My CB77 No Longer Charges the Battery

[sarals]

I'll have the battery load tested tomorrow.

If it's okay, I'm going to have to fall back and think.

[G-Man]

Graham, I'm beginning to believe the stator coils and rotor are okay. I am getting 55.6 VAC across the yellow/brown stator output, and 58.3 VAC across the pink/brown stator output. When I connect the Radio Shack bridge rectifier directly to the stator leads, with the battery in the circuit, I get battery voltage at the + terminal on the rectifier. When I disconnect the battery and connect a 12V lightbulb, it lights right up, and when I rev the engine, the generator will burn out the bulb (it does that because I have the pink and yellow legs combined). So, there is no issue with the output from the generator, as far as I can determine. I've checked my ground and hot connections on the battery, and they seem okay. All of the lights light up on the bike, and the engine will run off of the battery. But, the system won't deliver ABOVE battery voltage to the battery.

Bad battery? It's a lead acid battery, not a gel.

Two thoughts ---

1) Did you measure the voltage across the bulb?
If you could use successively higher wattage 12v bulbs across the battery terminals, you can get a load characteristic for the charging system.

Higher wattage (more current) bulbs will drive the system harder and the voltage will go down as the wattage goes up.

2) If you charge the battery right up on your charger and then put it in what does the voltage look like? With the engine on and off?

Happy hunting

G

[brewsky]

It is sounding more like the battery now. (hopefully)

Checked battery acid level?.....add distilled water if low, bring to full charge (12.7v or so) and see if it will hold that voltage level for several hours.

Then re install and check charging voltage.

One more possibility...loose wires at switch connections?

Still hoping for something simple..

[sarals]

Graham, I forgot to include the voltages with the bulb. It starts at 12.8 at idle and at 4000 RPM it's 14.2 and the bulb goes "pop"! With no load across the + terminal and ground on the rectifier (and the Podtronics regulator/rectifier) there is no voltage. So, the generator is genning.

I'll try a higher wattage bulb and see what I get.

Brewsky, I think you're right...battery.

I've been over and over and over connections, and they're fine. If I keep yanking and prodding at them they won't be!

I overcharged the battery a few months ago on the charger, and it boiled off most of the fluid. I refilled it with distilled water and thought nothing of it. I hadn't been running or riding the bike enough to get a feel for how the charging system or battery behaved. When I did start stressing the battery by riding it, well. Trouble.

I'll have the battery load tested today. Hopefully that will give me an answer.

[jleewebb]

I'd recommend you go ahead and spring for a Motobatt MB9U agm battery and a battery tender...available through Amazon...I went through two wet cell batteries in two years after I got my bike together...more cranking power and doesn't mind sitting up, just put it on tender before riding to bring it up to full charge...

[G-Man]

Sara

Looking good on the alternator! If you can get to 14v and blow the bulb then the alternator is probably OK. More load with a higher wattage bulb will prove that.

G

[sarals]

Well, things are looking up.

I had the battery load tested and then charged, and load tested again. It's fine. I checked all of the wiring; from the stator coils to the main loom, from the main loom to the regulator/rectifier, from the regulator/rectifier to the ignition switch, and from there to the battery and the main fuse. I cleaned spade lugs, bullet connectors, and battery lugs. I checked all the grounds. I hooked everything up, put a 25 watt bulb across the battery (the battery was at 12.4 volts), started her up. The bulb lit, the battery voltage dropped to 11.9 and then stabilized at 12.1 and never got any higher. I took the battery out of the charging circuit and placed the bulb across the ground and the positive from the regulator/rectifier. 11.8 volts. 12.1 - 12.3 when revved. Drat. I put the Radio Shack rectifier in the charging circuit, and put the bulb across it's DC output and ground. I started her up, and had 12.4 volts at idle. I revved her up, and the voltage went to 13.7!

I removed the Podtronics regulator/rectifier from the bike and installed the Radio Shack rectifier. The battery was sitting at 11.9 volts. I left the meter across the battery and started her up. The voltage went to 12.1. I revved her to 4000 RPM and the battery voltage started to climb. When I shut her off after five minutes, the battery was up to 12.4 volts.

It never would climb with the Podtronics in the charging circuit.

I'm hoping I fixed it.

I'll have to see if I can get the Podtronics replaced.