1200 GS Charging rate.

[gsman1]

Has anyone any idea what the alternator should be delivering in terms of charge.
Battery was flat after left for two and a half hours after a 130 mile run, dont think I left anything on. Took two and a half days plus to charge fully with optimate.

Meter across batery when running shows 11.75 vols approx with lights and heated grips on full on tickover and 12.5 volts with no grips on on tickover. 13.5 volts at 4000rpm with grips on full and lights on.

Any suggestions as to whether these levels of charge are ok.

Going to ring dealer tomorow, and ask them to check battery and alternator.
Bike covered 18500 miles to date used every weekend.

 

[Swooper]

Battery problems

I am sure you will get a satisfactory outcome.

Glad you got home OK after the failure. At least it happened in the right place.

 

[Clive]

Probably a dodgy alternator - see http://www.ukgser.com/forums/showthread.php?t=59327 for some more info.

After mine was replaced was outputting > 14 volts at tickover.

 

[birdseye]

You would normally expect the charging voltage to be in the 14.5 region dropping back to about 13.5v when "full" - all with the engine running at a reasonable speed. The alternator is rated at 600 watts ie about 40 amps charging at max.

Sounds to me as if the equipment you have on the bike are too much for its charging circuit. Do you have any extras like lights or heated clothes? If not, did you put the bike to unusual use - there has been a prob with off road use when continuous heavy braking has flattened the battery.

With no extras and normal road use you shouldnt have a problem.

 

[Mouse]

You would normally expect the charging voltage to be in the 14.5 region dropping back to about 13.5v when "full" - all with the engine running at a reasonable speed. The alternator is rated at 600 watts ie about 40 amps charging at max.

Even though the alternator is rated at 40 amps, there will be a regulator in the battery charging circuit - to put 40 amps into a battery would explode it

 

[TheJoker]

Tickover is usually not enough speed to generate enough power to charge properly. This is probably one reason that BMW doesn't recommend the bike idling but you should get moving as soon as it has started.

As long as you've got over 12v when up at "proper engine speeds" you should be fine. Let the electrickery take care of the rest... Ride - Enjoy

 

[GAG]

Has anyone any idea what the alternator should be delivering in terms of charge.
Battery was flat after left for two and a half hours after a 130 mile run, dont think I left anything on. Took two and a half days plus to charge fully with optimate.

Meter across batery when running shows 11.75 vols approx with lights and heated grips on full on tickover and 12.5 volts with no grips on on tickover. 13.5 volts at 4000rpm with grips on full and lights on.

Any suggestions as to whether these levels of charge are ok.

Going to ring dealer tomorow, and ask them to check battery and alternator.
Bike covered 18500 miles to date used every weekend.

I have been riding for the past week, the last couple of days the battery was stuggling to turn the engine until Sunday night and click click. Put the optimate on overnight but it took 18 hours until I had a green light. With a meter on the battery the charge was 14.5 volts at 2000 rpm and with the engine off battery was reading 12.4 volts, afer a run last night, this morning battery is reading 12.2volts, I think the battery is on its way out (14 months old) . sounds like your alternator is not chatging at the right rate.

 

[gsman1]

Latetest

Three days on charge , now when start red triangle and battery symbol on display all time, third time tries to start battery flat as a fart clicking noise only, so battery knacker one feels, have a slight suspicion alternator not far behind it only showing 12.87 at 3000rpm with just lights on think should be around 14.5. In dealers on Friday for full check (if bike starts that is after another 2.5 day charge).
Oh well that life serves me right for bragging that it was going brilliantly (which it has been for last 18K) at dealers last Saturday that will teach me to keep ones gob shut.

Has anyone any idea what the alternator should be delivering in terms of charge.
Battery was flat after left for two and a half hours after a 130 mile run, dont think I left anything on. Took two and a half days plus to charge fully with optimate.

Meter across batery when running shows 11.75 vols approx with lights and heated grips on full on tickover and 12.5 volts with no grips on on tickover. 13.5 volts at 4000rpm with grips on full and lights on.

Any suggestions as to whether these levels of charge are ok.

Going to ring dealer tomorow, and ask them to check battery and alternator.
Bike covered 18500 miles to date used every weekend.

 

[Pukmeister]

Battery terminal voltage is only a rule of thumb as to the health of the charging circuit.

The low voltage is probably the symptom of the dying battery sucking the alternator output volts up for all its worth in an attempt to charge the remaining cells and dragging the voltmeter readings down, one or more cells may be on the verge of dying completely. The batterys internal resistance is probably getting rapidly higher with age/wear and tear which will also give you a false reading at the battery terminals. I suspect that the supplier of batteries for the R12GS production lines may have one or two quality issues judging by the number of owners with charging/starting faults. Touch wood mine behaves well though it is garaged and Optimated.

Fit a decent replacement battery, fully charge it then test the terminal voltage. I bet you will find it is between 12.7 and 14.5 volts depending on RPM. If not, get the alternator replaced also.

 

[ktmmark]

Can you do an amp output test as this will show if the alternator is responding to load a lot better test than volts .

 

[gsman1]

Amp Ouput Test

How do you do this?

Can you do an amp output test as this will show if the alternator is responding to load a lot better test than volts .

 

[ktmmark]

you need an amp meter ,mine clamps round the live to the battery don't even need to disconnect the battery.

 

[Ste@SSB]

Me thinks it needs the latest software update...

 

[birdseye]

Can you do an amp output test as this will show if the alternator is responding to load a lot better test than volts .

Not really - you could have low amps for 2 reasons at least, low alternator output or high circuit resistance elsewhere. The first would show up in low voltage anyway, the second doesnt affect the alternator itself.

Checking the voltage is a good initial diagnostic test and one that is easily done with a cheap digi voltmeter. But where the ammeter would come in useful is to check what drain there is when the bike is switched off.

 

[gsman1]

Solution

New battery fitted and new alternator ordered from Germany.
Rainbow comes up trumps again in more ways than one. Arrived at Dealers on Thursday to drop bike in for check and fix for flat battery and possible no charging, Ian had arranged for me to use the RT demonstrator. Got there and told sorry RT had to go to Scotland (me thinks here comes 650 Scarver, Then Dave comes up me and says loan bikes outside take it steady on the new tyres, gets outside brand new 4 cylinder K1200demonstrator 3 miles on the clock, Dave’s last words "enjoy running it in"!!!.and I still am 250 miles later.

What a fantastic dealership again.

Has anyone any idea what the alternator should be delivering in terms of charge.
Battery was flat after left for two and a half hours after a 130 mile run, dont think I left anything on. Took two and a half days plus to charge fully with optimate.

Meter across batery when running shows 11.75 vols approx with lights and heated grips on full on tickover and 12.5 volts with no grips on on tickover. 13.5 volts at 4000rpm with grips on full and lights on.

Any suggestions as to whether these levels of charge are ok.

Going to ring dealer tomorow, and ask them to check battery and alternator.
Bike covered 18500 miles to date used every weekend.