I needed a manual charger today

[y_p_w]

I couldn't get any of the "automatic" chargers to work with my car that's sat for a while in the driveway. I have a Schumacher SC-1200A (12A/3A), which I think is discontinued, but it works great other than there's no 12V/6V switch. It just assumes that if the voltage of the battery is under maybe 7V that it's a 6V battery and then applies a suitable voltage. I still have a traditional 1.5A Schumacher automatic maintainer with a 6V/12V switch, but even with the 12V switch it would just indicate that it was "charged".

So the only thing that worked was whipping out the old 1A Schumacher wall wart charger. After a couple of hours the battery was showing about 11.5V and the automatic charger can take over and charge the battery.

If my 1A wall wart ever failed, I'm not sure where to find a new manual charger. I've never really used it other than to revive a battery that more sophisticated chargers give up on.

 

[brianl703]

When I need to charge a completely dead battery, I start with a 300W variable power supply with adjustable voltage and current limiting. Set it to about 14V at maybe 5A. When the battery is pulling close to 5A, then I finish the charge with a regular automatic charger.

 

[Vercingetorix]

Noco Genius chargers have a force mode for completely dead batteries.

 

[JeffKeryk]

Noco Genius chargers have a force mode for completely dead batteries.

I just read that today. Coulda used it too...

 

[Torrid]

Noco Genius chargers have a force mode for completely dead batteries.

I don't have a Noco charger but I have one of their jump boxes that has this feature. I wondered if their chargers would have this.

 

[spackard]

California’s gotten rid of the old transformer manual chargers. The cheapest hack is to parallel the dead battery with a good one, then charge both.

 

[SubieRubyRoo]

I couldn't get any of the "automatic" chargers to work with my car that's sat for a while in the driveway. I have a Schumacher SC-1200A (12A/3A), which I think is discontinued, but it works great other than there's no 12V/6V switch. It just assumes that if the voltage of the battery is under maybe 7V that it's a 6V battery and then applies a suitable voltage. I still have a traditional 1.5A Schumacher automatic maintainer with a 6V/12V switch, but even with the 12V switch it would just indicate that it was "charged".

So the only thing that worked was whipping out the old 1A Schumacher wall wart charger. After a couple of hours the battery was showing about 11.5V and the automatic charger can take over and charge the battery.

If my 1A wall wart ever failed, I'm not sure where to find a new manual charger. I've never really used it other than to revive a battery that more sophisticated chargers give up on.

Most (all?) of the NOCO jump packs that can literally fit in a pocket have an emergency mode bypass for cases like this. It removes the safeguards for excessively low voltage, reverse polarity, and maybe some other things too. So, if you hook it up wrong to the battery, you could cause an explosion.

I’ve used the NOCO to jump the car and run it long enough to get the voltage up if my Clore Automotive charger won’t start a charge cycle. It’s very convenient!

 

[zzyzzx]

California’s gotten rid of the old transformer manual chargers. The cheapest hack is to parallel the dead battery with a good one, then charge both.

That's exactly what I did. I drove the riding lawn mower out to a truck parked on the lawn and used jumper cables to fool a smart charger into working.

 

[Hermann]

I couldn't get any of the "automatic" chargers to work with my car that's sat for a while in the driveway. I have a Schumacher SC-1200A (12A/3A), which I think is discontinued, but it works great other than there's no 12V/6V switch. It just assumes that if the voltage of the battery is under maybe 7V that it's a 6V battery and then applies a suitable voltage. I still have a traditional 1.5A Schumacher automatic maintainer with a 6V/12V switch, but even with the 12V switch it would just indicate that it was "charged".

So the only thing that worked was whipping out the old 1A Schumacher wall wart charger. After a couple of hours the battery was showing about 11.5V and the automatic charger can take over and charge the battery.

If my 1A wall wart ever failed, I'm not sure where to find a new manual charger. I've never really used it other than to revive a battery that more sophisticated chargers give up on.

My old non auto Schumacher 6/2 will have to be pried out of my hands when i die. Great old charger.

 

[930.engineering]

It just assumes that if the voltage of the battery is under maybe 7V that it's a 6V battery and then applies a suitable voltage.

At just under 7V this battery's dead anyway.
.

 

[zzyzzx]

At just under 7V this battery's dead anyway.
.

Actually no. I've had the lead-acid battery drain much lower on the seldom used truck in question multiple times, and charged it back up several times and had it work fine for years. Having written that, it's connected to a 1.5W solar maintainer which is probable the only reason it still works.

 

[y_p_w]

Actually no. I've had the lead-acid battery drain much lower on the seldom used truck in question multiple times, and charged it back up several times and had it work fine for years. Having written that, it's connected to a 1.5W solar maintainer which is probable the only reason it still works.

My wife's car sat on the driveway for a few months with a bad transmission. Had to charge it several times and it was definitely under 7V. But the battery (a Deka Group 51) is still going strong after more than 5 years.

 

[930.engineering]

Actually no.

Actually yes. And you're not the OP. A 12V battery 'under 7V' is dead or at least near to dead, not a reliable item.
.

 

[SHOZ]

I have an old 6/2 charger. probably 40 years old. Replaced the cords a couple of times.

It will chare a completely dead battery , agms too, but takes a couple days. 12hr sometimes before it starts showing any charge.

You can get a adjustable DC power supply of 1-3 amps or so.

 

[andyd]

My old Sears 2/10/75 charger will often not start charging at 2 amps if the battery is really flat. It will charge at 10amps for a while then I can charge at 2A. overnight which will usually result in a good cold start.