Older Schauer 10A Auto Cut Off Battery Charger

[Propflux01]

Got ahold of one of these, a model CCR12, in very nice condition. Its been a long time since I've used this type, but I seem to remember hooking these up, the ammeter would go to 10A and stay there, and as the battery charged, it would slowly move towards 0A, and then be considered 'charged', and the unit would automatically shut off. I carried this out to my Zero turn which has not had a trickle charger on it all season. Hook this up, turn it on, and the meter goes full right, then back to "0', and repeats at intervals of about a second or two. You can hear the charger buzz more indicating current usage, when the meter goes fully right. Sort of acting like a buck converter, but goes very slow intervals. The battery had a charge to it, the engine turned over normally, and I don't have any other dead batteries to test on. For all you old schoolers that used these, is this normal to charge like this, or should it be a bit smoother?

 

[ctechbob]

That sounds like there's a short and it is kicking in the protection circuit.

Does it do it with the leads connected to nothing?

 

[Propflux01]

That sounds like there's a short and it is kicking in the protection circuit.

Does it do it with the leads connected to nothing?

No, does nothing when leads are disconnected. I can make the little circuit breaker trip if I connect the leads together. Takes about 10 seconds.

 

[ctechbob]

No, does nothing when leads are disconnected.

That's odd. Shouldn't be overloaded with just a single small battery.

Just as an experiment, disconnect the battery from the machine (Pull the + or - lead to the machine) and connect the charger and try again.

I can't imagine it making a difference, since if there were a short in the machine, you'd know it, but I can't come up with anything else at the moment other than a faulty overcurrent protection device in the charger.

 

[JHZR2]

10A may take the voltage on a tiny yard battery up to 14.x V prety darn fast. And it probably has high enough impedance to not take a lot of current when its there. So I suspect the circuit is protecting because its oversize and overly conservative.

Try it on a car battery and see what happens...

 

[JimPghPA]

I don't know the actual schematic of the circuits used in that old charger. That said, many old chargers had a simple transformer and full wave diode setup ( either bridge or the center tap transformer with two diodes ) as the supplier of power, and then maybe some additional circuits to protect, and or time, and or select charge rate.

Back in the day, like 1960's the common United States residents house power was 110 Volts AC RMS and 220 Volts AC RMS for high power applications.

Over the years, the standard residential house power Voltage has been steadily increases, so now as high as 127 Volts AC RMS and 254 Volts AC RMS can commonly be seen.

This creates a problem with old chargers, because most that simply have a transformer and diodes as the heart of the supply will have the secondary voltage of that transformer put out an increased voltage proportionately to the increase of line voltage they get plugged into. And many old chargers will put out too much voltage because of this and damage batteries.

That may be part of what is going on with your old charger.

 

[Cujet]

Even so, the old school chargers will often put power in a battery when the digital ones wont. They are absolutely worth keeping.

That seems kind of normal for that kind of charger on a small battery.

 

[hemitom]

Even so, the old school chargers will often put power in a battery when the digital ones wont. They are absolutely worth keeping.

That seems kind of normal for that kind of charger on a small battery.

This right here !
I have a charger like this but older it's a 2amp 10 amp 55 amp boost . when plugged in the needle will go to ten amps then settle in at a lower rate depending on the state of charge .
I would try the charger on a car ! maybe leave the headlights on for fifteen minutes then put the charger on and see how it acts on a discharged battery.
Funny enough story around a month ago kids next door Tucson would not start. so I go over with my lithium booster pack which was left in the back of my car showed full charge but wouldn't even crank it over it is about 8 years old and now when left in the cold really has no power.
So I break out the old charger hook it up put the switch to ten amps and the charger is putting out ten amps of charge according the gauge leave it on ten amps for about five minutes to help warm up the battery throw the switch to 55 amp boost wait about one minute tell him to give it a try and bang fires right off.
So if you do have one of these old chargers they are worth hanging on to.

 

[Propflux01]

Even so, the old school chargers will often put power in a battery when the digital ones wont. They are absolutely worth keeping.

That seems kind of normal for that kind of charger on a small battery.

This is the reason I bought it. My older one was voltage dependent, until it died for good.

 

[Propflux01]

I don't know the actual schematic of the circuits used in that old charger. That said, many old chargers had a simple transformer and full wave diode setup ( either bridge or the center tap transformer with two diodes ) as the supplier of power, and then maybe some additional circuits to protect, and or time, and or select charge rate.

Back in the day, like 1960's the common United States residents house power was 110 Volts AC RMS and 220 Volts AC RMS for high power applications.

Over the years, the standard residential house power Voltage has been steadily increases, so now as high as 127 Volts AC RMS and 254 Volts AC RMS can commonly be seen.

This creates a problem with old chargers, because most that simply have a transformer and diodes as the heart of the supply will have the secondary voltage of that transformer put out an increased voltage proportionately to the increase of line voltage they get plugged into. And many old chargers will put out too much voltage because of this and damage batteries.

That may be part of what is going on with your old charger.

This one actually has a voltage slide switch on the back.

 

[JimPghPA]

I have a very old Sears battery charger that had a transformer with centertap secondary with two diodes, and a clockspring return timer and Amp meter. It was my dad's and he used it to charge a car battery for the trolling motor of the family rowboat.

One of my brothers borrowed it and either he or one of his kids must of connected it up wrong and fried a diode and the transformer. Those old chargers would conduct too much current backwards through the secondary if connected up backwards.

I totally rebuilt it using a bigger new old stock surplus transformer I had laying around that has more output current capacity, and diodes that can handle more current. And I used the 6 Volt or 12 Volt switch to now provide primary windings selection to provide slow or fast 12 Volt only charging and relabled it. Also added a lot of ventilation to the case, new cord and output leads. And put a resistor in series with the line power to the timer countdown motor so it sees 110 AC RMS like it was originally built for.

-----------------

If you don't connect those old chargers up backwards they are more reliable than today's chargers that use switchers as the heart of the supply. I always hated designing and working on switchers. Sure they are cheap to make and smaller. But they have capacitors that age and fail, and often are marginal on the voltage rating chosen for components resulting in short life.

Give me a simple transformer and diode(s) charger any day over a switcher.

 

[Propflux01]

10A may take the voltage on a tiny yard battery up to 14.x V prety darn fast. And it probably has high enough impedance to not take a lot of current when its there. So I suspect the circuit is protecting because its oversize and overly conservative.

Try it on a car battery and see what happens...

OK, put it on the Mazdaratti tonight. When first plugged in and turned on, it acted normally as to how I remember them working. Went to 10 amps, then slowly came down to about 4 amps. Then shut off. About 20 seconds later, it came back on for about 5 seconds. Then just did that same thing, gradually getting longer between intervals. I am beginning to think this is how the thing operates. I gotta go kill me a battery and try it from there.