Is riding good for your battery.

[Chris Terry]

My 12 is 27 months old so I have replaced the (disposable?) battery. CW let me have it at 50% off as a "good will gesture". I'm not sure if CW or BMW cover the other 50% but anyway half price to me. As the bike is now out of warrantee I made some electrical checks to ensure the battery was charging ok.
1. Ingition on 12.87 volts at the battery terminals.
2. Bike running 14.4 volts max at any revs (after a couple seconds)
3. Bike running with everything switched on 14.4 volts max at any revs (after a couple seconds).
This looked good to me, but one thing occured to me is 14.4 volts on the battery all the time good for it?
I know that chargers vary voltages and currents to prevent over charging.

 

[Womble]

That sounds fine to me, and I wouldn't be worried about the charging circuit.

I'd be more worried about how long you aren't using the bike between rides. There are a few ways to drain the battery that will shorten the life, including sitting on the servo brakes at junctions, or idling with the headlamp on. Doing these just before laying the bike up, will leave the battery in a partially drained state. Having an alarm then servers to drain the battery even further.

If a battery isn't fully charged while stored, it loses overall capacity, getting worse over time. This is why people have a lot of success with Optimates etc. as the batteries stay fully charged.

You don't mention it in your post, but if I were you I'd consider a charger for use in the garage. As you've got a 1200, you will either need a BMW charger to work via the power socket, or a standard charger directly to the battery. If you haven't got a garage or power, then I guess that a solar powered doohickey from Maplin might help.

 

[NeverRodeBefore]

Don't get a small solar charger... I found mine was still down on voltage, so I got a bigger one mounted on the garage wall, the panel itself is about 12" square, and that one is very powerful

I know its possible to overcharge using conventional car chargers, but this panel is a so called smart charger so shouldn't do that, also it has a built in system to stop the panel drawing current out of the battery when it goes dark. Mine has been running on that panel long enough for me to know that it does its job.

 

[John Armstrong]

You don't mention it in your post, but if I were you I'd consider a charger for use in the garage. As you've got a 1200, you will either need a BMW charger to work via the power socket, or a standard charger directly to the battery. If you haven't got a garage or power, then I guess that a solar powered doohickey from Maplin might help.

You don't have to use the BM charger or one across the battery. I've used a £20 trickle charger on 2 1200 GS's with no problem

BTW if you use a solar charger it might be a good idea to have it in parallel with a 12v battery as the battery will keep the socket "live" if you haven't got the software which is on my 07 GSA that seems to allow a charger to charge the battery without the ignition on, charger on, ignition off cycle.

 

[Womble]

You don't have to use the BM charger or one across the battery. I've used a £20 trickle charger on 2 1200 GS's with no problem

I think there are a lot of people on here who will disagree. Your bikes, possibly as a result of your dealer's backup, haven't given you problems, but there are no end of posts about people having problems with charging 1200s. I was hoping that there would be enough information in my post to allow a sensible search, without hijacking the thread too badly from the original question.

BTW if you use a solar charger it might be a good idea to have it in parallel with a 12v battery as the battery will keep the socket "live" if you haven't got the software which is on my 07 GSA that seems to allow a charger to charge the battery without the ignition on, charger on, ignition off cycle.

Now that's a neat idea - nice one.

 

[Chris Terry]

My original point was that, with 14.4 volts across the battery during riding might be the reason the batteries die after 1-2 years.
Could it be that BMW have not got the correct charging voltage\amps ??

 

[John Armstrong]

http://www.sailgb.com/sshop/tech_info.asp?ID=223

http://www.baintech.com.au/html/ctek.html

http://www.baintech.com.au/CTEK_-_Product_Program_-_Screen.pdf

The above would say that 14.4 v is good.

 

[Chris Terry]

Tobermory Womble says...
There are a few ways to drain the battery that will shorten the life, including sitting on the servo brakes at junctions, or idling with the headlamp on. Doing these just before laying the bike up, will leave the battery in a partially drained state. Having an alarm then servers to drain the battery even further.
But....
With the engine running (even ticking over) the alternator is still charging the battery !.
In fact mine still has 13.8 volts across the battery with everthing on..both lights,heated grips, and servo brakes applied.

 

[davedyer]

Possibly without exception, all modern vehicle alternators put out 14.5volts across the battery when the engine's running.

The voltage is the 'pressure' that the electricity is being 'pumped' at - to use a garden hose analogy. In order for a 12v battery to take on more charge, the potential across its terminal has to be greater than 12v, otherwise it won't charge up. Why 14.5 volts? This 2.5v excess ensures that the battery charges at a reasonable rate - any less would then be a trickle charge and it wouldn't keep up with the demands from the vehicle - with headlights, heated grips etc running.

Can you over charge a vehicle battery? Yes, if the voltage is high enough to cause the battery to overheat and the electrolyte will boil and the plates buckle, touching each other and shorting out. But batteries are designed to run continually at 14.5v with no problems.

As for the life expectancy of batteries. My 9 years old Honda Pan European was on its originally battery when I sold it recently - and it started first time, every time. And it had heated grips!

 

[Bert]

get rid

of the more than useless original battery
Fit an Odyssey
charge up once properly
forget

and if riding in bright sunlight, I 'tell' my 1200 not to switch on the dipped beam either that puts a bit more juice to the battery.

 

[GPLongford]

Possibly without exception, all modern vehicle alternators put out 14.5volts across the battery when the engine's running.

Cars sold new here in Norway are ecuipped with alternators set to 14,8V - 15V. This is done to prevent dead batterys during winter.

On used cars imported from Germany / Denmark etc. battery problems are common due to alternators who put out only 13,5V - 13,8V

 

[Chris Terry]

of the more than useless original battery
Fit an Odyssey
charge up once properly
forget

and if riding in bright sunlight, I 'tell' my 1200 not to switch on the dipped beam either that puts a bit more juice to the battery.

You are wasting your time turning things off, your altenator has a voltage regulator and plenty of capacity to ensure your battery gets the same voltage to keep it charged no matter what you do.
Keep your lights on ...it might save your life.

 

[Chris Terry]

Possibly without exception, all modern vehicle alternators put out 14.5volts across the battery when the engine's running.

The voltage is the 'pressure' that the electricity is being 'pumped' at - to use a garden hose analogy. In order for a 12v battery to take on more charge, the potential across its terminal has to be greater than 12v, otherwise it won't charge up. Why 14.5 volts? This 2.5v excess ensures that the battery charges at a reasonable rate - any less would then be a trickle charge and it wouldn't keep up with the demands from the vehicle - with headlights, heated grips etc running.

Can you over charge a vehicle battery? Yes, if the voltage is high enough to cause the battery to overheat and the electrolyte will boil and the plates buckle, touching each other and shorting out. But batteries are designed to run continually at 14.5v with no problems.

As for the life expectancy of batteries. My 9 years old Honda Pan European was on its originally battery when I sold it recently - and it started first time, every time. And it had heated grips!

The maximum for a AGM battery is 14.4 volts and only then until it's fully charged. At that point the voltage should drop to 13.5-13.8 volts to maintain.

 

[Chris Terry]

I'm getting bored now... How about a word about AGM cells from our friends Exide\BMW ? to help us.