Pointy Charging Issue

[glade]

Over the years I've gone through batteries like no-one's business when not using the bike for any length of time.

Now I have year old battery that totally discharged over the winter.
Brought it back using CTEK charger/conditioner, and was OK for a few months.

Have been using bike fairly regularly... maybe once or twice a week, with periods of 2 or 3 weeks off.

Went out one morning after a short break and battery dead.
Bumped the bike a few days in a row hoping the run to work would bring it back, no joy.

Charged again on charger, but after a couple of days dead again.

So... I want to fix root cause of battery issues, before I buy my 4th or 5th battery in 8 years, and kill that too!!!

At idle the battery voltage is about 12.9V
With some revs it tops out at 14.26v

Diode check on rectifier... all diodes working, forward voltage drop about 0.58v using a (calibrated) Fluke Multimeter.

Checked stator resistance, but can't do voltage when running because bike in bits now with dead battery.
0.4 ohm each way.

Is that idle voltage of <13 an indicator that the reg/rec is done?
There is a slight swelling on the potting on the back of the reg/rec - not sure if this is significant, I guess they get hot in normal use.

I'd rather not strip alarm out if I don't have to - I measured current drain, from battery -ve to earth (though the alarm was "deactivated") ~35mA.

[Craig380]

That 35mA drain isn't huge but over a week or two it will drag the battery voltage low. The voltages with the engine running seem OK, it should be around 13V at idle and over 14V at around 4000-5000rpm.

Do you keep the battery connected to the conditioner all the time when the bike isn't being used? You might need to, to offset the current draw on the battery from the alarm.

[glade]

Sadly I moved somewhere with no electricity in the garage.

Though my boss says I could wire up my charger out the back of the factory and leave it on charge during the day... Which could well be the answer.

[maviczap]

Sadly I moved somewhere with no electricity in the garage.

Though my boss says I could wire up my charger out the back of the factory and leave it on charge during the day... Which could well be the answer.

If you're not using it for 2 or 3 weekks sometimes, thats what's killing the battery.

As you have no electricity in the garage, then take the battery out and put it on the optimizer in your house when you're not using the bike

[ophic]

I'd rather not strip alarm out if I don't have to - I measured current drain, from battery -ve to earth (though the alarm was "deactivated") ~35mA.
I've been through a lot of batteries as well. Eventually I removed my alarm and had no further problems. Best thing I ever did. The bike even fired up after being sat in a garage for 6 months over winter.