The workshop manual is available for download ( see wiki section of the forum). That says that if a good battery is allowed to discharge to 12 volts and the engine is then revved to 5000 rpm a current of greater than 20 amps should be possible. More importantly if you do not have an inductive type of ammeter the voltage under normal charging conditions should be around 14.5 volts. You do need to know that the battery is good because a bad battery can give all kinds of strange readings.
The normal charging voltage is ard 14.6v.there was a time i forgot to off the bike for like 5 hrs.the next day,she was able to start up just fine but the charging voltage while on the move was showing only 12 plus vollt.
After running for quite a while on the next day,the voltage was able to return to normal by the following day.
I purchased the Expensive Earth-X 36 Amp Battery.
Worked great for 2 winters, plenty power to spare when running heated gear even though the charging system could not keep up with the load.
The MP3/250 is terrible, the MP3/500 is much better but both lack the ability to support Pants, Jacket, Gloves that are heated... (I use Tourmaster.)
The battery would eventually recharge going at faster speeds.
Then when it died...
The Warranty, and adjustment of the price for replacement, it was just not worth it. I purchased 1 for each of my bikes, they all went out in 2 years or less.
For the past 2 years, I keep a standard Motobatt battery installed.
Then when I plan on using heated gear, I plug in a second Motobatt battery to double the amperage with a "Y Cable" I made. Works like a champ...
The Spare battery... only used in the Winter, comes in handy if your Primary Fails. Just install that one, buy another Motobatt...
So its a cheap way to go from 14 Amps to 28 Amps...
All Content Copyright 2005-2019 by Modern Vespa. All Rights Reserved.
Modern Vespa is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com.