Generator output - is it enough ?

[Ossian]

My 955i Tiger is low mileage and all the wiring and connectors are in good condition. I have fitted the relay for both headlights to come on together , plus also a Shindengen SH775 series reg/rec and the Triumph link. As well I also fitted one of the early RHS switch units so the headlights may be turned off completely.
My problem is that on 3 separate occasions the bike has died . The circumstances where this happens are while riding with headlights on, in warm weather (in daylight traffic usually) and the engine fan has been running. After the first time, I fitted a voltmeter and found that while the reading was usually around 14+  volts , with everything running it slowly goes down to 11 point something and the engine stops. After stopping, turning the lights off, I can start again and continue with the reading back up to around 14. I thought I had a dud battery (a nearly new Motobatt) so changed it for a Bosch, but the problem recurred.
Does this mean that the generator is working OK but is just not capable of delivering enough current to run everything at the same time ?

[Timbox2]

Have you had a look at the Generator? If youve had reg/rec problems it may have burnt the Genny, pop the cover off and examine the coils. Beware the strong magnet pull, especially when putting the cover back, its best to have 2 or 3 long studs which can help guide it on straight.

[Ossian]

No, I have never had reg/rec problems. I still have the working OEM reg/rec and only changed that to a series type as a precaution. The bike shows a healthy charge normally and I'm wondering whether the combination of running with both headlights on when the fan cuts in is too much for the standard generator ?

[Timbox2]

No, I have never had reg/rec problems. I still have the working OEM reg/rec and only changed that to a series type as a precaution. The bike shows a healthy charge normally and I'm wondering whether the combination of running with both headlights on when the fan cuts in is too much for the standard generator ?

Well, i never had issues with either of my Girlies, both had the twin headlamp mod, heated grips and powered a heated jacket, never saw anything less than 13v odd apart from when I discovered one of the reg/reg multi plugs wasnt fully clipped in and it was dropping to the mid 12's.

[Chris Canning]

I've had some hassle with the charging system some of it self inflicted but twin lights and the fan on has never been a problem.

[Lee337]

I too have relays so both headlights work & even with in-town commuting, i.e. short runs with fan cutting in, I've not had an issue with Tiger cutting out.

The only time I've had something similar was on a Honda Blackbird (notorious for reg/rec & genny issues) & that turned out to be the genny. IIRC it was a small nick in one of the windings.

[HockleyBoy]

I had a problem with charging some time back which only showed up when the bike was very hot. If I tested it in the garage cold all was fine (around 14v), by the time I got to work through traffic the bike kept dying and was only charging at about 10v.

Took me a while to work it out 

In that case it was the RegRec that for some reason didn't function correctly when hot.

Worth testing yours even if fairly new.

[Ossian]

Hmm. Now that the colder weather is here, I'll have to try and get the bike up to temperature in the garage to see whether the symptoms can be replicated.

[Ossian]

Well, as an update, I ran the bike in the garage to see what would happen. After starting, the voltage went to 15+ and then settled to 14. I turned on main beams and brake light and set the bike to run at about 3ooo rpm. It took more than 20 minutes to get the bike really warm and gradually after about 30 minutes of running with the rad very hot and the fan working, the voltage slowly dropped to 11.8. When I turned the lights off and released the brake, the voltage went back to 13+. I let the bike cool down and restarted with the fan not running and the voltage went back up to mid 14s. So it would seem to me that the generator output is marginal. Hopefully this will only be an issue in hot weather with headlights on.

[HockleyBoy]

Those readings don't look too bad which is good so it is probably as you say just heavy load in hot weather.

[Timbox2]

Only thing I wouldnt be too happy about is the 15+V to start, sort of points to reg/rec maybe on the way??

[Ossian]

Only thing I wouldnt be too happy about is the 15+V to start, sort of points to reg/rec maybe on the way??

It's a series Shindengen SH775 with less than 1000 miles on it.

[London_Phil]

15v initial charging voltage will equate to a bulk charge value for a multi phased charger. It would also be related to temp, ie lower temps will allow higher initial charge.
What you would expect to see is that value will rapidly fall off to a value below 14.7, but above 12 when engine is running.
You also need to factor in meter accuracy, as a meter reading slightly out can make the voltage look bad.
I had calibrated Fluke meters for work, and they can still vary a bit.
On my 800XC the  volt meter is 0.2v high, so it can show 15.1v at times, but really its just a bit lower, and in spec.
I also note that even with the 600+ watt output, voltage will be lower at tickover, and noticably drop when cooling fan kicks in.

If your interested   https://www.powerstream.com/SLA.htm talks about chargers, and a lot of info is there. It would translate to the bike charging system too.