The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: bsarider on 15.11. 2009 17:42

Title: A7 plunger electric puzzle 6v
Post by: bsarider on 15.11. 2009 17:42
Today before I set off on a 25 mile ride I checked the lights and all was well the battery had been charged up about two weeks prior and had held its charge.On my return I had no lights or horn took the battery off and it showed 1,3 volts only, put my spare battery on and the lights were back to normal the ammeter shows charge.
 I didnt ride with my lights on today so I would have only used the brake light the switch is not sticking. whats it likely to be bad battery or a regulator problem any feedback would be appreciated.
Title: Re: A7 plunger electric puzzle 6v
Post by: Richard on 15.11. 2009 21:30
Thats a difficult one to answer at this stage, it could be the regulator is faulty and over charging and has boiled the battery, did you check the battery fluid levels?
is it an electronic regulator?
Charge your spare battery until it is fully charged fit it to the bike and start it up the regulator should after a few minutes not let any charge go into the battery the ammeter should show if it is still charging,in which case the regulator will need sorting. If it is regulating properly then hopefully it will have been a duff battery.
Richard
Title: Re: A7 plunger electric puzzle 6v
Post by: bsarider on 16.11. 2009 10:49
RICHARD,
           Yes it is a difficult one let me tell you the latest.
Fully charged my spare battery,fitted it and everything works fine except when you turn
the lights on the ammeter moves over to the plus instead of minus,with the engine running it also goes over to the plus side.I havent checked out the wiring as everything appears to work when I bought the bike and I deceided to run it as is but it looks like I will have to sort the wiring out.My battery which went flat yesterday has charged up and is showing 6.8 volts this morning.I have an old regulator fitted. Alan
Title: Re: A7 plunger electric puzzle 6v
Post by: LJ. on 16.11. 2009 11:05
Alan... If your using an old type regulator you will find it very useful to have one of those battery status monitors as they give you a good idea of what is going on in your circuits. A fast flashing red light shows it is over charging while a green light will show the dynamo is charging the battery correctly. I have one on all my bikes and use the old regs with no problems. Many will recommend the Manortech electronic regulator if you should want to chuck away the old mechanical reg. You do need to be sure everything is working correctly as damage to the dynamo can occur.
Title: Re: A7 plunger electric puzzle 6v
Post by: bsarider on 16.11. 2009 12:22
Where should I start, can someone explain what I should do to locate the problem,its evident that all the lights and brake light seem to be coupled up correctly as they all
working.
 What I think I will do is take the headlight glass and rim off, take the tank off so I can get to everything and trace every wire and make myself a new wiring diagram and compare it to what it should be.
     How do I check the regulator  do they either work or not are they adjustable ?

Its a puzzle why the ammeter moves to + when I turn the lights on?

Thanks for everyones imput   Alan
Title: Re: A7 plunger electric puzzle 6v
Post by: chaterlea25 on 16.11. 2009 17:10
Hi Alan,
Your ammeter will work in the wrong direction if it is connected back to front,
OR more than likely when you charged the battery  a few weeks ago you reconnected it wrong way round
This would also explain why it was flat after your trip!!!!!!
It is more likely that it is something simple so check the obvious before dismantling the bike!!!!
HTH
John O R
Title: Re: A7 plunger electric puzzle 6v
Post by: Dynamo Regulators Mike on 16.11. 2009 19:21
Alan, I agree with John.

The battery has surely got to be the wrong way round. This could easily lead to high currents flowing with a bobbin regulator and would with electronic type as well. Don't know what a BSI LED would show with reverse polarity, whatever the voltage. Best add on (as opposed to replacement) to your electrics is a fuse. Those high current wires run awful close to the carburettor.

Now the reverse connection will probably have repolarised the dynamo. So it will need 'flashing' to restore correct polarity (briefly connect dynamo field to battery live). I assume this should be negative earth for a plunger machine.

Cheers,
Mike
Title: Re: A7 plunger electric puzzle 6v
Post by: bsa-bill on 16.11. 2009 20:57
AFAIK - LEDs only work oneway, connect them wrong and nothing happens.

All the best - Bill
Title: Re: A7 plunger electric puzzle 6v
Post by: trevinoz on 16.11. 2009 21:01
Plunger bikes should be pos earth. All were changed to pos earth in about 1949/50 with the introduction of the E3L generator.
Trev.
Title: Re: A7 plunger electric puzzle 6v
Post by: bsarider on 16.11. 2009 21:26
Thanks for all your replys,in my workshop manual it says that 1947 to 1950 is negative earth 1951 onwards positive earth. My dynamo is an E3L which is the later type and should be on Positive earth.Anyway taking the regulator top off it lookes really crabby
and following the wires to the dynamo and taking the top off its all oiley and the inside is all loose I think the dynamo has to come off and be checked out and at least tightened up, then I could try to see if its generating any power at all and then re connect to positive earth if thats the thing to do.Will i need to flash the dynamo to positive earth? unless you can suggest any alternatives. Alan
Title: Re: A7 plunger electric puzzle 6v
Post by: trevinoz on 16.11. 2009 21:54
Alan,
            It sounds like your generator could do with a major overhaul. Likewise your regulator.
If you know nothing about electrics give them to someone who does.
The regulator is simple to set up if you follow the service sheet instructions but there are a few components which need to be carefully inspected before you start.
Trev.
Title: Re: A7 plunger electric puzzle 6v
Post by: Triton Thrasher on 17.11. 2009 08:57
The only real polarity issue is the dynamo has to be the same polarity as the battery.  "Correct" hardly matters, unless you have an electronic regulator.

Title: Re: A7 plunger electric puzzle 6v
Post by: Richard on 17.11. 2009 22:14
sorry to come in late on this, but I would agree that the battery was connected the wrong way around hence the + on the ammeter when the lights were switched on, also the + showing when the engine was running as more than likley the dynamo was charging correctly but was also charging the battery the wrong way around hence it went flat, the fact that it seems to be at 6.8 volts now may mean it is still ok.
As others have already said
I would remove and service the dynamo, likewise clean the regulator contacts and then refit the dynamo and reflash it, then set up the regulator as per the lucas manual
have a look at this link all you need to know
http://www.bolsover.com/
Good luck
Richard
Title: Re: A7 plunger electric puzzle 6v
Post by: bsarider on 18.11. 2009 09:39
Thanks Richard,
     I now have the dynamo off, cleaned it out, back together again and it lights a 12v bulb quite easily,its a work of art getting it off in the first place.
    What I intend to do next is to trace all my wiring to determine if the bike is positive or negative earth wired and then change it to negative earth.
    I will clean down the regulator and reset it to see if everything is working as it should then I will put on a solid state regulator when I have proved the system.
Thanks for all the  messages I will keep posting. Alan
Title: Re: A7 plunger electric puzzle 6v
Post by: bsarider on 28.11. 2009 18:54
Well it looks like the ammeter wires were on the wrong way around,checked out all the wiring and its wired for negative earth, re polarised the  dynamo to neg earth and connected up after swapping around the ammeter wires everything seems to work properly and when the lights are turned on the ammeter shows a discharge. Just got to refit the timing side outer cover and fire her up hopefully the problem is solved. Do I grease the dynamo chain or is it oil fed .I cant see any oilways? Alan
Title: Re: A7 plunger electric puzzle 6v
Post by: muskrat on 28.11. 2009 19:14
G'day Alan, the chain should be greased with low temp grease so it melts when hot. Don't forget the gasket between the dynamo and inner timing cover. I did, YUCK. I used red grease so at least I knew where the mess came from.
Cheers
Title: Re: A7 plunger electric puzzle 6v
Post by: unclemeat on 29.11. 2009 23:18
I had exactly the same problem with both my Golden flash plunger and my M21. Swapped the leads on the battery and everything was ok.
Title: Re: A7 plunger electric puzzle 6v
Post by: bsarider on 30.11. 2009 16:55
http://www.britishonly.com/pdf/bsa/sectionY_BSAservicesheetno808.pdf

If I wanted to install a small 6v bulb to tell me when the bike was charging(i.e. the bulb would go out) where would i wire it in ? Alan
Title: Re: A7 plunger electric puzzle 6v
Post by: a10gf on 30.11. 2009 17:56
Quote
to tell me when the bike was charging
...your ammeter not working ?

If you're thinking like having a red lamp (like in a car) when charging stops, thinking loud, you'd need a dynamo-driven relay, which upon loss of voltage from the dynamo connects a lamp to the battery.
...which means when parked the light will stay on until the battery is sapped (unless you ride the bike most of the day)  *smile*, as there is no switch to turn all power off like in a car, so this is not the solution lol
That's why an ammeter is such a good solution, drains no power, very few parts, and shows both charge and discharge.
Title: Re: A7 plunger electric puzzle 6v
Post by: groily on 30.11. 2009 18:32
Yup, you could do it, but just another point of possible failure really that would only tell you in very basic terms what an ammeter tells you with more precision. Easy enough to do with coil ignition and a switch like on a car, but as a10gf says, not a great plan on a bike. The gizmo has to measure when the field is drawing more than D is sending out - ie when the battery is being drained. If you look at the things old cars have, you'll see behind the bulb holder, or in it, there's a coil etc. More trouble than it's worth I'd also say. Just keep your eye on that needle from time to time, and you won't go far wrong. If the needle flickers like a good 'un, then maybe worth getting a decent ammeter with proper damping - a lot of the modern replica ones are ****. Many of the old ones have a small adjuster screw to keep the needle under some sort of control . . . 
Heresy though it be, I like the 2in Miller ammeters with a white face best. I can read them without spectacles, and they are really well damped. I trepanned the (non-original) h/lamp shell on my A to take one. No regrets, as decent electrics make one of the biggest differences between Toytown playing and Real Life riding, especially this time of European year!
Title: Re: A7 plunger electric puzzle 6v
Post by: bsarider on 30.11. 2009 19:13
Thanks for that,I think as you say its not worth the problem . Back to fitting my reworked centre stand tonight if the cold  can be braved. Alan
Title: Re: A7 plunger electric puzzle 6v
Post by: bsarider on 02.12. 2009 10:32
Well the plot thickens,fitted the centre stand back on complete with a foot bar so I can get a bit of heave ho!!! on the lifting handle. Started the bike and the ammeter just flicks about as if its not connected,took it off and theres a little brass nut floating about inside. Ordered a new Ammeter from Lightening spares awaiting its arrival keep you posted. Alan
Title: Re: A7 plunger electric puzzle 6v
Post by: bsarider on 08.12. 2009 19:53
Well this is the final posting on the matter,Fitted the new Ammeter,checked out all the
wiring onto negative earth,fitted a fuse from Battery Live to Ammeter, Fitted a Fuse from new solid state regulator to ammeter,hey presto it charges like a gud un.It looks like the culprits were the faulty ammeter,dynamo and unknown regulator. thanks for all you help
Alan