The dreaded "what battery would be best" question.

[Mr_Canoehead]

My original BMW AGM lasted 6 years but started to get a bit weak - so I tried a Shorai, didn't work at all on my GSA. Now I run a PC680 and have had no issues over 3 years.

I have a Noco 4 bank trickle charger that is set to AGM for the PC680 and seems to work well.

I have been watching the posts on the VR mod for a while. Does anyone know if BMW raised the voltage when they went to a factory AGM or is the mod still recommended?

 

[roger 04 rt]

I looked for it once and found that some of the R1200 bikes (maybe the GSA) used AGM and when they did used a higher-voltage regulator. I can't remember if the R1150GSA did. But yes, BMW tailored the VR voltage to the battery.

 

[gsaddict]

My original BMW AGM lasted 6 years but started to get a bit weak - so I tried a Shorai, didn't work at all on my GSA. Now I run a PC680 and have had no issues over 3 years.

I have a Noco 4 bank trickle charger that is set to AGM for the PC680 and seems to work well.

I have been watching the posts on the VR mod for a while. Does anyone know if BMW raised the voltage when they went to a factory AGM or is the mod still recommended?

The oilhead regulators were never changed to a higher voltage.

A very good mod to do, although tedious if the bike has ABS.

 

[globalrider]

Therefore, although it's a lot of work, raising the alternator voltage 0.7V with a diode as GS Addict, myself and others have done, get the charging voltage just right.

But are users getting 10 serviceable years out of them?

 

[globalrider]

I can't remember if the R1150GSA did. But yes, BMW tailored the VR voltage to the battery.

The VR on my 03 and 04 GSA was set for the factory GEL that it came with. High 13s low 14s.

 

[gsaddict]

The VR on my 03 and 04 GSA was set for the factory GEL that it came with. High 13s low 14s.

Same unit for all Oilheads (and K's of the same vintage) per MAX fiche.
http://www.maxbmwmotorcycles.com/fi...&searchtype=partnumber&parts=12 31 1 739 365

 

[Mr_Canoehead]

I have been reading up on this. Lots of confusion as to whether the BMW OEM is Gel or AGM. I still have the original in my garage, so I went out to take a look and it is an Exide Gel battery, not AGM.

 

[roger 04 rt]

But are users getting 10 serviceable years out of them [AGM batteries]?

Yes, one of my AGM batteries (manufactured by EnerSys, parent of Odyssey) is nearly 16 years old, is maintained at full charge and is still in service. As you know, the key to longevity is maintaining a battery at 100% SOC (state of charge).

Although most Oilhead owners seem very satisfied with the PC680, they would get even longer service and faster starting if the battery was maintained at 100% SOC with the right VR and/or maintenance charger.

My PC680 was mistreated by me for its first year but now, approaching 4 years, it has full aH capacity and is performing like new.

I have been reading up on this. Lots of confusion as to whether the BMW OEM is Gel or AGM. I still have the original in my garage, so I went out to take a look and it is an Exide Gel battery, not AGM.

The Oilhead OEM battery is not AGM. I have gone through the parts lists exhaustively but some models of R1200 are AGM. The key is to look at the charging voltage of the alternator, from that you can infer battery type.

 

[globalrider]

Same unit for all Oilheads (and K's of the same vintage) per MAX fiche.
http://www.maxbmwmotorcycles.com/fi...&searchtype=partnumber&parts=12 31 1 739 365

Any idea what the Bosch part number is for the voltage regulator?

 

[globalrider]

Yes, one of my AGM batteries (manufactured by EnerSys, parent of Odyssey) is nearly 16 years old, is maintained at full charge and is still in service. As you know, the key to longevity is maintaining a battery at 100% SOC (state of charge).

Its why my flooded lead acid batteries lasted that long or longer as well. The charging system in the car was spot on and I was able to "maintain" my FLA batteries periodically. And neither of them needed a battery maintainer since they were daily drivers (well mom's wasn't).

By the way, if a VRLA battery gases, how do you replenish them?

 

[jsouth]

VR with higher charging voltage

Any idea what the Bosch part number is for the voltage regulator?

Has anyone tried this?

http://www.euromotoelectrics.com/BOSCH-Voltage-Regulator-BMW-R-K-12-31-1-739-365-p/boalt-reg365.htm

Looks to be a quick solution -- 14.5V output and drop-in replacement. Not too pricey, either.

 

[gsaddict]

Has anyone tried this?

http://www.euromotoelectrics.com/BOSCH-Voltage-Regulator-BMW-R-K-12-31-1-739-365-p/boalt-reg365.htm

Looks to be a quick solution -- 14.5V output and drop-in replacement. Not too pricey, either.

Should work fine, but ultimately I would prefer the diode mod as it sits a bit higher at 14.6-7. Also less $$

That was not available in the past, Roger and I did a lot of digging.

 

[globalrider]

Has anyone tried this?

http://www.euromotoelectrics.com/BOSCH-Voltage-Regulator-BMW-R-K-12-31-1-739-365-p/boalt-reg365.htm

Looks to be a quick solution -- 14.5V output and drop-in replacement. Not too pricey, either.

I came across it when I Googled the BMW part number.

I was hoping to get the part number and specs on the BMW part. All I got was a slip ring diameter of 14 mm which is small compared to all those on my VR list (usually between 28 and 32 mm on car alternators). I was looking for a VR with a different V-set.

By the way, is it a Bosch or Valeo alternator? BMW has switched to the latter years ago in their cars.

 

[gsaddict]

Any idea what the Bosch part number is for the voltage regulator?

.

 

[globalrider]

.

Great, thanks!

Wow, lots of corrosion on that alternator casting.
So it is a Bosch unit.

V-set appears to be 14.1V for that unit due to the GEL installed.
Also seems to be used in the 3 series of BMWs.

 

[gsaddict]

Great, thanks!

Wow, lots of corrosion on that alternator casting.
So it is a Bosch unit.

Came out of a wreck that was left outside uncovered.

 

[jsouth]

Should work fine, but ultimately I would prefer the diode mod as it sits a bit higher at 14.6-7. Also less $$

I have not been able to find the diode mod anywhere. Do you have a link or better yet a schematic?

 

[gsaddict]

I have not been able to find the diode mod anywhere. Do you have a link or better yet a schematic?

Roger 04RT ended up documenting it in the end. I don't have a link but its here somewhere.

 

[roger 04 rt]

Alternator mod: http://forums.bmwmoa.org/showthread...y-2004-R1150RT&p=907139&viewfull=1#post907139

 

[gsaddict]

Thanks Roger!
This time I'll bookmark.