Voltage Across Battery Terminals...

How old is your battery ? Older bit still fit for purpose , may show only 13v~ my lithium battery only shows 13•7v and bike alternator and regulator are fine.

 

what year is the bike Steve? if a 955I of 02-04 vintage it could be the old wiring harness problem. have a look at your fuse box for signs of over heating on the charging circuit fuse., that would be a worse case scenario. I know the Daytona suffered but not sure about the SP model

 

It would be!

The voltage you are reading is the output from the regulator/rectifier moderated alternator. It is not too shabby...... some give a little more but a fully charged battery is 12.7v so it is getting topped up.

 

ignore my post then mate, I think the issue was sorted by then

 

Most generators on bikes will output up to 14.5 v at max, there should be figures for voltage at a range of revs in a workshop manual. or tellus the model and someone will chime in with the values but at 4k I would expect nearer 14v but proof of pudding is does the battery start the bike ok?

 

Could be the way Lithim batteries deliver current, it has lower crank amps but can deliver a higher percentage on demand and for longer.
So lithium manufacturers have a calc they do to show their cold crank amps as higher and some overegg the figure?
I have put a Lithium in my T120 nd it starts it fine which is good going for a big twin.
What make of Lithium did you get? Mine was a JMT

Did you ever charge the Lithiums?
other peculiarity is they need woke up apparently so second stab should be stronger!!

 

Lithium batteries really REALLY hate the cold
Mine can drop 0.5 volts over night if chilly.

So in leave the lights on which activates/wakes up the battery and after trying to start a couple of times it will start up.

One upgrade I did (thicker wires) is to the wire from battery to solenoid to starter motor, and from stator to rectifier and then direct to battery (not through ECU) and the charge is higher 14.3v, the starter is stronger, all with less stress in the stator

Edited 16th 14:00

 

I've had two lithium batteries and neither would start the bike on
cold days. Now I use lead/acid over winter.

 

Battery voltage depends on several things. One: The level of charge. Is it fully charged ? Or maybe down a bit. Two: The cutout voltage of the regulator This is part of it's built in specification. It varies a bit from one mfg. to another. Three: In a lead/acid battery what is the specific gravity of the battery acid. The higher the specific gravity, the higher voltage is possible [only to a point]. Low specific gravity [too much water] and the battery is not able to achieve a higher voltage reading, even if the charging system is capable of more, when the system shuts down, the voltage will settle at what ever point the specific gravity of the solution will allow. ...J.D.

 

Have a look on the Electrix website they have a good flow chart to help you isolate what is your problem. They also do a heavy duty rectifier/regulater