[Captain]

Can I just disconnect/connect the positive (red) wire under the seat and connect the charger wire to this terminal without harming the electronics?

I have done this a few times without any problem. I just be careful and remove the lead quickly so there are no sparks.

 

[Bill88]

I have to agree with the Captain,

But Its true its probably not the right way to do it but
I have jumped this bike twice and did not remove any tank ? just make good contact and jump it.

In the past my habits were the same with all batteries I have owned and never lost one

 

[BillB]

Hi

I have always learned that I should disconnect the negative from the battery before i remove the positive wire because a spark can harm the electronics (maybe this is wrong?). It is a litte work to get access to the battery on this bike. Can I just disconnect connect the positive (red) wire under the seat and connect the charger wire to this terminal without harming the electronics?

Charging/jumping are exactly why BMW put those lugs there (negative on cylinder, positive under seat) so you wouldn't need to remove the tank.

Regarding sparking, you aren't going to harm any electronics with that discharge. The reason you don't want to make sparks near a traditional lead acid battery is that while charging they give off hydrogen gas, which is highly combustible. SLA's and AGMs are a problem. Usually the reason you disconnect the negative terminal first, is that it isolates the battery from the chassis. That way, if you inadvertently short the positive terminal to the chassis while disconnecting it, you won't short-circuit the battery.

 

[geir__]

Thanks for Your help! It worked fine with the positive wire.

The charger will not start, but I suspect it is some problems with the negative connection.

 

[geir__]

Hi again

I still have problems with the charger. I have connected the negative wire to the bike at two different places (see picture), but the charger will not start. It just lights up (see picture), but I can not choose a program so it will not start. According to the manual, it might be because of bad conection to ground.

What do You think might be wrong?

Do I need to turn the key when I connect the charger?

 

[BillB]

Hi again

I still have problems with the charger. I have connected the negative wire to the bike at two different places (see picture), but the charger will not start. It just lights up (see picture), but I can not choose a program so it will not start. According to the manual, it might be because of bad conection to ground.

What do You think might be wrong?

Do I need to turn the key when I connect the charger?

You do not need to turn the key. If you have a voltmeter or test light, check the connection at those points.

 

[BaldyDave]

Probably just a poor ground connection. Have you tried the oversized bolt on the right hand cylinder? This is designed to be a negative terminal for running tests, jump starting and should give you a reliable connection.

Don't turn the ignition on when changing the battery, you might damage the electronics.


Sent from my iPhone using Tapatalk

 

[geir__]

You do not need to turn the key. If you have a voltmeter or test light, check the connection at those points.

Thanks for the advice! To sum up; the blue illustrates good ground connection on my bike. The red is not especially good

 

[geir__]

Probably just a poor ground connection. Have you tried the oversized bolt on the right hand cylinder? This is designed to be a negative terminal for running tests, jump starting and should give you a reliable connection.

Don't turn the ignition on when changing the battery, you might damage the electronics.


Sent from my iPhone using Tapatalk

Thanks! It did not work here either.

But I have now solved the problem. The charger must be broken. Tried another identical charger and now it works.

Thanks for all help!

 

[Wynand]

I have made a charging lead for my R9T (2015) and connected the + wire to the + battery wire under the seat and the lead's - wire to the bikes frame. I use a normal trickle charger (14V 1A) without load. I still get the feeling that the R9T's battery is struggling to start the bike... I have measured only 12.3V on the bike (without charger).


Is there a problem with my "direct" connection? Can the battery just be down hill and may need replacement?

 

[BillB]

...I still get the feeling that the R9T's battery is struggling to start the bike... I have measured only 12.3V on the bike (without charger).

Is there a problem with my "direct" connection? Can the battery just be down hill and may need replacement?

12.3V is low for a freshly charged battery. Double check your charging connections, especially your ground point. With the charger on, measure the voltage at another, distant ground point (battery - terminal is best, but a PITA to get to. Try the negative charging lug on the cylinder head.) to make sure it is reaching the battery.

How old is the battery?

 

[JohnT]

I have measured only 12.3V on the bike (without charger).

At 12.3 volts I'm surprised your bike starts at all. Do a check with the bike running and the engine turning 3,000 rpm or so. Check the voltage across the + terminal under the seat and the ground lug on the right cylinder. This will verify your charging system is charging. You should see 14+ volts testing this way.

Check the voltage the same way, right after removing the charger, engine off. Then again 2 hrs later. That will tell a lot about the batteries condition. You should have 13+ volts immediately after removing the charger and at least 12.8 volts 2 hrs later if the battery is good.

Have you added electrical accessories?

 

[Wynand]

How old is the battery?

Now going for 2 years - I think it may be a weak earth... Regards.

 

[Wynand]

... after removing the charger and at least 12.8 volts 2 hrs later if the battery is good.

Have you added electrical accessories?

Thanks! I'll check. No electrical devices connected. I'm checking for a possible weak earth.... Regards.

 

[Travellerphil]

Hi Wynand, suggestion or two..
1, check multimeter on another known good battery, not unknown for the digital display to mess up, set to auto range or 20v Dc..
2, charge bike battery until fully charged
3, to test earth.. Set multimeter to 2volts Dc setting, fix positive (red meter lead) to bike jumper point on cyl head, then fix negative meter lead (black) direct to battery negative (soft lead post on battery)
4, crank engine & observe meter readings, should go no higher than 0.4 volt, if you get a reading any more than that you have problem with connection or wire on earth side..

 

[Wynand]

Hi Wynand, suggestion or two..
1, check multimeter on another known good battery, not unknown for the digital display to mess up, set to auto range or 20v Dc..
2, charge bike battery until fully charged
3, to test earth.. Set multimeter to 2volts Dc setting, fix positive (red meter lead) to bike jumper point on cyl head, then fix negative meter lead (black) direct to battery negative (soft lead post on battery)
4, crank engine & observe meter readings, should go no higher than 0.4 volt, if you get a reading any more than that you have problem with connection or wire on earth side..

Thanks! I switched the multimeter to the diode position so that the "peep" (audio) comes up.... and I found a bad earth (as was suggested here). I fixed it and it seems the battery has picked up - I checked two hours later and without the charger attached the battery read 13.2V.

 

[Travellerphil]

Thanks! I switched the multimeter to the diode position so that the "peep" (audio) comes up.... and I found a bad earth (as was suggested here). I fixed it and it seems the battery has picked up - I checked two hours later and without the charger attached the battery read 13.2V.

Hi, must have been a really bad one to find it with the beep, but nevertheless good result.. :goodjob:

 

[Mr. Lee]

Thanks! I switched the multimeter to the diode position so that the "peep" (audio) comes up.... and I found a bad earth (as was suggested here). I fixed it and it seems the battery has picked up - I checked two hours later and without the charger attached the battery read 13.2V.

What did you do to fix the bad earth? Does that mean ground?

 

[Wynand]

What did you do to fix the bad earth? Does that mean ground?

Earth = Ground The ground lead had a loose nut... I tightened it and got a solid beep!

 

[shmalick]

hi, was it easy to attach negative hook to the screw pointed in the pic