New battery

[Olgry1]

Well after maybe 32k miles and 3 years it appears that my battery needs to be replaced. I just returned from a 12 day business trip and in that time the battery was almost totally flat and would not turn the engine over. The bike was not ridden for a couple days before that so no charging in 2 weeks. I have left the battery for a month before and it would start first try.

So I looked up the OEM battery and I am seeing nominally $190-$200 online for the BMW Motorcycles AGM Battery (by Exide I believe) 12volt 12AH Part # 61218394179. I may ask the dealer, for a laugh.

Anyway, as is my wont whenever I have to replace a part I look to see what is out there that might be better. Lithium Ion batteries are popular because of the weight saving as well as the alleged performance advantage over lead acid batteries. AGM batteries were the new kid in town before the LI-ion batteries hit the market, with the latter being significantly more expensive (especially in larger sizes). Not so much for motorcycles ... I am seeing the Shorai Lithium Battery LFX21A6-BS12 for $207 at Revzilla. However I am concerned about some of the negative reviews especially with regard to cold weather performance. That is quite the opposite for my AA Energizer lithium batteries in my camera which last forever and wok well in the cold.

Exide has a PDF brochure that compares [their] battery types

Have any of you replaced the battery on your RS? If so what did you get and why? Any recommendations?

I installed a Shorai battery (4-5 lbs? weight savings) on my RS earlier this year. As you said the advantages to a LI battery are lighter weight and subjectively when warm, more cranking power upon start up. The disadvantages are the cost, the cold start performance and in my opinion, at least for the Shorai, the need for a Shorai charger. I don't remove my batteries (also have a Shorai in the 1600 GT - 13lbs actual weight savings) during the winter. The charger maintains my batteries through the winter as I typically rotate the charger between the two bikes.
When and where I can I like to reduce the overall weight of my motorcycles. Every little bit of weight reduction and or power enhancement helps the bike's performance...I guess the same would hold true for me
Periodically Shorai has a factory direct sale with 20% off their list price around the Christmas holiday season.