Charging Battery - 1200 GS 08

[Kahuna]

Got home this weekend to discover a completely flat battery - no surprise I have to say!

Anyroadup - I have my Optimate flying leads attached to the battery terminals and so I just connected up my Optimate SP and expected a test then a charging cycle.

Problem is - after 3 hours of connection the SP is still in the test cycle so it says! Is this normal for a completely flat battery?

I tried the disconnect and reconnect routine (which has worked on other bikes in the past) to no avail. Could I have wrecked the battery by leaving it discharged for 2 months (been overseas)?

Feedback appreciated.

 

[harry]

I'd keep the OM on for a couple of days just on the off-chance it will do the trick

 

[AdamA]

I would try another charger.
Optimates have a habit of being crap.
I had two at one stage and one often told me batteries were US when the other thought they were fine. After a while they both told me it (I have a decent battery tester at work) so I binned them and use something better.

I know a lot of people who won't touch optimates.

 

[Kahuna]

I would try another charger.
Optimates have a habit of being crap.
I had two at one stage and one often told me batteries were US when the other thought they were fine. After a while they both told me it (I have a decent battery tester at work) so I binned them and use something better.

I know a lot of people who won't touch optimates.

What do you use now AdamA?

 

[AdamA]

What do you use now AdamA?

You can't afford it.
(Guess I know, but it is designed to charge military aircraft batteries).


The trouble is with optimates and the like is they are "intelligent" chargers.
Only takes the sensing circuitry to be slightly off and the whole system is effectively useless.
Just try a simple trickle charger. Slower the better.

 

[Fanum]

I'd be straight down the dealers asking for another battery meself

 

[Kahuna]

Thanks Fanum - that may well be the next step after this...

Right - next instalment

Battery is charged - or at least its taking no more charge. I tried it with three different chargers so I know it's taking no more juice.

Tried to start up and the starter relay just clicks like there is not enough power to turn it over.

Re-charged and re-tested for charge rate - same click and nothing.

Managed to get hold of a GS911 tester and the bike had a couple of fault codes for under charged battery, though its currently sitting at 12.93 v.

Cleared the fault codes and tried again with the same results.

Anyone know the minimum charge level for the bike to turn the starter? I think it should charge from the alternator at 14.3v but should start the bike at 12 I thought.

Feedback appreciated!

 

[IainMac]

Sounds like your heading down the path of needing a new battery. Had a similar problem on missus old MPi Mini. Charged "ok" and had the right voltage but couldnt supply enough current to spin the starter, the battery in question was less than 3 yrs old but had been subject to long periods on inactivity.

 

[Deleted account 210609001]

Sounds like your heading down the path of needing a new battery. Had a similar problem on missus old MPi Mini. Charged "ok" and had the right voltage but couldnt supply enough current to spin the starter, the battery in question was less than 3 yrs old but had been subject to long periods on inactivity.

Similar story with my OE 1200 battery. Could charge it until the cows came home, but by the end it wouldn't turn the engine over. Voltage was a tad under 13v, just like yours.

 

[AdamA]

The voltage of the battery means nowt.
It is the voltage of the battery when under cranking load you need to measure.
Basically measure the voltage whilst you press the starter for a few seconds.

The voltage shouldn't drop much under 9-10 volts.

If it does, new battery time.

 

[sigmaglider]

charging.

Hi Adam, you might be the man to ask. i dont use bike to much over winter, is there any harm to bike..ref.. computer& imoboliser if i take battery off to charge it.? i have no electric where i keep bike. Ivor.

 

[AdamA]

Hi Adam, you might be the man to ask. i dont use bike to much over winter, is there any harm to bike..ref.. computer& imoboliser if i take battery off to charge it.? i have no electric where i keep bike. Ivor.

No idea tbh chap.
Not sure how the software is stored.
I would guess it's stored on media that won't lose it with no power attached for a long time such as EPROM, but I don't know.
If that is the case it should be fine.

 

[sigmaglider]

Ok thanks for reply,p.s. i forgot to mention the model.1200 gs.07.

 

[wilbjr21]

Got home this weekend to discover a completely flat battery - no surprise I have to say!

Anyroadup - I have my Optimate flying leads attached to the battery terminals and so I just connected up my Optimate SP and expected a test then a charging cycle.

Problem is - after 3 hours of connection the SP is still in the test cycle so it says! Is this normal for a completely flat battery?

I tried the disconnect and reconnect routine (which has worked on other bikes in the past) to no avail. Could I have wrecked the battery by leaving it discharged for 2 months (been overseas)?

Feedback appreciated.

You don't say how long you left the bike.

If this was for an extended period of time then the battery will go flat and thus be irrreparably damaged. This will not be covered under warranty.

Good luck

 

[Kahuna]

You don't say how long you left the bike.

If this was for an extended period of time then the battery will go flat and thus be irrreparably damaged. This will not be covered under warranty.

Good luck

I mentioned 2 months but in fact it was 6 weeks - dont think a battery should be damaged in that time frame! Do You?

 

[MattW]

I mentioned 2 months but in fact it was 6 weeks - dont think a battery should be damaged in that time frame! Do You?

Unfortunately, once you've dropped a lead acid battery (whatever its type) below 50% capacity, you've irrevocably damaged it. Once you've flattened it, it's effectively toast. It may appear to charge and show good voltage, but it's charge capacity has been ruined, so under load (i.e starting), it can't deliver enough current. In this respect AGM batteries are actually much worse than standard wet lead acid batteries - the only advantage of AGM / gel batteries is that the won't leak if you drop your bike - in every other respect they are worse than standard 'wet' lead acid cells.

There is a load of cr*p / snake oil about with regards to batteries and chargers (especially optimates), but the simple fact is that there's no way to 'rescue' a flattened battery. The only way to get decent life out a battery is to not let it flatten in the first place. Lead acid cells always self discharge and if running alarms etc, it doesn't take long to drop them below 50% or indeed flatten them completely. I use one of these:
http://www.sterling-power.com/products-chargers-probudget.htm
It's a proper constant current, 4 stage charger / power supply (left over from when I used to have a camper van).

cheers
M

 

[Kahuna]

Just called BMW Assist (after talking with the dealer) and they'll be here with a new battery soon so they say!

 

[Kahuna]

BMW Tech guy has been and replaced the battery. All's well and he's advised me to have the Optimate plugged in at all times when not riding (in the garage obviously )

The old battery was reading 'Good Battery' on his diag tool, but it was obviously goose'd !

Well done BMW Assist.

 

[Parky]

Hi Adam, you might be the man to ask. i dont use bike to much over winter, is there any harm to bike..ref.. computer& imoboliser if i take battery off to charge it.? i have no electric where i keep bike. Ivor.

I've done it before. The only thing it will do is reset the clock and the two trip mileage counters.

Don't forget to reset the throttle by opening and closing it fully a couple of times after you reconnect the battery. Full instructions on how to do this are in the manual, it's easy, I just can't remember if you have to do this first time without starting it up.

 

[wilbjr21]

I mentioned 2 months but in fact it was 6 weeks - dont think a battery should be damaged in that time frame! Do You?

You've been a lucky boy getting a new battery under warranty.

If you have a look at your handbook it will state that you need to charge the battery if it is to be left for more than four weeks - either on the bike (using a suitable charger) or off the bike.