Topic: Beginner Charging System Question *Updated*

[oahmed389]

I was checking my charging system and I want to make sure that I did the basic test the correct way. I checked the battery voltage (freshly charged) before putting it on the bike. I got 12.9V. Then I put it in and checked the voltage by touching the terminals, still 12.9V. When the bike was idling at 1500rpm the voltage increased to 13.2V and when rev'd to 3000rpm increased to 14.5V and at 6000rpm was around 13.8V. After turning off the bike I checked the battery voltage again and it was 13.02V.

From the reading I've done this indicates that the battery is charging when I run it at rpm's over 3000rpm, right?

Please let me know if I did this right and if my conclusion is right. Thanks in advance.

Update:

So after the original battery kept dying within a few days of charging, I bought a new battery. I charged it yesterday and then put it in today and went for a ride. I only rode it about 10 minutes to a friends and quickly (1-3 min later) went to start it back and it wouldn't start. It turned over slightly but wouldn't crank. After waiting for maybe 5-10min it started right up. I then rode back home to look for a jumper cable since I was riding with a friend and came back down after 5minutes and it started right up again. We rode for another 15 minutes and stopped for a minute tried to turn it right back up and it wouldn't start. So after waiting a few minutes again it started up easily and then rode it home. Once I got home I tried starting it back up after 1-5minutes it wouldn't start. Then went back 15 minutes later and it started right up. Thoughts? Because I'm confused by this behavior

[TwoTired]

Sounds like a good system to me.

Anything higher than 12.6v is a charged battery and indicates non-depletion.  Any surcharge will bleed off over time.

[oahmed389]

So if you looked at your system got those results you'd say everythings good?

[Don R]

Eeeyyyup.

[Shane72]

I would be happy with those numbers any day of the week.

All the best,

Shane

[oahmed389]

Updated - See original post, I filled it in there

[scottly]

Are you saying the electric start cranks the motor over slowly, or not at all, when hot?

[TwoTired]

What is the battery voltage when it doesn't start?

What is the battery voltage while the starter motor is engaged?

If you pull out the headlight fuse, will it start?

[oahmed389]

Scottly: the starter turns but won't catch and crank up when it's hot.

TwoTired: I will ride it this afternoon and check the voltages and the fuse and post back. Should I be checking amperage or volts?

[Shane72]

If the starter motor spins, but doesn't catch and crank the engine--sounds like the issue is related more to the starter motor system itself, not necessarily the charging system at all.

I agree that battery voltages should be checked while under starting load, in addition to while running, as well as off and at rest.  Rule out one whole potential problem at a time before fixing what isn't necessarily broken.

If the DC voltage drops down past 10 volts or so when actually cranking the engine, that's a problem.  If it stays above that, your battery is probably fine.  A load test at your local battery store will tell more of that story than this test, but it's a start.

Also, another poor man's test of the charging system (if you don't have a voltmeter) is to see if the headlight gets brighter as the engine is revved, returning to a bit dimmer at idle.

My motto:  "If it ain't broke, fix it 'till it is".   

All the best,

Shane

[oahmed389]

So took for a spin and thought I'd update you while I wait for a friend to come jump me. Before the ride with the bike off voltage was 12.17V at idle it was a little higher at 12.4V then at 3000rpm it was 13.something. I rode it to a parking lot and stopped. Tried starting it right up, nothing. Checked the voltage a few minutes later and it was 11.77V. After about 30 min it cranked right up. Started riding home and after a few miles the idle got sketchy and lights dimmed then died. My friend took the voltmeter so I can't check it now but after 5 minutes here when I turn the key the lights come on bright but when I press the starter it just makes a single click. Thanks for your help everyone

Oh and when I crank it the voltage was 9.6V

[Spanner 1]

Another bike with a crappy main ground connection ?......... have you shone-up the battery terminals, main ground ring terminal ( including the frame where it connects ), the 2 x connections on top of the solenoid ??

[oahmed389]

That was going to be my first task, clean all the connections then check voltages again.

After that from what I read it might be the starter motor?

[Jerry Rxman Griffin aka MuthaF'er]

Have you checked the stator and field coil? Simple to do. You're checking for resistance values. Replace the connectors (both male and female) when you do this test! They burn and loosen.

Have you checked your rectifier? Again simple to do. You're checking for continuity.

These are the things that produce AC voltage electricity then turn it into DC voltage for your battery.

Speaking of battery, and I know you have a new battery, if those things check out take your new battery to a place like Advance Auto Parts and have them do a free load test. My old battery had been on a tender and showed good voltage but had next to none CCA's compared to new.

Then there is the voltage regulator which tells your field coil when it needs to work to produce additional voltage. Have you checked it?

If all of this checks out good then start checking your wiring. Ground was mentioned. Connectors were mentioned. Buy a kit and replace all of them. One VERY small voltage drop across one connector is greatly multiplied if they ALL are the same. Possible bad wire in the harness? Check before and after voltage at each end. Ignition switch?? Check before and after voltage. It carries a lot of current and if it's compromised then there can be a big voltage drop for your entire system.