1985 G1 36V Charge/Electric Problem

[Automobilist]

Our otherwise very reliable Yamaha G1 started having serious issues.

The old analog Lester charger appears to be putting out 36V. When I plug it in to the cart, the voltmeter on the cart only shows 30V, and never changes no matter how long the charger is plugged in & on.

The cart will then run for a very few minutes before it almost totally bogs down.
Batteries are a good 5 years old, but seem to load test ok.

So... Batteries? Charger? Internal wiring problem?

No shops will work on it because it's so old, but I would really like to keep it running, it's a neat cart.

Thanks...

[augiedoggy]

I'd start by checking each battery.. then try charging two together in pairs with a car battery charger.

[nickdalzell1]

How many amps does the charger claim it's puttinng out? It should be somewhere around 15-20. If it's only going to 5 or lower, the capacitor inside the charger has gone bad.

You should be seeing something closer to 42V with the charger on and a multimeter testing the cord without it plugged into the car.

Personally, I am happy to work on old stuff. Old = repairable not disposable, and especially older chargers. I'm young but I despise anything modern. modern just takes longer to diagnose and there's more points of failure, no benefits to customer, more expensive, and with modern chargers, made in China disposable garbage.

If you lived closer to Owensboro, KY, I would be more than happy to look at it.

[Automobilist]

Thanks, guys. I'll check both those suggestions.

While I'm good working on old cars (have a 1952 MG TD & a '73 Mercedes 450SL) I'm weak on electrics. I tested the charger by simply putting multimeter leads on the output plug prongs. Is that the correct way to do it?

[nickdalzell1]

Yep, if it's got a timer (with a knob) you can do that. You should be seeing something like 42-43V like that, not 30. What does the ammeter show when you plug it into the cart and turn it on? It should go to 15-20 and eventually settle down as it charges, but if it's only going to 4-5 amps, your capacitor inside is shot.

[Automobilist]

Checked the charger again, right at 36V output.
When I plug it into the cart, the ammeter on the charger doesn't move. I recall it used to show a bit over 15 amps. Now, nothing. The big fuse looks intact.

[nickdalzell1]

Internal capacitor failure. It's the large metal can in the charger. It would have a reading in MF or Micro Farads, something like 6 or 20 or some other reading printed on the side. You'll have to replace it. Be careful, bad or not, these things can hold a whollop of a charge.

The big fuse won't blow unless one or both of the diodes inside the charger fail or short.

[Automobilist]

That was it. Replaced the capacitor, charges fine now.

Thank you, really appreciated...