Update : smoke left old manual charger

I bought this charger when in HS.
I forgot to unplug charger and the alligators shorted out.

I'm using diodes I salvage about 30 years ago. This is the last of my diode inventory.




Two problems. The cathodes make the metal frame of charger positive. Not good.
So I made a redneck insulator using a 2x2
And sheet of aluminum. .



Now the positive is no longer touching the metal frame.

Second problem. The diode's forward bias voltage is less the orginal diodes making the output voltage 15.5v.
Charging current to a fully charged battery is 15 amps.
Charger is rated at 12 amps.
I decided to add an inline fuse.
Currently using a 20 amp fuse.

Now I need to find a 120v dimmer to reduce the 120vac input voltage. I have a used dimmer some place.
Dimmer will work on this old manual charger.
I only use this charger when the battery voltage is so low a smart charger won't work.

When I use this old girl I use a timer so I don't forget to unplug it.

If I have another senior moment and forget to unplug the charger. Touching the alligators will blow the fuse.
Connecting charger with the wrong polarity will blow the fuse too.

Put a couple of diodes in series to drop some voltage

I have saved almost all of my bad chargers, in the hope of fixing them. Unfortunately, everything that you said was in a language that I don't understand. Although, I did manage to put a 3 wire alternator on my F 20 a few weeks ago and it charges. Alert the media. YAHOO

NEVER leave a trickle charger connected unattended. It will boil out the electrolyte in the battery and then the unit is junk. ALWAYS use a FLOAT CHARGER. A good one is the DELTRAN BATTERY TENDER, the JR Model is for 6V. $30 avg. Leave connected whenever tractor gets parked so it is at full charge under load when ready. Your trusty starter shop guy may be able to repair your fried unit...


Tim Daley(MI)

I know most diodes drop .6-.7v.
These diodes are different, less voltage drop.
I'm out of diodes too.
I may remove one wire from the transformer or use a dimmer switch.
Good news, the transformer works.
Someday I may buy new diodes.
4 diodes wired in a full wave bridge are cheap on Amazon.

The older ones are relatively simple. They usually have an ac transformer with multiple taps ( wires coming off the transformer at different voltages), these wires go to the charge selection switch. The AC is converted to DC in the rectifier (often some kind of plate that holds the diodes. The heavy DC cables are connected to the output side of the rectifier, hopefully the DC side has some kind of overload device (breaker). The rectifier is usually the problem. If the smoke has been let out of the actual transformer, the unit is scrap. I have found replacement rectifiers on-line, a direct replacement unit is not required. I replaced the rectifier in one of my solar's with an upgraded unit and it works much better. You can replace individual diodes in the rectifier also. Hint, when replacing diodes the wire in the actual rectifier is high temp wire and may be fragile. Replace any that are damaged with the wire used in a stovetop burner, use the high temp push on connectors also. The guys on this forum can assist you in the repair, show them the picture and they can fix anything.

The next time the smoke leaks out it might ignite you 2x2 heat sink mounting blocks! I repaired an old manual charger like that once, and had found a timer to install right in it, works well.