heated gear, alternator output, headlight bulb

Hoping to keep riding through the cold months, although will try to avoid salt and ice. Just wondering how much heated clothing my V1000G5 can run, with and without lights?
I’ve bought a range of 2nd hand gear, don’t want to end up stranded with a flat battery.
My Acewell speedo has a voltmeter, unfortunately it turns off as soon as back wheel turns, what voltage should I need to keep battery charged ? Is it very easy to install a separate voltmeter to keep an eye on the state of charge? I had a trial run with a heated jacket yesterday, worked fine until I turned on heated trousers as well, blew 5 amp fuse after a while of running both through same fuse, will I be ok replacing with a 10 amp fuse?

Also was wondering of any recommendations for a good headlight bulb, came with a 100w one installed but it is very dim!

well the headlight lamp should be around 55/65W sticking a higher wattage lamp in will not always give more light if the electrical system and wiring cannot supply it, plus its an MOT fail
how clean is the reflector ?
you can have them re silvered that helps
try using a good quality halogen lamp 55/65W ( not ebay junk)
check the voltage at the headlight connections and ensure the earth lead from frame to headlight is not corroded
with the bike running measure the voltage across the battery terminals, and then rev the engine to see if it rises very much
if the regulator is working correctly it should clip it at around 13.8v to 14.4v as a rough guide
I am not sure of the rating of your alternator but you need to find this out then add the wattage of all the lamps including both stop and tail lamp and see what is left, however if the alternator is say 300W you will not get 300W as some is lost in in the change from Ac to Dc and through the regulator and wiring
I usually allow a loss of a third for safety, especially if you have a flat battery, the regulator will allow it p to put out more current to charge it
ps heated suite ar enot much good at low revs, those early regulators tended to clip the voltage too much to prevent batteries boiling, on the old BMW I fitted a police issue regulator designed for traffic work as my battery kept failing when used in heavy traffic with lights on
what is the wattage of your suit and the trousers ? it should be on a label someplace
are they fed directly from the battery via a fuse ?

Rapheal’s right generally 100W bulb is a waste of time, the wiring switches and connectors can’t handle the power. Best bet is 55/60W H4 as a Philips X-treme or some other brand of those high output types. Better results again if you run the headlight via relays straight off the battery, removes all the intervening wiring and connectors of the bike’s loom. Lighting supply must have its own fuse.

This from the factory workshop manual ~
As yours is Tonti bike with Bosch 280W alternator, note this max. 280W (20 Amps) only available at 7,000 rpm according to the above. Otherwise 12 - 15-ish at more normal everyday rpm’s. I.e. expect only about 170 - 180W most of the time. And nowt if bike is staionary and idling.

Some years ago one Saturday I did a trip into London on the Spada that had two 55W spot lights on as well as an H4 in the headlamp, knew I had the normal lights on but didn’t realise the spots were on as well, after a while the engine started spluttering, not running on reserve so took a decko at the instruments, battery was going flat! Voltmeter hard over to the left. Due to slowness of traffic, traffic lights etc. there was never enough power from the alternator to keep it all going! Turned lights off, Vrooomm!! :smiley:

have a read Daniel Stern Lighting Consultancy and Supply
you will see you need full voltage at the bulb a 1 volt drop is a 20% reduction in light output

if running all these extras you will need the high output alternator Stator Kit for Moto Guzzi 1975 - 1992 - Bosch alternator replacement kit original is 20 amps flat out these are 32 flat out and can do 20 amp at 2000 revs

On my LM111 (standard Bosch set up) I always used either twin 60/55 or a single 100/85 headlight.
Vastly improved performance with no problems and no MoT problems.
I also fitted a Police BMW regulator from Motorworks which brings in full power at about 2000rpm.
I did the same with my V1100 Sport (Saprisa) with the same excellent result.
I am thinking abot going LED with my present bikes but failing that will try the 100/85 if I can find some good ones.
I put relays in my headlight in the LM111 and that also increases output.

Sorry Ian that’s bollox, take a look at the chart it wil only do 10 Amps at 2,000 rpm, that’s not “full power”. All the Police regulator does is increase the Voitage a bit, it still cannot increase the current as that can only be done with more rpm. Or, as suggested, a different design of alternator that WILL deliver more current at low rpm.

Thanks for the info so far.
If I test my output at a standstill with voltmeter in speedo will anything over 12v be ok or do I need 12.7 volts or more for battery to be charging?
Will I get a warning, like Mike H, that battery is discharging so I have time to turn things off?
Is there a “how to” on running headlight direct via a relay?
Tried estimating what power is needed to run all kit when I get it, I know there wont be enough with lights as well, but I think I’ll have a switch to run at 60% power, or I could just turn items on as needed.

to be charging you realyy need 13 volts +


spot on from another poster
the ideal voltage for a lead acid cell is 13.8 volts
some one on here does a batteyr monitor device that indicates charge and discharge much more accurately than an Ammeter
Ammeters will deteriorate with age, corrosion, and use and vibration

Well it’s bulwarks that has been running fine since 1984.

I fitted an HID conversion to my headlight.

It’s a bit of a faff and of dubious legality but the MOT man hasn’t ever complained. It gives far more output than an H4 bulb, even the high output ones, but only draws 3A.

Even so I can’t imagine the Guzzi alternator coping with very much in the way of excess current draw.

You need to see anything over 12.5v to have a chance of keeping the battery charged.

Well there are a fair number of people out there with twin h/l fairings who don’t have any problems.
Btw, any 12 volt charging system should be charging at 14.4 volts at max o/p.
This is why we talked in the army about 28 and 14 volt systems, not 24 and 12.
12.5v is absolute minimum unless your battery is no good.

Is there a “how to” on fitting HID conversions?

Also I see you can buy heated grips that connect direct to battery but wont flatten battery. Anyone know if this kind of technology could be fitted between battery and heated kit (I plug it into a lighter socket at the moment, but also use that for charging battery so would expect a different connection would be needed)