Generator lamp oddity

IanPorter

IanPorter

Registered user
Joined
Jun 2, 2010
Messages
281
Reaction score
0
Location
derby
Got myself an Airhead this week (R80 with sidecar)

It’s running a car battery in the sidecar and doesn’t seem to be charging very well

What seems really odd to me is the generator lamp doesn’t light when I turn on the ignition BUT it does light if I through the kill switch to off

Now that can’t be right

Any ideas?
 
Just as a start, get a meter & see what voltage the battery is receiving, both static, running at tickover, then at say 3000+rpm. Should give us a clue.

It sounds like a real bodge job, possibly a total loss system, hence the big battery rather than a normal bike battery.
 
12.3 volts ignition on
12.4 at tickover
13.4 at about 3000rpm

Tested across the battery terminals
 
SO its getting some charge (a tad low maybe) so you know its at least working to some degree.

As you may know the generator light acts as the exciter (on a standard airhead charging system that is) so the fact that it charges with no light evident suggests that it may have some kind of aftermarket system fitted - this non generator light behaviour is typical of some of those systems. I would pop of the front cover of the engine and have a look in there to see if this is the case (Mikeyboy on here is pretty well versed in this kind of thing) Anyway, unless you need the PO's lash up system of a car battery (which is probably to large a capacity for the bike system- unless its been upgraded maybe) I would totally revert to the standard bike battery and remove the PO's wiring etc - I suspect this would probably cure most of the ills.

Just my initial not thought to deeply about it 2p worth :)
 
Could be I guess
I can see under the tank there is the original rusty regulator

Think I’ll get the tank off too and have a look at the wiring under there while I’m at it
 
The battery size is irrelevant,
The charge light thing is odd ,but I can’t offer any explanation as the bike isn’t in my workshop.
As to advice,to move forward.
It really depends what you want and need from the electrical system,
If ,with it being an outfit,you want more lights,heated kit etc etc.
I would dig deep and upgrade the whole caboodle to a 600watt kit from motorworks.
This will charge at over 14v just off idle .
Or if your needs are less,you could fit an electrex rectifier and a voltmeter just for reassurance.
However,you may well find you have other issues with the charging circuit as you investigate further ,so it may have been more cost effective to go with a decent upgrade in the 1st place
 
You say rusty regulator, on some bikes the wiring harness ground is through the regulator screws, and bad earths can be the source of odd problems.

It is possible to bypass the warning light, clue it has been done is an extra wire with a resistor in it spliced into one of the wires going to the regulator.

New regulators are cheap enough from folk like EME, and would probably raise you charge voltage if the existing voltage concerns you, and they also sell a low priced bypass kit which stops you being dependent on the filament in the warning lamp to charge your battery.

FWIW my G/S has never had any more than 13.5 peak charging volts and that has always been sufficient to fully charge the AGM battery, and the battery volts are almost the same as when the battery was new, 8 year/230,000 km back so it seems it is easier on the battery too!
 
Thanks guys
Going to pull the tank and take a look at the wiring under there first as it looks somewhat neglected from peeping under the tank!

It was my intention to upgrade the generator at some point anyway so this might bring that forward
 
so it develops...

I have no generator lamp at all now :( (bulb is good)

earths are good when tested with my meter (0.3 ohm)

the plug on the bottom of the rectifier just fell off when I touched it as the crimps were loose in the housing, pushed them back home but no different

popped the front cover off (battery isolated when I did)

I have nominally 12v at the blue/black wire on the brushes, if I pull the cable off the regulator it drops to 0v

reconnected the regulator and if I then pull the cable off the back of the clocks I still have 12v!

I'm guessing the lamp has been bypassed?
 
found it!

there's lamp bypass hidden in the loom feeds 12v back to the lamps so same potential each side = no glow :)

no idea why it was lighting up when the kill switch was thrown though

anyhow, plus side is I know more about the bikes electrickery
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
You must log in or register to reply here.

Similar threads

Charging Issue
Replies
15
Views
571
Will O The Wisp
Mad Hatter
Have I diagnosed this right?
Replies
18
Views
1,809
ChasF
ChasF
BMW r1200GS lc 2013 problems
2
Replies
24
Views
1,604
Yetiboy
Mad Hatter
Need some help with ignition timing
Replies
4
Views
511
Mad Hatter
Mad Hatter
R1100GS Final Edition hamfistedness. Woe is me.
Replies
15
Views
684
Lord Snooty
Lord Snooty


Back
Top Bottom