BMW R1200RT/R1250RT Forum

Excluding Li-ion, there are Wet Flooded, AGM and GEL type batteries for RT's. OEM fit for both Hexheads and Camheads is a GEL type battery. From what I've read elsewhere, GEL batteries typically have a very low discharge rate, as low as 0.75v in 6 months. This could well be true, when my bike is stored for 5 months, I regularly charge the battery. The battery charger almost immediately goes from charge to absorb to maintain voltage and current, indicating very little voltage drop over time.

Whereas, on my XJ650 which has a traditional Wet Flooded battery, if the battery is left for the same period of time, the charging takes longer. Obviously because it's discharged more and has a lower starting voltage.

I've no experience of motorcycle AGM battery types.

What type of battery is fitted to your bike and how do you find the charging requirements to be.

All of mine have been AGM for many years now and way better than the old flooded. 1-2% discharge per month is typical. Some more info here:
https://www.power-sonic.com/blog/the-co ... batteries/

60Aviator wrote:Some more info here: https://www.power-sonic.com/blog/the-complete-guide-to-agm-batteries/

Thank you, that's a useful link.

Been thinking about replacing the Wet Flooded with an AGM battery on the XJ650 next time it needs one.

Not sure why the OEM spec. is GEL on the Camhead, it's one of only a few out there for motorcycles.

(51913  Exide  GEL 12-19  186L x 82W x 173H  Gel 12V 19Ah 170A)

The Yuasa YT19BL-BS (AGM) is a direct replacement for the OEM Exide, Yuasa Introduces YT19BL-BS AGM OEM Style Battery for BMW Motorcycles | Cycle World