Alternator Charging Question

[Steverino]

Hi Everyone:
Here is a short video of the ammeter with the motor running. Is this typical? https://www.youtube.com/watch?v=cDQVjKNTBYY
Thank You
Steve

[NobleHops]

In short, yes. The meter reads 2-3 volts low. Do a few searches and you'll find a thread by KoolBiker where he bypasses the wiring harness to put the meter directly on the battery and it becomes pretty darn accurate.

If you want to measure the performance of your charging system, do it with your voltmeter at the battery, see what the offset to your meter is for your bike and make a mental note.

Last thought - does it read 12ish volts (at the meter) at 4K RPM? It should if your charging system is working well.

[Steverino]

Thanks Nils:
I checked her and the ammeter jumps up to 12 just as the Tach passes 4200. I appreciate your help.
Steve
I've enjoyed reading this forum the past few months and learning a lot about my CBX. Thx Everyone!

[Larry Zimmer]

Agree, that's somewhat common after just starting the bike. After it has run for 10 miles, or so, it should read 13 down to 2K if you're not applying brakes. One other comment, Steve. Given I don't know the miles on the bike, consider checking the wiring harness connector, behind the right side panel, for ANY corrosion of the contacts. Pull it apart and clean things good. This one is a significant source of resistance/current loss in the charging circuit. From there, use the other references mentioned.

Have a great ride.

[Rick Pope]

Just a reminder..... Voltage is not necessarily a good indicator of whether the alternator is charging, rather it is showing the amount of energy in the battery. Amperage would show how much the alternator is actually producing.

So, to get a clear picture of what's happening down there, we would need both a volt meter, and amp gauge, with pick-ups in the correct locations to avoid false readings.

Bottom line is, don't be concerned if your stock meter indicates low voltage for a bit on start-up. As long as it comes back up with a few miles, you're fine.

[daves79x]

Especially on the late models it seems, you have to run down the road a few miles sometimes to pick up full voltage, depending on the initial charge state of the battery. If you never plan on riding the bike - you'll likely never see the gauge go fully to 13.5v or so. Just do as has been suggested, put a good voltmeter across the battery terminals and verify you're getting proper readings there.

Dave

[Arundel2]

What would you suggest if my volt meter reads 13.5 volts from cold then slips when bike is being ridden down to 10/11 volts when hot ? I have once run out of battery charge and only managed to get in the driveway before bike died. This was after a ride of about 1700 ks .
A magazine i have from England featured the cbx and stated , Reassemble alternator clutch plates with Loctite adhesive. Leave overnight to dry and then your cbx will actually
charge. Is this a viable fix or will it cause other problems ?

Mike
New Zealand

[daves79x]

I'd suggest checking your rotor for continuity - should read near 4 Ohm. That's what it sounds like to me. Then resurface your clutch plates by hand and shim the spring with another washer. Rotors can be rewound.

Dave

[Arundel2]

Thanks for your advice Dave.

Mike

[Arundel2]

Had a bad ride today and had to be rescued.Got about 30 miles from home and noticed the voltmeter had dropped to 11 volts down from 13 volts.I did not worry as this had
happened at other occasions.By 50 miles volts had dropped and kept dropping so i rapidly headed for home.I did not make it. Battery ran out of juice.
Once i put a fresh battery in was able to ride home.
Upon investigation i found the lead acid battery was bone dry.With newer battery in bike and running my multimeter gave a 13.80volts reading at 1200rpm idle.At 4000 rpm
a reading of 14.5volts.Is it possible the clutch is slipping so much that the battery is receiving no charge? But what about the dry battery? The battery had not been checked
for at least 3/4 months.Could these issues be down to clutch and regulater/rectifyer? I am at a loss now as to where to start. Please help!

Mike

[daves79x]

First, get rid of the lead/acid battery and get an AGM. Back in the day, I had to add water at least once a month to the old batteries, when I was running the bike a lot. CBX alternators/regulators will put a pretty hard charge into a slightly under-charged battery and boil even more water out. Your alternator may be indeed be fine, but get a good - quality battery and check the charging system out completely.

Dave

[Larry Zimmer]

Further to Dave's note, your lead-acid will lose water even sitting on a Battery Tender. I would suggest that, being as dry as you mentioned, it wasn't going to charge regardless how good your system is. As Dave said, GET THE AGM! Another benefit, they are MUCH less susceptible to vibration -- another battery killer in motorcycles. And, you'll find they crank much better than a lead-acid.

[Arundel2]

Thank you Dave and Larry for your wise and helpful responses!
New US spec Motobatt gel battery on it's way.I originally ordered a Motobatt but was presented with a lead/acid instead.My fault for accepting it i suppose.
I have them in my other 3 bikes with no problems to date.That is to say Motobatt batteries.
Will keep you updated.

Regards
Mike

[EMS]

New US spec Motobatt gel battery on it's way.
Regards
Mike

Is it a Gel or an AGM battery? Gel batteries require different charging than lead/acid or AGM. AGM is essentially lead/acid. Just that the acid is soaked up in the glass mat between the plates which makes it a "dry" battery as opposed to a "wet cell"

[Arundel2]

Just spoke to supplier and yes the battery i have coming is an AGM type.