Modern Vespa

My 2002 ET4 has always ended up with a dead battery after being inactivity for a week or two.
Well, not completely flat but not enough battery power to start the scoot.

Being curious if the battery was being drained, I hooked up a current meter to see actually what was going on.

I started the test with a freshly charged battery.

I measured the current flow out of the battery with the scooter turned off.
The measurements were the same regardless to the position of the kill switch.

I found the battery outputs a steady 2 to 3 ma (.002 to .003 amps) with peaks to
about 5 ma (.005 amps) synced with the flashing of the immobilizer LED.

I know that is a small current but if you average the total current flow I would guess
it represents about a steady state current drain of about 3 or 4 ma (.004 amps).

See video of meter reading:


So, 0.004 amps times 48 hours = .192 amp/hours which is only about 1/50 of the
Amp/Hour rating of the battery.
I am using the ES12-BS Wal-Mart Battery in my ET4 which is about 4 years old.
I doubt the 4 year old battery still has a 10 Amp/hour rating currently.
Click on (12-BS-Y.pdf) in the link below for battery specifications
http://www.staabbattery.com/product/Wal-Mart-Motorcycle-Battery/Wal-Mart-ES12BS-Battery.html

The immobilizer LED will quit flashing after about 48 hours if the scoot's ignition is not turned on.
See video of meter reading after the immobilizer LED quit flashing


So, theoretically it would take about 2,500 hours to totally drain the battery with a .004 amp current drain.
Of course, that doesn't take into consideration any internal battery self discharging currents.
I have read a flooded lead acid battery has a monthly discharge rate as high as 5 to 8% when the battery is new.

Of course, I always have the battery connected to a battery tender for long idle periods now.
Not sure if any of this explains anything except, I hate Scooter batteries and wish someone made a good one.

I think flooded lead acid Scooter batteries suffer from scooter vibrations.
I inspected the battery and found lots of sulfate paste particles on the bottom of the battery.
That probably accelerates internal discharging currents.

I am thinking my next scoot battery will be a AGM type.

Just come back from a couple of weeks running and MTBing in the alps to find and ET4 with a nearly dead flat battery which didn't turn the engine once, and a GTS which started on the P of Press.

Thanks for doing the reasearch for me on why.

Has anyone ever started an ET4 on the kickstart?
Surely they must have double jointed legs and really long arms.

From the posts I've read on here, the general opinion is, DO NOT kickstart an et4! Just what I've gathered, but I've never used it, despite having problems with my battery being crap, as I've heard quite a few instances of causing serious damage to the gearbox iirc.

Actually I don't think the vibrations harm them at all, but... It certainly does! A de-sulphating battery tender (Optimate or similar) can help, but that battery has had its life, time for a new one. They are less messy and do seem to last much longer - but still need keeping as near fully charged as possible for the longest life.

I am currently building a Lithium-Ion battery for my ET4.
Going to gut the old battery case and install the Lithium-ion into it.

Will be adding a breaker, temp sensor, ampmeter and charging regulator for this experiment.

The Lithium battery weight difference is unreal.
Thinking it may improve the ET4's ride by top side weight reduction.

I will keep the old battery terminal arrangement so I can switch back to a lead acid battery if the experiment doesn't work out.

I'll post pictures soon.