Optimate Query BMW F800gs

[Cone]

So I think I said before i've been having problems with flat batteries since I purchased my 15 plate F800gs. I thought this had been solved by my Optimate 4 I purchased.

However this morning in the rain i decided to ride to work and go across the small section of off road I have, wet slippy muddy and good fun.

Bike started fine (think it may have been connected to the optimate at the time) and I rode all the way up the muddy stoney track to a gate which is tricky to get through as only jsut wider than the handles.

So I stalled getting through, went to start and the battery was totally dead although it had been on the charger all the time.

So luckily i was at the top at this point and I gained enough speed to bump the bike started - which is tricky to say the least on a muddy track with a bike with that much compression.

The optimate is currently showing green on both indicators which means maintain, however I cant start the bike when the chargers unattached.

Any Ideas, no one else has these massive battery drain problems do they, I have no confidence no in this bike that it'll get me home when I need it too..

I new I should have brought a KTM or Honda!!!

[Richard Simpson]

Is the battery up to the job in terms of cranking power spec?

Is there a problem with the starter relay? On a 'normal' bike you can bridge the two big terminals with a screwdriver and see if the starter spins...I'd seek qualified advice before attempting this on the BM with its CANBus wiring though...

[Q plate]

Is the bike not under warranty still? I think from when you posted previously they do not suffer in general with drain issues. Apart from using the optimate Can you give some more info on what's been tried to rectify the issue. The battery could be defective, if you have access to a multimeter you could check/eliminate a drain on the system similarly all connections relating to battery/starter Need to be checked for tightness etc as they obviously draw a higher current

Regards AL

[Cone]

Yes I've emailed the dealer, but the manager is on leave. Im going to do everything through writing with them from now on as I have no confidence in them.

For such a reputable dealer (no names on here) as I could be being totally unreasonable. Sadly the dealer is unable to put my concerns to bed so their not shading them selves in glory at the moment with me.

How do I check the drain?

[fraserdog]

Sounds like duff battery to me,my old Africa Twin had the same symptoms,the battery was showing 12.5v static but when you hit the starter it dropped to 10v.

[Andi_Archer]

Have you checked the terminals on the battery and the starter are securely fastened?

[Whippet]

Don't know much about f800s, but do know about optimate's, silly question, but is the bike on canbus electrics? If so have you got the optimate set for canbus charging ?
Just a thought

[Oop North John]

That the charger thinks the battery is fully charged only shows that the charger thinks it's charged (thumbs)

I'd buy a new battery, charge it up and then see what happens. If it still goes flat quickly, then disconnect it after riding and then reconnect it.

One way of checking for a residual drain is to connect a 12v light filament (bulb) in series with the +ve lead.

[Cone]

Yes it has Canbus and I'm fairly certain all the connections are tight and the optimate is not connected to the can bus but directly to the battery using the supplied connector. I'll check the positive to and earth and look for any residual voltage. I would pressume the resistance will be too large for the voltmeter to read

[Oop North John]

Yes it has Canbus and I'm fairly certain all the connections are tight and the optimate is not connected to the can bus but directly to the battery using the supplied connector. I'll check the positive to and earth and look for any residual voltage. I would pressume the resistance will be too large for the voltmeter to read

Fairly certain = don't know IMHO.

It sounds like you need someone who knows their electrikery to help you (thumbs)