "manual" charger. It is from Harbor Freight, so there's that. Battery Charger
 
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Messages
1,767
Location
Toronto Canada
I take it you already have a modern "smart" battery charger and some old battery it won't recognize. Find one of those old little black power supplies [wall wart] for a cordless phone or some other device, you may be able to start charging a dead battery with one of those. One that puts out between 10 - 18 volts D.C. is ideal. Adapt the wires to the battery clamps of your smart charger and let it charge for a day or so. This should bring the battery to a state where the smart charger can take over.
 
Messages
1,627
Location
Cincinnati, USA
It is very easy to build your own, merely needing a 12V transformer and rectifier diode. For example you could use a transformer from a landscape lighting set if it's the old linear style instead of the newer with a switchmode PSU, or if you are not in a hurry, one of those old school wall wart AC/DC adapters that just has the transformer, diodes and a capacitor inside. You can tell them apart because they are typically larger and heavier, closer to a square/cube shape, and that without a load their output voltage is closer to 16V. For that matter if you are creative with resistor values you could even use a switchmode 12V AC/DC adapter. You'd put the resistor in series so the current stays low enough that it doesn't go into shutdown from being under voltage. That would only bring the battery up to approx 12.0V but that should be enough, and yet it is usually going to be the slowest way to charge, taking closer to a week depending on discharge state and battery capacity.
 
Messages
24,604
Location
Upstate NY
Aren't there other solutions like attaching a jump pack for an hour to bring up the voltage of the dead battery to a point where the smart charger will accept and charge the battery?
 
Messages
2,700
Location
USA
Looks like they still make the Schumacher SE-5212A. You want the A one with an analog meter on the front not the E one with LEDs. I have an old SE-3005 which is very similar and it will revive (or attempt to) batteries that are run down to zero.
 
Messages
1,077
Location
Wisconsin
Rummage sale? My fathers 60's era Schumacher 2/6 6v/12v Charger still works great, I use it weekly on my old truck that seems to have a slow short. I've also built a deadman's charger for battery recovery of failed batteries using about $5 of parts and some broken junk I have laying around http://www.alpharubicon.com/elect/3dollarbattggn.htm It's similar to this but I made mine out of a power strip an extension cord and a shop light (so I can control the amps)
 
Messages
14,124
Location
Central NY
I have one from harbor freight but can't find it. So to get my "smart" charger to work I hooked up a good battery to a dead battery with jumper cables and then started the charging.
 
Messages
2,213
Location
Lyndhurst NJ
You can trick the smart ones by using another battery with booster cables, usually you can slam it for about 15 mins and then remove the good battery from the loop. If theres no readout checking with a voltmeter would be a good idea to get an idea of where the battery is at after a while. I can do this with my Snap on D tac charger, if it sees a decent battery it can throw 80 amps at it, and most times when he good battery is removed youll see a pretty steep drop off in the amp output. However, it has brought back many batteries that have worked for me long term.
 
Messages
6,642
Location
South Florida
Most of these smart chargers have a way to bypass this "safety" to get them to start pumping out voltage, if you read the manual. If not, I hooked the used battery up to a good battery via jumper cables, and then you can start pumping voltage into it.
 
Messages
4,432
Location
Connecticut
Originally Posted by mk378
Looks like they still make the Schumacher SE-5212A. You want the A one with an analog meter on the front not the E one with LEDs. I have an old SE-3005 which is very similar and it will revive (or attempt to) batteries that are run down to zero.
I use a similar Schumacher marine battery charger. I think it only cost around $25-$40 new. Had it for 15-20 yrs, not really sure. It has brought back several nearly dead batteries. I think in one case I charged continuously for 8 hours. Got 3 more years out of that one. Just clip it on and go. The only glitch with mine is that if you exceed the full scale amp charging rate (10+ amps) it will kick you out on over load. In those cases changing the ground can lessen the charge rate to get you going.
 
Messages
271
Location
Northeast Georgia
Another Schumacher smart charger user here. Mine is a "Ship N' Shore" unit with regular/deep cycle/AGM options and voltage levels of 2/10/15. It also has a desulfation mode that will pulse charge a DEAD battery back to the point of being able to accept a normal charge. I've had this thing for 10 years and it still works great. I've revived several "completely dead" lead acid automotive and ATV batteries with it.
 
Messages
921
Location
D/FW Metroplex
I feel like the OP lacks the requisite knowledge to apply the information given in your post, lord knows I do. But then again, if we understood what you were talking about here, we wouldn't need to post up the question in the first place, right? I really hate Catch-22s...
Originally Posted by Dave9
It is very easy to build your own, merely needing a 12V transformer and rectifier diode. For example you could use a transformer from a landscape lighting set if it's the old linear style instead of the newer with a switchmode PSU, or if you are not in a hurry, one of those old school wall wart AC/DC adapters that just has the transformer, diodes and a capacitor inside. You can tell them apart because they are typically larger and heavier, closer to a square/cube shape, and that without a load their output voltage is closer to 16V. For that matter if you are creative with resistor values you could even use a switchmode 12V AC/DC adapter. You'd put the resistor in series so the current stays low enough that it doesn't go into shutdown from being under voltage. That would only bring the battery up to approx 12.0V but that should be enough, and yet it is usually going to be the slowest way to charge, taking closer to a week depending on discharge state and battery capacity.
 
Messages
1,077
Location
Wisconsin
Originally Posted by The_Nuke
I feel like the OP lacks the requisite knowledge to apply the information given in your post, lord knows I do. But then again, if we understood what you were talking about here, we wouldn't need to post up the question in the first place, right? I really hate Catch-22s...
Could you build this Deadman charger? Also Dave is just referring to a dc walwort bought for 50 cents from saint vinneys. If it puts out a tad more than 12 volts you just cut the end off and attach the positive wire to the positive battery post and the negative wire to the other one. Not very complex and if you have old broken electronic toys you may already have the wallwort

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Messages
40
Location
AZ
That's because they're designed to be turned on by the very battery you're trying to charge, meaning the battery has to be at over 6V - 8V. It's a safety feature, to prevent sparks if the AC is plugged in before the clamps are attached. Some people have modified the circuitry by tracing it out and finding another 6V - 8V voltage source inside the charger. When I ran my battery down to 1.5V, I hooked up a desktop PC power supply's +12V output to the battery, with a 100W, 8 ohm resistor in series to limit the current to about 1.5A, then when the battery voltage got high enough I used my regular charger. You should be able to use a laptop AC adapter the same way, if it can put out at least 3 amps, but the resistor will get hotter because most laptop AC adapters put out 19.5V, meaning the resistor can dissipate up to 50 watts, and you always want the resistor to be rated for at least double the actual watts.
 
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