Battery not charging

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nodrog
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Posts: 12
Joined: Mon Jan 01, 1990 12:00 am
Location: WORCESTERSHIRE UK

Battery not charging

Post by nodrog »

Bike: 1960 G3, alternator model, standard except for a solid state rectifier.
Whilst riding I noticed that the ammeter was showing no charge. Got the bike home OK.
Tested the battery: 6.3v, 5.9v with the lights on.
With the bike idling 6.1v & 5.9 with the lights on. Increasing engine revs made no difference.
I therefore concluded that the ammeter was telling the thruth.

Tested alternator output with a headlamp bulb with the lamp across all 3 wires. This gave a bright light which incresed with engine revs. Across the alternator wires to earth with no current evident, so presumed stator was not shorting to earth.

Tested output from the rectifier across brown/purple wire. At idle 0.34 amp, with the lights on 1.4amp. With greater revs this increased to 1.8amp.
I'd got spare rectifier so I tried that which gave the same outputs.

At this stage I'm getting out of my depth. Could this mean the lighting switch is faulty? Can I test for this before purchasing a new switch? Perhaps this the time to go 12v?

Any help appreciated.
Last edited by nodrog on Sat Apr 27, 2019 10:43 pm, edited 1 time in total.
bob121
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Location: WEST MIDLANDS UK

Re: Battery not charging

Post by bob121 »

What's the output of the alternater.
Mick D
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Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Battery not charging

Post by Mick D »

bob121 wrote:What's the output of the alternater.
Hi

Yes, it would help if you gave the voltage outputs of the alternator and regulator.

It's very easy to continuity check the switches, does your meter have a continuity beeper?

Regards Mick
nodrog
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Posts: 12
Joined: Mon Jan 01, 1990 12:00 am
Location: WORCESTERSHIRE UK

Re: Battery not charging

Post by nodrog »

Thanks gents for responding. I've also looked at the useful Chris Read/Al Osborne tech. article on this web site. I will do a bit more research and let you know how I get on but i'm away for a week so it will take a while.

Mick; my G3 does not have a regulator, the alternator output is controlled by the lighting switch.

Gordon
Mick D
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Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Battery not charging

Post by Mick D »

nodrog wrote:Mick; my G3 does not have a regulator, the alternator output is controlled by the lighting switch.
I know that :oops: :oops: meant rectifier , typed regulator :roll: :oops: :oops:

Where's my coat.

Regards Mick
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clive
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Location: LONDON UK

Re: Battery not charging

Post by clive »

My immediate thought, is there actually a problem? I cannot offer technical advice but I can offer personal experience. You got home the battery was charged. I do not actually have a Lucas alternator bike but i do run an Alton on a couple of bikes.
With a battery in good condition and no lights on this will normally not show a charge. This is because the alternator produces enough to keep the battery fully charged and the fancy controller unit reduces the charge to stop the battery being overcharged and damaged.
So I would expect to see the following. After a good ride at some speed with no lights on, no charge. Turn the headlight on and at tickover about 3 to 4 amps discharge. Blip the throttle and this should show less, pull away and travel at 30 plus and it will show no charge or a very slight discharge. Stop or travel in slow traffic in town with the headlight on for a while then travel above 40mph and you should show charge as the battery gets back to normal charge state.
Finally your alternator is lighting a bulb and it gets brighter with revs which likely means its working.
clive
if it ain't broke don't fix
jack clegg
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Joined: Wed Feb 01, 2017 1:48 pm
Location: BUCKS UK

Re: Battery not charging

Post by jack clegg »

Fit a Battery Status Monitor from Paul Goff. The easy way to keep tabs on charging system.
John Marshall
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