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EWS active - low battery R1200RTW


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This is a 2104 R1200RT done 16,000 miles had the bike for a little over a year. I ride the bike regularly but on this occasion it had not been run for a week.


This morning I went to start the bike and got the "key" symbol which, looking in the manual, means "EWS Active" - the key is not authorized. (or communication between the key and electronics has a problem)


No other indications of trouble (low voltage warnings of which there at least 2) however...


The battery voltage was down to 9.1v so I put the battery on charge - after an hour or so the bike started. Everything had been re-set to defaults.


No biggie I guess but some misleading information?


I have noticed right from the get go that the reported battery voltage with the engine stopped seems lower than I would have thought (typ 10.5 > 11.0), it rises to 14.0 running but quickly decays back to around 11.5v after a short time with the engine stopped.


Anybody else have any thoughts? I am now wondering if the battery needs replacing.



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Unless you have some kind of parasitic current draw, then yes..looks like your battery is toast.

Easy to check

Pull battery

Re-charge on a reasonable charger.

Check it's voltage after charging and just after disconnecting charger

Check next day

If the battery completely disconnected from everything has dropped to 12Vdc or less....it's toast.


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FYI, the battery on my 2014 R1200RT died 14 months from new, always kept on BMW battery tender when garaged. The dealer's replacement battery would not hold charge in his shop so he found another for me which is OK 7 months later. If other 2014 R1200RT batteries are dying young there might be a quality control issue.

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So I did a bit of research on this, turns out that its quite hard to fully charge a battery and unless it is fully charged its performance deteriorates over time. The float charge is the solution 13.4v @ 1A maximum for a AGM battery. I am lucky enough to posses a lab power supply that allowed me to set a constant voltage of 13.4v with the 1A current limit. After about 24hrs the current had fallen to 500mA and after another 12hrs the current was down to few tens of milliamps. Disconnect the battery and 48hrs later the voltage is still 12.5v...

Watch this space...


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Afternoon hefy

I would be really suspicious about the charging of the alternator.

You have got the same model year as mine. Yours is without a doubt still under warranty. As far as I am aware, the battery has got a lot shorter warranty then the rest of the bike, but more important is that if the alternator is having issues then it is killing your battery.

Worse, the alternator would be a costly repair as it sits on the top of the engine and is integrated. So better to have it fixed under warranty.


As an example, my bike is happy to sit for up to 4 weeks and will still start without hesitation or any symptom of a low charge battery.

But we are in a very temperate climate over here.


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You could be right Terry, although it's really on the edge of good/no good.

Just consider that theses are quite small batteries compared to your average car battery with a lot higher Ah capacity. Wet-cells do have an inherent higher self discharge. So I would leave it for another 24hours, if it still drops, then the battery is basically toast.

In the end, the only true test is to do a "load test".

Take it around to a battery place and get them to test it under load.


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