Reg rec current drain

[freeridenick]

My new battery is dead. Having found it dead before heading to the MOT I jumped it and got the bike going. At the MOT station it was started twice and then nothing when I came to leave. Another jump got me home.

The battery got changed, didn't take very long, and I checked for a parasitic drain. The reg rec was the only thing that showed any. There's nothing else really that it could have been.

So is this normal? I contacted the place I bought it from and they have suggested it can be. Having tried to ride the bike yesterday and found the battery dead again I've also contacted the battery manufacturer as it feels like it's a dud but if any of you gifted electronic experts can help I'm all ears

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[sirch345]

Have you checked what voltage is showing at the battery when the bike is running Nick?

Chris.

[freeridenick]

Have you checked what voltage is showing at the battery when the bike is running Nick?

Chris.

Yes Chris it was around 14.4v.

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[sirch345]

Have you checked what voltage is showing at the battery when the bike is running Nick?

Chris.

Yes Chris it was around 14.4v.

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That sounds good, so the alternator and rectifier/regulator must be doing their jobs okay.
As for a parasitic drain, I’m not sure what is acceptable, although when I checked my Storm just for interest some time ago I did have a small drain. I put that down to the odometer that retains the miles covered on the trip meter, as if you disconnect the battery this zero’s itself, so it must ( unless someone else tells me different of course) use a small amount of current to kept that working when the ignition is off.

You could disconnect the battery, check voltage with your multimeter, then in the morning or later check the voltage again. If the battery is not holding it’s charge you should notice a drop in the voltage,


Chris.

[tony.mon]

Pull all of the fuses and check again.

A reg/rec has two functions, one side (the rectifier) allows current to flow one way only (into the battery) from each of the alternator's three windings using a diode, and the regulator part turns any excess voltage over what's safe for the battery to be turned into heat.

So for there to be a parasitic drain either one (or more) of the diodes is faulty or the regulator is faulty and turning battery voltage at less than 12v into heat.

Meter out the alternator windings first- Haynes gives the values, they should all be roughly equal.

[freeridenick]

Pull all of the fuses and check again.

A reg/rec has two functions, one side (the rectifier) allows current to flow one way only (into the battery) from each of the alternator's three windings using a diode, and the regulator part turns any excess voltage over what's safe for the battery to be turned into heat.

So for there to be a parasitic drain either one (or more) of the diodes is faulty or the regulator is faulty and turning battery voltage at less than 12v into heat.

Meter out the alternator windings first- Haynes gives the values, they should all be roughly equal.

Cheers Tony. Resistance of the alternator windings are all 0.6ohms, measured between each pair of contacts. That's over what the manual says is standard (0.2 to 0.5ohms), but not much so I don't know whether it's OK or not. The manual says to replace the alternator if it's out of spec.

Checking the same resistance in the RR and it was massive. Even on the highest setting it only flashed up a reading before going to 1. I feel like I must have done something wrong but the same thing happened multiple times.

I also whipped the car battery out and connected it to the bike. That gave me power and when disconnected I got just over 5v across the bike battery but it wasn't stable, reduced down to zero in less than a minute. So the battery is definitely dead, right? The main problem is I still don't know why.

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[freeridenick]

I forgot about the resistance in the meter. That's 0.4ohm so subtracting that from the alternator reading leaves me in spec. So it's the battery and or RR.

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[tony.mon]

Try disconnecting the alternator and connect the car battery instead of the bike battery. Watch the voltage, and if it drops while you're watching it must be the regrec or a short somewhere.

If it doesn't drop, reconnect the alternator and see if it drops then.
If it still drops when both regrec and alternator are disconnected you have a short to ground in the harness somewhere.

[freeridenick]

So after a few attempts to work out what's going on this is where I'm up to:
Reg Rec is being replaced under warranty. Milliamp draw means it's not right.

I've been through the starter wiring and there's continuity from the starter solenoid to starter and the same to ground. Not sure the later sounds right.

Starter spins when connected directly to a battery but is hard to turn by hand. It also turned the engine over well enough when the plugs were out.

Car battery connected to the bike and it turns over very slowly. Solenoid ground wire is fine but battery voltage from red/yellow to ground is very low. Could just have been my bad terminal connection so I need to test again.

The solenoid clicks but could be duff. I have a couple of others but neither was any better. I'm edging towards it being the starter as it was blasted before coating. I cleaned out the inside but it could we'll still have been full of crap. Starter solenoid could be shagged too if the starter is drawing too much current I guess.

So I think I'll pull the starter apart and see what it's like inside. I wasn't always getting power to the dash when I connected the car battery though so I think I'll be replacing the solenoid too.

Edit: with the starter turning the engine over with no compression, but not really when the plugs were back in would that indicate it's more likely the solenoid not allowing enough current through? I've gone round in circles so much I've confused myself.

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[tony.mon]

The starter should be checked to ensure that the terminal post is insulated from the starter motor body, there should not be continuity from the post to ground.

The post should have two fibre washers, one inside the case and one outside, and the terminal bolt should be insulated by a short length of plastic tube as it goes through the casing.

The terminal post has a square head inside the casing that prevents it turning as you unscrew the securing nut for the cable, but because the nut corrodes in place due to its position behind the front wheel it can damage the terminal post or twist it inside causing the post to contact the casing.

Next, examine the cable carefully. They often corrode inside the cable sheath just above where the terminal ring sits as it connects to the starter motor. To check this, you can meter it out, or simply fit a length of piggyback cable- it needs to carry a lot of current so use something thick, such as 30 amp cooker cable, to piggyback your existing one. That won't be thick enough to carry the full starter load by itself, but if your starter now spins noticeably quicker it shows that the cable isn't able to carry the full current.

[freeridenick]

New starter solenoid on order. The old one was probably there from new so might as well be replaced. Starter checked and all good except I get slightly different continuity readings between commutator bar pairs. Most go down to virtually zero but a few are around four. Checking the same on resistance most are 0.6ohms but a couple are about 1ohm. Is that to be expected. No crap inside the casing so that's not the issue.

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[freeridenick]

The reg rec has been replaced under warranty and I've finally got the bike turning over - seems like a combination of old starter solenoid and dodgy jump leads. Now I've got no spark. I'll have to find a day when I can pull the bike out of the shed and into the garage for a proper look at the wiring.

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[sirch345]

The reg rec has been replaced under warranty and I've finally got the bike turning over - seems like a combination of old starter solenoid and dodgy jump leads. Now I've got no spark. I'll have to find a day when I can pull the bike out of the shed and into the garage for a proper look at the wiring.

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Sometimes it can feel like one step forward, two steps back Glad you have finally got the bike turning over, so your are making progress

Chris.

[tony.mon]

The reg rec has been replaced under warranty and I've finally got the bike turning over - seems like a combination of old starter solenoid and dodgy jump leads. Now I've got no spark. I'll have to find a day when I can pull the bike out of the shed and into the garage for a proper look at the wiring.

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Check fuses first, it's easy to pop a fuse when jumping a battery.