Not charging enough. Battery slowly dying.

It could just be that the output of the rectifier is somehow not making it to the battery.

When he checked the battery, he had already unplugged the brown, so battery voltage would be expected to be down (no current to the field).

Maybe there is just a bad connection heating up and reducing the current to the battery.

loudhvx wrote: It could just be that the output of the rectifier is somehow not making it to the battery.

+1, thats the correct answer there. Sounds like it is trying to charge, but the wiring is eating the Voltage/ current. Or there is much more Amperage being used, than the Alternator is putting out. Again Amp meter load tests.
What was the system rated at for Max output Amps and Volts, at the usual 4K RPM?

Bloglos do you have any electrical items on your bike that are not stock? Dyna Ignition?
since the white is Tee'd in to the battery and load, with a higher load than output, this could be the drop in voltage across the battery witnessed. It would be nice to do a "Full Field Load test" to see the Output of his system. Followed by what the system load total is. My $5 AMP gauge will show if the output is greater or less than the load, in a couple of minutes.
Also this is why I suggested the Parallel circuit to the white output wire from the Rectifier to the battery, with a test lead. If the circuit can't supply the current needed, the result will be low voltage.
Also on this system, the Brown wire Feeding power into the Regulator would need to be at or near the voltage measured across the Battery Terminals. As this is the Supply circuit for the Field. If the voltage drops here, feeding the Field, it won't put out full power.

IIRC at 4k rpm should get 3 amps and 15 volts - there are instruciton in the pages I posted on how to test this with the reg removed - as loudvx suggests.

"at 4k rpm should get 3 amps and 15 volts"
Look again, it Has to be much more than3 Amps for the output. Max rated is more like 18-20Amps and 15v.

Everything is stock. I have nothing attached that would eat up current. I was a little overwhelmed with the posts from yesterday, so we think that the wiring from the rectifier post whitewhich connects to white/red and goes back to the battery might be the cause?
Or should I do the test again but jump green to brown?

Or should I check the charging system a t the battery by jumping directly out of the regulator white to positive on battery? Would this eliminate faulty wiring to the battery in the harness?

First test is to check battery voltage while running, then jump green to brown while running. Check that the voltage goes up to 14.5v. Rev it lightly if necessary, and take note of the RPM where it gets to 14.5v. Make sure battery does not go above 15v.

Some basics, and how I would proceed.

Remove battery.
Assure fluid levels are correct.
Add distilled water if needed.

Charge battery overnight on the bench with 1~2 amp trickle charger.
Have battery load tested.

If battery passes the load test, re-install it.

Assure cable terminal connecters are clean and snugly fastened to the battery posts.
[Don't reverse these -- Duh]

Assure integrity of the connection where the negative battery cable attaches to rear of engine.


As the rectifier must be properly grounded, would assure integrity of ground wire from the rectifier and its connection to ground.
Could use an ohmmeter to assure continuity through ground wire from rectifier to frame or engine.

Now it's time to measure voltage across the battery posts at 4000 rpm, and look for 14~15 volts, which indicates that the charging system is indeed charging.

If loudhvx says anything different, go by what he says.

Good Fortune!

Post up any and all progress, as everybody wants to help you get it figured out.

Motor Head I was just going by what the FSM says on the bottom fo the 3rd page I posted above it indicates that at 4k one should read 15v and 3amps. I know that the FSMs are not perfect - as many issues have been noted here and on other sites with some of the data and instructions in them - but this ones does indicate those values.

3 Amps is not much power, I don't have the book for checking the spec. But those Alternators have got to put out like 18Amps at full Field, 3 wouldn't be enough for the Headlight.
Maybe the part you're reading is not Max Rated Output?

Agree it is about 45 Watts not an overly large amount. I have read somewhere, that the system should charge at about 1/3 of the amp/hour rating of the battery. IIRC the batteries for the early 650s have an amp/hour rating of 10. So 3 or a little over should be about right.

I do not think this test is measuring total output of the system, but I could certainly be wrong about that. According to the FSM the test is done with a amp meter in series to the battery (on the neg side) with a bypass cable added to protect the meter from back current when the engine is not running fast enough charge the battery. You also use a volt meter across the the 2 battery terminals. The green and brown wires are disconnected from the regulator and connected to each other. In essence by passing the regulator and used the sense wire to power the field coil. You then run the bike at 4k, disconnect the bypass for back curent protection of the amp meter, and read the meters.

That test sounds like it is full Fielding so it would be capable of Max Output. But the measurement sounds low. I wonder if, with the bypass, some of the current is looping around the meter, giving the lower reading. 3 Amps is used up pretty quick by Ign, Lights, horn, blinkers, recovery from an electric start. Any one of those circuits could take at least 3 Amps to operate.
this would work in the opposite as well, if the factory wiring has a loop added from the Rectifier to the Battery, on the white wire, with the increased path for the current to flow. A rise in current to the battery would occur. Thats if there is a resistance in the factory loom. Can also quickly check for a poor ground the same way, add a loop with a test wire, and check for an increase in flow.