The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: bikerbob on 11.04. 2015 13:28

Title: Charging Problem
Post by: bikerbob on 11.04. 2015 13:28
I have a 1956 A7. When I bought it last year it was not charging and the previous owner had advertised it as charging and in between buying the bike and picking it up the then owner fitted a new mechanical regulator but it did not solve the problem. When I investigated further the reason for the not charging was because the Dynamo chain had come off. Fitted a new chain and everything OK. Bike has been off the road over the winter as I had work to do on the engine and gearbox. Bike now back on the road went for a run and all OK for about 30 miles when suddenly not charging even though it was charging alright with the head light on. When I got back home started the bike in the garage and tried pressing the points in on the regulator but still no charge. I connected the dynamo terminals together and using a multimeter got a reading of 7.5-8.5 volts on tickover which increased to 12-13 volts on a fast tickover. So it appears that the dynamo is OK so I reconnected the dynamo leads then took a reading off the battery just over 6 volts,started the bike and on tickover getting a reading of approx 7.5 volts increase the revs and the reading goes up to approx 9 volts but still no movement on the ammeter which shows the same discharge reading whether the engine is running or not with the lights on. Is the problem the ammeter or the regulator or something else. Thanks. I get no reading on the ammeter with either engine running or not when I press the points on the regulator.
Title: Re: Charging Problem
Post by: beezermacc on 11.04. 2015 13:37
First of all, the regulator should not allow the battery to rise to anywhere near 9v, something just over 7v is OK, so the regulator is definitely duff. It sounds like your ammeter is also duff as it is allowing current through but not showing a reading. I'd change the regulator first as, at present, it is cooking your battery. After fitting a new regulator (or fixing the old one but probably not worth investing too much time in it) see how the ammeter looks. Unless it has miraculously woken up it is likely you'll have to change that as well.
Title: Re: Charging Problem
Post by: Triton Thrasher on 11.04. 2015 13:45
Sounds like it is charging, but the charge is not showing on the ammeter. The only faults that develop in an ammeter that is passing current, are mechanical faults with the needle, such as stickyness, or falling out of the bearings.

Did the ammeter work before?

9V is too high and points to a faulty regulator, as said. Are you happy with the accuracy of the 9V reading?  Digital multimeters can be erratic.

New pattern electro-mechanical regulators are not highly regarded. Get a DVR2 electronic one.

Title: Re: Charging Problem
Post by: bikerbob on 11.04. 2015 17:20
Thanks for the replies. I have been out to the garage again and the reason for the high voltage reading was because the multimeter was resting on the back mudguard and it was affected by the vibration as soon as I to lifted it up the voltage reading dropped to between 6.5 and 7.5 volts but it was never a steady reading and did not alter when I switched the headlight on only the ammeter was showing  a discharge all the time the lights were on but never a charge when the lights were off. When it was running OK and the ammeter was showing a charge it was always a high reading sometimes the needle was right across showing a full charge and only dropped to about half way with the lights on but it did vary sometimes to what I would say was acceptable showing a discharge with the headlight on at tickover but would go to charge when the throttle was opened up. The battery is only a few months old and is fully charged.
Title: Re: Charging Problem
Post by: Triton Thrasher on 11.04. 2015 17:24
I don't understand much of that.

Does the headlight get brighter, when you rev up off idle?

Just go for a ride. If the lights don't all go out, it's ok.
Title: Re: Charging Problem
Post by: bsa-bill on 11.04. 2015 17:50
IMHO needle wont move a lot if the battery is good and fully charged, in which case I'd would expect it to show a discharge when the light are switched on full beam but with a good system and battery it would soon settle back to no deflection (with engine at typical running speed say 40 + mph)
Title: Re: Charging Problem
Post by: bikerbob on 11.04. 2015 18:43
Thanks for the replies. Tried again battery reading without the engine running is 6.08 volts turn the headlight on and ammeter assuming it is a 8amp ammeter it reads discharge at approx 6amps. Start the engine with headlight off and on tickover or increased revs battery reading fluctuates between 6.4 -7.8 volts the highest reading was very briefly 8.3 volts. turn the headlight on and ammeter still shows a discharge of approx 6 amps with engine running which does not change or the brightness of the light. Battery reading  fluctuates between 6-7 volts on fast tickover but light brightness does not change. When I get some time maybe tomorrow I will swap the ammeter over from my A65 which has a 12 amp ammeter and see if there is any difference at least it may rule out the ammeter.
Title: Re: Charging Problem
Post by: bikerbob on 14.04. 2015 10:39
Tried a different ammeter and no change so I am going to order a new regulator as the dynamo is putting the power out, I will order one of those DVR2 electronic regulators as they seem to the best reports. Thanks once again  to those that gave advice.
Title: Re: Charging Problem
Post by: a101960 on 14.04. 2015 14:06
Tried a different ammeter and no change so I am going to order a new regulator
There ammeters, and there are ammeters. Most, but not all of ammeters that are widely avaiable are un damped. What this means, is that all to often the pointer will oscillate due to vibration. Maybe it is a figment of my imagination, but I do not recall this being an issue years ago on either singles or twins. On some ammeters there is an adjusting screw that is supposed to eliminate the problem of the pointer wildly thrashing from side to side. By giving the screw a slight tweak some degree of friction damping is supposed to be applied to the pointer. In practice I have found that sometimes this works, and sometimes it does not. Finding an ammeter that gives a good clear steady indication is a bit of a lottery. The DVR2 is a good piece of equipment, and it will be even better if you also opt to fit the belt drive kit in place of the chain drive. That said, from the charging behaviour you are describing it might well be possible that the ammeter behaviour is muddying the waters even though you have tried a substitute ammeter.
Title: Re: Charging Problem
Post by: oldbeezageezer on 14.04. 2015 23:00
I have a similar charging issue with my A10. I have run the checks from the dynamo and they check out ok. Checking the regulator in situ I don't get any readings and have resigned my self to getting a DVR2. But.... on my last run out with no lights on, I noticed that the ammeter was showing a slight discharge and when I opened her up, the discharge shot across to 6 amps discharge. Back in the garage on tick over the amp needle was steady in the middle but as soon as I gave it some revs it went to 6 amps discharge and turning on the lights didn't make any difference.
Any ideas anyone?

I will still go ahead with the DVR2 and see what happens then.
Title: Re: Charging Problem
Post by: duTch on 15.04. 2015 00:51

 Can only assume the amp meter is connected properly. ..?
Title: Re: Charging Problem
Post by: Seabee on 15.04. 2015 12:52
Old Beezageezer,

Try re-polarizing.  Sounds like you may be "charging" backwards?

Title: Re: Charging Problem
Post by: bikerbob on 15.04. 2015 18:52
Fitted the DVR2 regulator today and everything back to normal did have a small panic when I started it up charging Ok with sidelights on then put headlight on still charging but when increased the revs the headlight went out then after switching off then on again same thing OK until you increased the revs  turned out to be a dodgy connection in the dip switch now all fixed.
Title: Re: Charging Problem
Post by: oldbeezageezer on 15.04. 2015 20:41
Hi Seabee
sorry, not familiar with the term 're-polarising'. Can you explain please. Your Golden Rocket looks good.

bikerbob where did you buy the DVR2 and what sort of cost was it please?
Title: Re: Charging Problem
Post by: Seabee on 15.04. 2015 21:05
Do a search on this site for dynamo polarizing and you will find heaps of info.
Title: Re: Charging Problem
Post by: bikerbob on 16.04. 2015 14:53
To oldbeezageezer bought DVR2 from Dynamo Regulators Ltd cost was £49 including postage in the UK. If you type DVR2 into google it will bring up their website.