new Battery only charges to 12.85 V

[resovoir]

More battery woes. Om my 2023 GS Rallye I have replaced the original battery Only 14 months old but out of warranty .
The old battery has always been on BMW battery charger and charged to 14.4 v. Just fitted a new Yuasa YTX14H-BS and the BMW charger only charges to 12.85V. Has anyone any ideas why. I have been reading the battery needs registering on the bike software, Is this correct.
many thanks for all comments received.

 

[er-minio]

AGM battery?

 

[Barnoe]

I might be wrong but don't batteries only register 14+ when they are being charged.

but actual charge held is around 12.8
I don't think I've ever seen any of my bike batteries show 14 when bikes off

An expert will be along soon hopefully.

 

[Paul G (BHT)]

I might be wrong but don't batteries only register 14+ when they are being charged.

but actual charge held is around 12.8

You’re not wrong.

 

[er-minio]

Not an expert at all but the resting voltage of an AGM battery should be around that voltage.
OP's battery should be ok.

 

[hawkeye]

First off, the battery does not need registering on the bike software.
I too have a Yuasa YTX14H-BS fitted to my R1250GS. I also have the BMW charger and also an Optimate 4 I use. At rest (no charge being applied) the battery sits around the 12.8v mark, on charge both chargers give 14.3/14.4v.

The difference between the two I notice is that the Optimate essentially charges in approx 30 minute cycles, with a break in-between, whereas using the BMW charger, the CanBUS seems to monitor the battery and only brings the charger "alive" when the voltage drops below about 12.75, taking it just back above this before going to sleep again. As a result, I find that using the Optimate, seems to charge the battery to a slightly higher level compared to the BMW one.

If you are using the BMW charger and its going to 12.85v before "going to sleep" then I'd say all is good. The only query I have is how old the new Yuasa battery is that you fitted; When I replaced mine the first one I had from Halfords had not been properly maintained (IMO), as it was virtually flat when I connected it up and when I checked it had been in their stock for some months; I took it back and got it replaced by one that was only a couple of months old, and had been maintained, and its been good the past 2.5 years whether connected to the BMW charger or the Optimate BMW charger.

 

[RadioFlyer]

The CAN-bus DOES NOT monitor the battery. That's the job of the ZFE. The CAN-bus provides a comms path between the various controllers.

 

[resovoir]

Thank you for all your help. I am happy all is working ok. I did check with BMW dealer and they said no need for software change, just fit new battery and off you go.