BMW R1200RT/R1250RT Forum

Got it in one.

Ok think we have done this to death. Everyone believe what they want to. I'll carry on doing what I do and take the advice of Optimate and my experiences and others. There is nothing special about BMW batteries. The good thing is everyone has the ability to make their own decisions. Just do your own research. 

Casbar wrote:There is nothing special about BMW batteries.

Very true, they are made by Exide.

Very true, they are made by Exide.



It's not the batteries that can cause issues it's the bike.  I'm not sure if BMW are still unique in using Can/Lin bus wiring but damage that in any way and the repair bills will be huge.
Let's all agree to call this one Case Closed.

Levisp wrote: Sounds good to me. Have same charger. The two greens show unit on and in maintenance mode. The orange 0.2 amp is current charge setting. This varies from 0.2 to 0.8 amps. When in maintenance mode it goes through various cycles to keep battery in tip top condition without any degradation. If you can stay awake long enough have a read on the manual. Not easy to understand but does explain the various cycles and lights. Mine is showing the same lights.

I agree with Levisp. I'm an electronics technician but gave up understanding the sequence of lights on the O4 and the manual is better than cocoa for a good night's sleep. I've had mine for about 7 years and it's been faultless. I couldn't justify swapping it for the BMW canbus version so I fitted the leads directly to the battery.

RTman10 wrote: I'm with Jim.  Modern chargers might be designed not to damage batteries if left on but there is absolutely no need on a bike like an RT to do it. Think of all the penny's I save on my electric bill.

I have never connected one of these infernal machines to my RT.  It just sits happily in the garage when not in use and has never shown any sign whatsoever of needing charging.  Starts every time...


I did use one in the past on both my Moto Guzzis (Optimate 3 I think it was).  It fried the battery on more than one occasion...

Richard I guess you use your bike all year round on a regular basis which would mean you have no need for a battery charger. However if you have to store your bike for any length of time then a modern charger will keep the battery in good condition. However even in these conditions there really is no need to leave them on charge all the time. So for those watching their electricity bills charging for a couple of days each month is more than sufficient. As for frying batteries modern chargers won't. On the other hand leaving a battery in a state of deep discharge will differently kill it.

Levisp wrote: Richard I guess you use your bike all year round on a regular basis which would mean you have no need for a battery charger.

That's true - all year round use for me...

So, I have now started to follow the wisdom of the forum members and do not now leave my RT on the Optimate. I use it regularly, so no adverse impacts as yet. I do however keep my Harley on the Optimate continuously as it doesn't get used as frequently as the RT

Casbar wrote: I have now spoken to Optimate, all is good, it is behaving as expected. And no issues whatsoever with connecting to the aux socket, that is what the BMW Canbus model is designed for.

I have just purchased a 1200 RT SE 2010. I want to get a trickle charger. Are these Optimate4's the recommended one to plug into my bike??? Others to consider? Tim

fimfie wrote:Are these Optimate4's the recommended one to plug into my bike??? Others to consider?

Yes, the Optimate 4 (BMW version) will plug into your bike.

This thread on Battery Chargers may be of interest, https://1200rt.com/viewtopic.php?t=9

Thanks I just ordered one.