Hi Guys,

I am having some brain freeze trying to figure this out. I am facing a charging problem, I charge off a booster pack then leave her overnight and she starts fine in the morning. Leaving work I have to push. It's not draining the battery, current draw shows a zero with ignition off and it holds charge overnight. This then excludes battery (which is new) and electrical draw (there is none) so it must be a charging issue. I measure 13.7v at idle and 14.3v @ 3000rpm so there is output from the alternator. I then decided to test alternator current output since I was told the 3.2ohm I measure across the white and black to the alternator is too low and the alternator is drawing more current than it is producing. I set up as follows



With ignition on I get a zero reading so I have definitely isolated just the alternator output amperage



Running I get around 8A after starting which drops to around 6A after the initial starting power is replaced in the battery,



then after running for a bit it spikes to 15A as the fan kicks in



To my mind then the alternator certainly has good output current as well as voltage.

What am I missing here?? Please help, this is hurting my head. This bike has a Mk1 alternator and a Mk2 regulator but with the readings I am getting I can't see a problem, the wiring has been altered at the plugs to match up.

 

Other readings taken

Between yellows 1.2 ohm
Between black and white 3.2 ohm
Battery voltage ignition off 12.2v
Voltage between black and white. Ignition on 10.9v, idling=8v, @4000rpm=3v

 

Did you test the voltage at the battery when you up the rpms? I only ask because I was having a similar issue, everything checked out fine but I had checked the voltage going to the battery at the starter relay (the red and if I remember correctly white wire going into the relay from the r/r).

After boggling my mind for a couple hours I checked it at the battery and it was showing no spike in voltage when I upped the rpms so I bypassed the starter relay and my issue was solved.

Hope it turns out to be something simple for ya, I know I hate having to spend money on parts since the manufacturers think they're made out of gold

 

when you say you have to push it after work, is the battery flat again, the reason i ask is as you say the bike will hold charge over night whilst nothing is running, but when you ride her the following day she flattens the battery, try seeing what output you get to the battery with her running and your lights ect on just to check if your alternators keeping up with its demand under load.

 

Battery voltage comes up to 14.5v or so at higher revs. Yes, I am push starting because the battery isn't strong enough after a ride to restart. The battery can hold a charge as it proves overnight if it is charged for an hour when I get home at night. Push starting a CBR1000F is no joke, it feels like a CBR100000F after a full day at work

It's charging while running, battery going flat while running, nothing wrong with battery...time for an exorcist?

 

this may help a bit

http://www.electrosport.com/media/pd...ng-diagram.pdf

 

You may have a dead cell in the battery - OR the regulator isn't allowing sufficient current to the battery.
Your readings sound fine, and not a problem with the stator/alternator.
A battery with a dead cell could give you those kind of readings.................Replace the battery with a known good one and take a reading across the battery terminals at +3000 RPM - you should get around 13.5 volts or more. Then check the ignition voltage with the engine off - should be +12.2 or more. When the bike has been running above 3000 revs for around 30 minutes, check the readings again, both engine at +3000 revs, and engine off. If the charged battery reading has improved above the original value ie 12.2V or more, then the battery is charging. If not, the reg/rec could have gone out.

 

Thanks guys, I think the first step is to take the battery back to the shop I got it from and get their take on it. Hopefully they swop it out without a fuss. Only 2 months old...

 

Turns out the battery is ok. Starter motor isn't well. Needs around 14v to spin with enough gusto. Will clean up my spare one and drop it in when its ready