BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

Hi all,

I let my bike sit for a while and the battery died. I managed to charge it up enough to get it running again. I have two questions for you all. Will the alternator generate enough power to recharge the battery? The bike no longer starts in gear with the clutch pulled in and kickstand up. Is that a symptom of a low battery?

Thanks.

2 lines of a question... but a full page of answers to be truthful

The battery recovery depends on the age of the battery, old batteries have trouble coming back to a serviceable state.
if let go for too long.

If the battery voltage goes to a certain threshold the alternator wont bring it back if its too low

Boxers are hard to turn over cold even with a new battery.

The symptoms can also be related to the alternator , the alternator regulator, or the battery as they all effect one another
harmoniously, but you can usually start with the battery first.

What is an acceptalbe voltage range for the battery? I guess I will check that first and go from there. Thanks for the response.

Batteries have 6, 2 volt cells if the battery reads 10 volts or less you have a internal shorted cell
and no amount of charging will remedy, in the old lead acid batteries (assuming you have a gel battery)
you could use a hydrometer to determine the specific gravity of the cell.

You might want to consider a battery tender it will keep the battery at a constant state of charge. The nice thing about the tender is it will not over charge the battery. I have all my bikes plugged in to battery tenders and all are ready to ride any time of year.

+1 both bikes plus I use BT's on both the cars too .
Never had a battery issue issue and I just replaced the original 6yo battery in my RT, which was still in good (but not great) shape and also my BMW cage, 6 years and still in good shape.

roadglide wrote:You might want to consider a battery tender it will keep the battery at a constant state of charge. The nice thing about the tender is it will not over charge the battery. I have all my bikes plugged in to battery tenders and all are ready to ride any time of year.

philbytx wrote:+1 both bikes plus I use BT's on both the cars too .
Never had a battery issue issue and I just replaced the original 6yo battery in my RT, which was still in good (but not great) shape and also my BMW cage, 6 years and still in good shape.

roadglide wrote:You might want to consider a battery tender it will keep the battery at a constant state of charge. The nice thing about the tender is it will not over charge the battery. I have all my bikes plugged in to battery tenders and all are ready to ride any time of year.

A good idea is to disconnect the minus connector from the battery if the bike sits idle for some time (especially in cold conditions). Because even a small consumer like the clock can kill a battery in a few months ...

Kind regards
Oliver

Once a battery is cranked (by trying to start the bike) down to zero power, in the cold, does putting it on the battery tender repair it as if it hadnt been run down to zero, or does running it all the way down do permanent harm?

It's never a good idea to run a battery completely flat because once the volatage gets below 11 Volts or so, they don't always come back to full charge.

Put the battery tender on the bike & let it sit charging for a day until the tender cycles off. Disconnect the charger, turn the ignition on, headlight on and let it sit for 15 or 20 seconds in this fashion. Turn the headlight & ignition off and check the battery voltage with a volt meter. Your reading should be around 12.5 volts or so and steady. If the battery reading keeps going down, the battery is not fully recovered. Put it back on the charger. What your looking for is a steady reading above 12.5 or so, which would indicate a good battery.

You should never try & charge a dead battery with the bikes alternator. It is extremely hard on the alternator. A battery always should be fully charged before you put it into service.