Modern Vespa

this battery i am testing is a 12.4v and the reading is 10.2 volts. it is not letting the scooter kick over but it is enough power to start the fuel pump. this is a china bike and i am wondering if this dip means the battery is done. with a charger on the battery we can get it to start but it wont if it sits. also anyone know of a place to get chineese scooter parts? thanks for your input. i am helping out a friend and i am not used to the china bikes. thanks

Good battery should put out 12 volts without motor running and 14 + volts when it is running.

The battery is dead. Take it out and go to Wal*Mart or your local battery shop, they can match it up.

orange s150,

Just FYI:

http://www.marxrv.com/12volt/12volt.htm

...scroll down a bit to the green/red/yellow battery State of Charge chart. 10.2 volts is off the chart.

So 10.2v certainly means the battery is VERY dead, but it would need to be charged up (IF it will take a charge, that is -- if not, it's gone) and then tested with a specified power drain for x-number of seconds to see if the battery voltage stays above (or not) a certain voltage BEFORE you throw it out (dispose of/recycle it properly, please). Any auto store should be able to check your battery as most have battery testing equipment (usually for cars but 12v is 12v).

If it's dead because it got too low too often and became sulfated, there are some "desulphators" on the market that may bring it back to life. Google for them.

If a known GOOD battery keeps discharging too soon, then the charging system is not keeping it charged properly or, something (like an alarm or short) is draining the battery while parked, or it's being started often but not driven long enough to keep it charged.

As for China scooters, it doesn't matter: Batteries are batteries, and 12v negative ground batteries and charging systems are all pretty much identical, with the same basics in common whether it be no-name Chinese or Vespa, a car or motorcycle. 12v DC basics/laws are the same.

If you need to get a NEW battery, get an AGM (Absorbent Glass Mat) no-maintenance 'dry' type battery rather than those old types you have to keep the electrolyte levels checked and topped-off, i.e., 'wet' batteries. The AGM batteries are great...I won't ever buy a 'wet' battery again...there's no need to anymore; IMO they're obsolete. If your friend's scooter CAME with a 'wet' battery, upgrade to an AGM the next time you buy a new battery....just look for one with the same or greater Amp-hours (Ah) rating AND, of course, one that physically will fit in the scooter's battery compartment.

Sorry...can't help you with a source of Chinese scooter parts...I didn't get one of those myself partly because of that issue.

Good luck...

thanks. i figured the battery is dead, but it is my neighbors bike, so i am not fimmlar with how it was maitaned. yesterday i learned the problem and it made sence that it was the battery. thanks for all the advice. easy fix!

Last week I got a new battery since my last one already gave up (new gts 300 2023) at only 3 weeks old.

When riding 14.4
When bike just turned off 12.4
This morning when I started it 9.4
I rode yesterday. It is parked at a garage. Temp 18 celcius.

Today after a workday I'll check out what its status is after being outside in a parking for 5 hours.

Is the 9.4 a normal idle voltage after only 1 day? Or should I contact the service guys once again?

that is not normal. there is a fault somewhere, contact the service department.

also, in the future try and refrain from dredging up a post from 13 years ago. there are more current topics that you can use to comment on or start a new one.

Thank you. I find it hard to choose between starting a new one or first use the search to see if simular posts already exist. Some forums choose the latter. Will start a new one here next time.

All the numbers are OK, except that 9,4 after one night. That still should be close to 12,4.

It means something drains your battery, consumes electricity, something that does not shut down properly, when you switch off the scooter.

Most probably you have that problem since the beginning what explains why you needed a new battery after 3 weeks. 3 weeks is a ridiculous lifespan for a battery.

Go to that service center

12.4 volts was already not super. For perspective:




Remember that if you check right after a ride the voltage will be high. You need to measure after the bike's been sitting for a while. How long? Dunno. I'm not a tech. Maybe an hour to be safe.

PS: This is the chart for lithium batteries, just for awareness:

Very helpful charts. Thanks!