The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: John Roberts on 14.05. 2025 19:29
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Hi all,
I've got a 1955 Shooting Star which I got last September. I've only done three hundred and fifty miles on it and noticed no electrical problems but the other weekend I noticed that there was no charge in the battery as the horn wasn't working. I tried charging the battery which wasn't playing, took it out of its holder and saw it was dry. I fitted a new battery and all seemed well except that the ammeter on the bike is across to the far right pretty much all the while when the bike's running except at low revs even with a light on. Is this worrying? I'm wanting to ride it approximately forty miles at the weekend to take part in The Distinguished Gentleman's Ride.
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G'day JR.
Sounds like the regulator is playing up. One of the resident "sparkies" will be along soon.
Many years mine did that. I think I disconnected the dynamo and rode with a total loss system, charging the battery at night till the DVR2 arrived. Never had a problem since.
Cheers
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Thanks for that! I'm happy with the dead loss system plan to an extent, I'm just worried that with lots of extra electricity flying about the place something else might be getting damaged. I'll look at replacing the regulator either with a reproduction one or a solid state one.
Thanks again,
John
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Is the ammeter registering a high charge except when the lights are on? Why was the original battery dry? Boiled up due to overcharging? If so I would reckon a problem with the voltage control unit. Otherwise the new battery won't retain charge and the system is working Ok but unable to charge the battery. Always assuming the ammeter is wired correctly. New battery is easiest to check, rate of charge on battery charger, and does it hold the charge.
If time is short the bike can be run with the battery disconnected. You'll still get lights of sorts as the dynamo output will be uncontrolled.
Brake light and horn used to be wired on their own circuits, to give some safety factors in the event of major electrical failure. For daytime use (no lights) a freshly charged good battery will power brake light and horn enough to complete DGR, by disconnecting the main battery supply to the loom but leaving brake light circuit connected, as ever if it is still wired as originally. Alternative is to disconnect dynamo, as Musky's trick, but this leaves all reliant on the battery for main lighting.
Swarfy.
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The ammeter is registering a high charge pretty much all the while, lights off or lights on except when the engine's at low revs; as soon as the bike's properly underway when the needle goes right to the stop!
I've ordered a solid state regulator, AND a reproduction electro-mechanical one. I'll do the DGR this weekend and fit either one then; to be honest whichever is easiest!
Thank you for your advice!
Regards,
John
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There are two set of points in a Lucas regulator. One set is above a coil and are normally closed until rising voltage in the coil causes them to open, this is the regulator coil. The other set of points are between the other coil and the back plate. These are normally open, rising voltage in the coil will cause them to close and connecting the dynamo to the battery and start charging, this is the cutout coil. It sounds like the points on the regulator coil are stuck together and need separating and cleaning. Hope this helps.
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Given it's now Thursday, I think I'd follow Musky's suggestion just for now.
There is a series of things you could do, but maybe not in the time available . . .
BSAreg's stuck regulator points is very likely, but it could be a short between F and D at the dynamo, which would also chuck all power out at all times. A constant 8A or more charge rate won't be doing anything any good at all and could (will, probably) cause dynamo failure.
You could quickly measure the voltage across the battery with the engine running above tickover though if you wanted, and if it soars to 'lots' with a few rpm then there's no regulating going on for whatever reason - or it speaks to a very flat battery indeed which, if the charge rate stays so high, says the battery won't accept a charge. If you're at 6v, you don't want to see more than about 7.5v - anything in the teens or above is a recipe for potential extra expense!
Have you blown any bulbs I wonder? Uncontrolled voltage has that tendency, as well as boiling batteries dry.
So I think it's best not to run with the dynamo connected unless you can make the problem go away in the time you've got.
If the battery can support a brake light for a few hours, all well and good, if not - hand signals!
And Yes to a DVR2 - and imho No to a replica mechanical regulator. Better to have the original sorted if you don't want to go electronic, as they are far better-made than any copy I have seen. This is an area where you get what you pay for . . .
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Disconnect dynamo and as temporary fix, go for sealed lead acid 6v 4.5ah rechargable battery from Amazon or similar, cost about £12.00, should last for length of your ride to support brake light and horn
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Thanks to all! The second time in a few weeks that this forum has saved my bacon! I think bsareg hit closest to the bull with his sticky regulator points; I squirted some contact cleaner in there and wiggled a .015" feeler gauge about a bit. Whether it's cleaned some gunge out of there or whether the armature was stiff (I gave that a wiggle) but anyhow upon starting the ammeter by the headlamp seemed to indicate everything was good (it's spending almost all its time on the positive side but nowhere on the crazy high side). I'm very relieved, and quite an easy fix in the end), so thanks very much again!
Ride safe,
John
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John,
In case the message did not get through loud enough, if you are going to ever buy an electronic regulator get the DVR2 - they are super - others, not so much.
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To echo that, do NOT get a similarly-named Vreg2 or even a Wassel as they're both utter crap.
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'Utter crap' might be a wee bit strong for the V Reg 2 I think Rex.
Alan Osborn (whom I don't know from a bar of soap, so no bias here) is not a numpty (and his parallel-universe alternator regulator/rectifiers are excellent value and I have used them extensively).
To see how a few 6v dynamo voltage regulators compared one to another a while back, here are some graphs demonstrating performance on rising rpm and descending rpm with and without loads applied: wherein you can see that the V Reg2 is in a much better class than the Wassell-branded ones, but that it does fall short of the DVR2.
It came out below par for 'not cutting out cleanly' on descending rpm - ie allowing a discharge at tickover speeds - which the DVR2 doesn't, and cut-in on ascending rpm was also less strong.
So yup, on this basis the DVR is certainly a better bit of kit (and I've been a fan of them forever), but none is infallible. I've had the odd failure with all of them over the years, and several different ac reg/rects as well fwiw - but the service life of the DVR is right up there. I know of a good few still working fine at 20 years old including one of my own, and I was testing one I supplied for a friend in 2011 only yesterday. It was fine, regulating steadily at 7.2v near enough with or without loads applied - it was the dynamo armature that had given up.
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I don't know Mr Osbourne personally either, but after one of his units left me stranded in France (at an event you'll be familiar with Bill) I had the misfortune of attempting to liase with him, and wished I hadn't tried, as his customer skills are abysmal.
The unit sometimes seems to forget to "switch on" and start charging, and is pretty much useless under 30 mph ie, around town.
According to the reports on the "Matchless Clueless" site some years back, my experiences are far from unique.
DVR2 every time.
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You definitely have the edge on me there Rex - never had to test the 'customer service' aspects of AO Services. Doesn't sound good, that, so I hope I never have to - while by contrast ManorMike Hutchings of original DVR (and this) ilk was always a pleasure to deal with / discuss any issues with. As, I am told, are the new owners of the brand.
I had a very similar experience to yours in trying to get any sense out of whoever supplied me with a Sparxx alternator gizmo that died on a friend's Trihard after about 200 miles. Said they 'couldn't' (as in 'not able' to) test it and weren't interested in offering a replacement, my inference being that they thought 'I had done something'. Losses cut as just too complicated to argue interminably with a brick wall from here, and a Podtronics fitted, still working 10 years later.
It has to be accepted that things sometimes go wrong - it's how they're handled makes all the difference. It's particularly tricky with electrical bits perhaps, as the supplier can't see what a buyer does with them, and there are many ways inadvertently to inflict damage on some of them!