Just recently fitted some Datatool Therma grips to my SP3, like the design of them with the control being part of the hand grip, very neat.
However they will not work, unless you have the motor spinning at about 4000rpm. After speaking with the manufacturer they said the probable reason is, is that the charging system, at lower revs, is not producing sufficient electrical noise from the charging circuit for the grips to work.
My bike has the Bosch charging system which has never given me any problems.
I still would like to fit heated grips to my bike, so can anyone recommend a make of grips that will work?
“Electrical noise” eh?
Do you know what’s the power rating?
This is the explaination i was given by the technical people.
He also said that i was not the only Guzzi owner who has had this problem, with these grips.
There is nothing in the installation guide or on the packaging that indicates the power rating.
I have oxford grips on my breva, they have a circuit on them that detects battery voltage, if it drops below something like 11.8 it shuts the unit off
I presume to prevent flat batterys
I usually have to rev it a little before they will lock on, although I have them wired via a relay to shut down with the ignition
I have Oxford grips on my VFR. Wired to only work when ignition on. I’ve never had any issues with them not working, but maybe are a simpler version.
Hello,
I suspect that them not working correctly is due the voltage sensor in the system. Try this disconnect the feed cable from the battery start the engine put the lights on as this is the most realistic running condition. Run the engine just above tick over or just as the charge light goes out. Keep it at that speed and reconnect the feed cable. Do the grips get hot? If yes that is fine. Now let engine tick over often the charge light will come on with a guzzi. Now increase revs. Do the grips stay hot. If yes no probs. you need to fit and on off switch and only switch the grips on when the engine is running at above tick over to allow the alternator to be ‘excited’ if the grips start to cool then they are preventing the bike voltage reg from triggering and allowing the alternator to be excited so it then self generates. This is more difficult to solve. It would involve fitting a switch and when you notice the grips cooling switch them off and then back on. A bit crude but it would work the Bosch system will easily run heated grips and lights but not necessarily at tick over. I wonder what sort of wattage these grips are. I hope that sort of make sense. I am sure some electrical guru will disagree with this prognosis.
He’s already said no heat below 4,000 rpm.
Chris if you could accurately measure the resistance we can calculate the power rating. (?)
I know the grips do not work below 4000rpm. However what I am saying involves disconnecting the grips then reconnecting them when the engine is already running. Also worth checking or knowing is the battery old. It may have started to lose its peak performance causing too much voltage drop under load. This is detected by the grips sensors and refuses to play. A simple battery test on bike. Put volt meter across battery. Press starter. If voltage drops below 10v. Duff battery. Poor battery connections (cheap to do), poor connection to starter or poor starter. However we start at the battery. When engine is running voltage should be around the 14v mark. If you charge the battery let it rest (hours) before testing. Even an old battery will seem ok immediately after charging.
Thanks everyone for the replies and suggestions.
I am going to take the easy route out of this problem, as the dealer has agreed for me to return the grips for a full refund which is what i’m going to do.
I’m going to get a pair of R and G heated grips and wire them via a relay, so they only come on when the ignition is on, as it seems they do not have this circuit in them that detects the voltage.
I will report back and let you all know how i get on.
as a retired blacksmith, I now nowt about electrikary, so silly question time. if you whire the grips directly to the battry (like I have) will that not cure the problem. 
my are oxford with the sensor that detects movment ( vibracion) and turns the grips of after two miuets if you for get,
Have just fitted the R and G heated hand grips that i bought, to replace the datatool grips that i was having no joy with.
Started the engine up, turned on the grips, and after a few minutes the grips are getting nice and warm.
So now i can go for a ride and have warm hands, when the weather its nice and sunny, but still cold.
I had charging problems on my SP3 probably due to worn brushes and dirty commutator ring but I didn’t resolve it before selling it on. The headlamp used to dim when I put the brakes on, I swapped the two rear bulbs with LED items and that problem went away. I think that the charging on the SP3 was marginal and any additional equipment could be pushing it too far. However these are my own opinions and I do not have any meter readings to back this up
Chris. Worn brushes yes but a dirty commutator ring is unlikely.
Commutators are supposed to be a dark chocolate brown colour.
Far more likely that you needed to clean the negative collection point on the battery tray.