Just taken receipt of new (to me) 2011 1200GS. Handbook says don't charge battery directly by connecting to terminals as it upsets the electronics. Does it really? I charge my 2014 Tiger that way with no ill effects. It's a pukker Optimate job that stays connected to other bikes for weeks on end without harm. Is there something peculiar about the GS that means I shouldn't? Thanks folks.
Charging battery directly to terminals - aye or nae?
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JimmyMac
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I have a 2010 GSA and the Optimate leads are connected straight to the battery, no issues and still on original battery after 8 years.
I plug it in after most rides.
Cheers
JimmyMac
I plug it in after most rides.
Cheers
JimmyMac
Long ago you could damage a Lucas ACR if you didn’t disconnect the battery. I used to unplug the plug form the back of the altanoter if I could get my hands on it. Although the advice is often repeated I’ve haven’t seen damage caused by this in a very long time. Of course the cynical might ask how do you know? Why are you charging the battery anyway? JJH
I suppose they have to advise that so as to cover themselves against someone banging any rough old charger onto the battery.
If you have a modern, made for the job charger, it'll be fine.
If you have a modern, made for the job charger, it'll be fine.
Bendy toy
Registered user
I always charged mine direct to the battery. Even BMW’s own charger effectively does the same though it connects via a canbus controlled power socket.
If your battery is getting tired replace it with a JMT lithium. The 4AH is 1/2 the price of an Odyssey but more than a basic lead acid.
A lithium at 4AH has the same engine cranking duration as a 14AH lead acid.
If your battery is getting tired replace it with a JMT lithium. The 4AH is 1/2 the price of an Odyssey but more than a basic lead acid.
A lithium at 4AH has the same engine cranking duration as a 14AH lead acid.
Deleted account 191119001
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Optimate 4 on mine and SAE lead, only use it in the freezing cold winter if bike is not used for more than a month, but no problems at all, I done this with every bike I owned.
Bendy toy
Registered user
Another thought.
Maybe the advice is given because Optimates will deliver a “high” voltage charge when battery is very low. When battery is good it uses normal voltage.
This (about the canbus version) https://www.optimate.co.uk/products/optimate-4 says the 22V recovery mode is only given when electronics are not detected.
So it’s possible an older Optimate model just might fry the canbus. But in reality it should be more than capable of taking 22V. Bike electronics are built to handle much higher voltage spikes.
That said, a dead flat battery should always be disconnected to give the charger the best chance of recovering it.
Maybe the advice is given because Optimates will deliver a “high” voltage charge when battery is very low. When battery is good it uses normal voltage.
This (about the canbus version) https://www.optimate.co.uk/products/optimate-4 says the 22V recovery mode is only given when electronics are not detected.
So it’s possible an older Optimate model just might fry the canbus. But in reality it should be more than capable of taking 22V. Bike electronics are built to handle much higher voltage spikes.
That said, a dead flat battery should always be disconnected to give the charger the best chance of recovering it.
Might seem thick, but ... where else are you going to connect to...
If the battery is off the bike, I connect direct to the battery ..
On the bike, it's either direct to the battery, or to an optimate lead.....which is connected direct to the battery
Only time ive seen it done not to battery, is where the batter is covered or innacessabe
then there is a defined +VE & -VE set of terminals to connect to
If the battery is off the bike, I connect direct to the battery ..
On the bike, it's either direct to the battery, or to an optimate lead.....which is connected direct to the battery
Only time ive seen it done not to battery, is where the batter is covered or innacessabe
then there is a defined +VE & -VE set of terminals to connect to
Ah. I consider myself well and truly put in my place.
Bendy toy
Registered user
You vill only use ze BuMW stamped charger. You vil know is top qualitat because it costs 3x more zan ze von our Chinese suppliers ripped off.
Ve tvy not to mention zat ve Germans are great at metal bashing but ve suck at eletvonices. Can't be too careful.
Bendy toy
Registered user
It’s a BMW so you are expected to change the battery before every “riding season”.
As already said Lithium solves the problem.
How so, the same circuits on the bike are still going to be in the charging path no matter what type of battery is installed?
My assumption is that when charging to the battery terminals directly, all permanently connected circuitry gets 12V + the extra supplied by the charger and the charging current supplied by the charger (which varies depending on the level of charge the battery has). So the circuitry gets more 'power' than normal, possibly more than it can be guaranteed to cope with. My further assumption is that when charging via the power socket, there is some protection electronics that limits the voltage and current that makes it into the rest of the bike, so to speak. Hence, charging via the power socket is 'safer' as some level of protection from over-voltage and over-current is afforded. I should say I am not an electrical engineer, I am an environmental scientist, who is likely to be buying an Optimate 4 with BMW CANBUS support very soon...
When the engine is running the alternator charges the battery at around 14.5 volts and at whatever current is being drawn by the battery
determined by it's state of charge at that time. A quality charger will only deliver similar and as far as the electronics not being able to take the voltage
this will not be the case as they are designed for it and more. My old Optimate has worked fine over many years and 3 GS's without "blowing" a thing.
The battery needs an input of around 13.5 volts to overcome internal resistance before it will charge any circuits connected will only draw current they require to work hence the charging current level would no affect them.The only assumption I can draw is the bikes electronics are so poorly designed to cope with anything over 14.4 volts [the output from the stator] that the sentence is a catch all for chargers who have little control over voltage output.
So how does the manual suggest the battery be charged should it be needed?
So how does the manual suggest the battery be charged should it be needed?
Yep, post 4.
The manual says the battery must be disconnected, unless of course, surprise surprise, you have one of their "specially designed" float chargers
Bendy toy
Registered user
BMW are in the market to sell expensive accessories so any excuse to make maintenance look complicated and push their “canbus safe” charger.
I don’t have mains power to the garage so just fitted a battery that doesn’t need to be mollycoddled.
