Battery Charger Q????????

[69a100]

I have an older 4 Amp charger, bought it back in 82. The gauge on it has broken but when plugged in in hums and when touching terminals, it sparks so I know it's working.
Hookin the charger up to a multi-meter, I only get 11.96 volts, shouldn't the voltage be higher, like 12.5 or more?
Just trying to figure out if the charger is dying or not?

 

[RemCharger]

Hook it up to a good battery, and put the meter on it. Now plug the charger in and watch if the voltage is going up.

 

[MoparLeo]

As important as the voltage is the amperage. 2-6 amps is good. excess amps can damage the battery.
Also best to charge battery out of the car.
Charging creates hydrogen gas which is explosive and hydrochloric acid fumes that can damage paint, local metals.

 

[Moms68]

I'd buy a new Battery Tender.

 

[kiwigtx]

I have an older 4 Amp charger, bought it back in 82. The gauge on it has broken but when plugged in in hums and when touching terminals, it sparks so I know it's working.
Hookin the charger up to a multi-meter, I only get 11.96 volts, shouldn't the voltage be higher, like 12.5 or more?
Just trying to figure out if the charger is dying or not?

The humming is caused by the laminations of the internal transformer breaking down - or at least the insulation of the laminations is breaking down.

That would also explain a loss of output voltage.

Best to look at buying a new battery tender as suggested by @Moms68 - they are not that expensive, and can be left on for extended periods of time - also without having to disconnect the battery from the vehicle.

 

[Richard Cranium]

Getting 41 years out of it is a good run.

 

[Detective D]

Amazon product ASIN B00CD44RQO
I use several of these as winter tenders and occasionally to charge a low battery(I have a gigantic box on wheels Shumacher from the farm days when I need more juice)
These will not only charge, they maintain without constant juice(that ruins a battery) and can do minor repair on the battery if the charge cycle is getting shorter. They come with clamps and if you would rather small eyelets to bolt onto terminals. The cord has a plug so you can set up the eyelets on the battery to use it as a maintainer and unplug when you want to drive so you don;t have to get any wrenches out.
Mine have gone through two WI winters in an unheated storage and the batteries are fresh in the spring.

Of course, when I got mine 2 years ago they were $45.

 

[WileERobby]

Just don't do this

 

[Hey-O]

When my car is off, this is on.
4 Amp Waterproof Battery Charger

 

[69a100]

Just don't do this View attachment 1463566

I may be a white boy, but I'm no dummy!