Modern Vespa

Hi,

We recently purchased a used scooter (2007 with 2,700 miles) and the battery discharges after the scoocter is ridden for approximatley 60 to 90 minutes.

I replaced the battery with a FULL charge and the same situation occurs.

Jerryw had a good discussion on the "hidden fuse" for an MP3 500 but the set up appears to be different on the 250.

Any ideas or suggestions?

Could be a bad voltage regulator or alternator. I am waiting for a new voltage regulator but my symptoms are opposite of yours. It was overcharging. Good luck.

Check all the wires on the battery and voltage regulator to make sure they are not damaged or disconnected. MP3 250: Removal of the voltage regulator

Added: (You may want to try this first) If you have a multimeter connect it to the battery terminals and start the motor. You should see the voltage jump up to around 14v especially if you give it a little gas. Be careful giving throttle on the center stand...good idea to hold the front brake to keep your scooter from moving.

I tested the battery and it's charging at 12.6V at 3K to 4K RPM with some minor fluctuations (0.2V + or -).

My only thought is to ride it and test the battery every 15 minutes or so (I have permanently connected the leads to the battery terminals).

Any thoughts?

Thanks for all of your help!

I don't understand the permantley connecting the leads part. take a pic please and post. As far as the battery not holding a charge it is a 2007 and could be just junk by now. (3 years old) I would just get a new battery, fill it properly, charge it properly (no more than 2 amp charger) and then install.

OK,

First, thanks for the input from everyone; I appreciate it.

I took the scooter out with the voltmeter connected to the battery. For the first 10 minutes or so the charge was ~14.0V and then slowly declined to the point where, after 5 or 6 miles, the charge went all the way down to ~11.0V.

I let the scooter sit for a few hours, with a 2.0Amp charge on it, brought the battery back to 12.6V and started it up. The charge was again in the ~14.3V range at idle and DECREASES to a 13.0V or less range between 3K and 5K RPM.

My uneducated guess is that the voltage regulator is malfunctioning. BTW, it is a brand new battery that was properly charged to full capacity.

That's weird. A voltage reg usually either works or it doesn't. 14v sounds right for the charge voltage. Dropping voltage as the bike runs implies that the capacity is insufficient to both run the bike and charge the battery. Diminished output can be caused by a bad ground or other electrical connection. Think a trickle from the faucet vs opening ti wide. I would first check the battery connections and the ground. You obviously know how to use a meter so check resistance to ground. Then check the plug on the VR - clean and apply dielectric grease. Finally - check the hidden fuse.

OK, great. Where is the "hidden fuse" on the MP3 250? It is different than the 500. Thanks!

I am thinking that at 4000rpm the charging voltage should be just over 14v. It could be the hidden fuse but I am ashamed to say I have not ever looked for it on my 250. I will take a look tonight.

No hidden fuse on the 250 - the voltage reg protection fuse is fuse#1 - 30A - in the battery compartment.

So either you have an abnormal current drain as the revs increase, or a weak stator (perhaps even windings breaking down as the AC volts rise with revs) or a strangely duff regulator.

Thanks for saving me the time looking Jim. And I agree with what you said and yes it would be an odd VR problem from what I have read.

sounds like the VR is performing fine, I still suspect the battery as a bad cell will cause a drop. What kind of battery did you install and which battery model number? Did you do the initial fill or did the place you bought it from do it, and who did the initial charge on it and at what voltage and for how long?

hi all any news on this i have the exact same issue new regulator and new battery's x2 new spark plug new solenoid my battery just drains and at around 20miles its dead and cant start the bike if i fit a new battery it fires right up and works