T350 charge voltage when running

[joethebike]

Been having some issues with my 350 so checked all connections on the charging circuit and plugged the green wire into the red/green to make the lighting coil come on all the time.
When checking the battery voltage at about 4000rpm I was surprised to see battery voltage was at 16v with no load apart from the ignition.
I know there is no voltage regulator on my bike but the battery voltage was surprising. It's a pity I did not measure voltage before making the change.
My battery is 6 years old and holds about 12.2v after a couple of weeks sitting so if that is the sort of voltage it receives when running it has not caused battery problems.
My headlight runs an H4 halogen bulb 50/45 watt and with the new charging setup battery voltage holds at about 12.5 volts with the lights on low beam at 4000rpm.

Is the 16volts with no load likely to cause battery boiling?

[jabcb]

Your mod is described in this service bulletin: http://www.ozebook.com/compendium/techb ... mpress.pdf
It increases alternator output when the lights are off but doesn’t affect the output when lights are on.

Back in the 70s, it was considered OK for voltages to get up to 16V.
Conventional batteries that you add water to will tolerate it, but you’ll have to add water more frequently.

That voltage is too high for modern AGM & maintenance free batteries.

The T350 spec was for the battery to start charging by 2k rpm.
12.5V @ 4k rpm is low, but then your headlight uses a good bit more amps than stock.

It may work out OK for you depending on how much ride with the lights off & lights on.

You may find a battery tender/maintainer to help. They sell quick connect wires so you won't have to remove the side cover to connect the tender/maintainer.


Some T250/T350/GT250s are picky about the battery having a good charge & won’t run well with a weak battery. Others aren’t so picky.

My 71 T350 isn’t very picky. I disconnected the battery when adjusting the points. Was interrupted & neglected to reconnect the battery. It started easily & ran fine — everything was good till all the lights burned out.
My GT250 was the opposite. You could tell the battery wasn’t charged by how well it ran.

[rngdng]

I would keep the lights on.....


Lane