The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: BSA500 on 04.09. 2017 09:10
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Strange one. Was riding to work with the lights on when the ammeter showed a massive overcharge. Fuse blew. That protected the reg and lights. I understand how a short happens but over charge ???. Its a 12 volt dynamo, with dvr2 all quite new and a new battery reason/s ?
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Sometimes a poor connection or frayed wire will cause a high charging rate to show on the ammeter. I would start with the basics and check all connections, bullet, blade and screw type.
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D & F leads touching ?
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I will go through the connections. I got the tool roll out of the tool box last night so I will check I haven't dislodged the reg wires etc.
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Oh the fuse did it's job and no damage :)
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Was there a bright light in the sky? You may not want to share but did you get probed?
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must be a short or a regulator failure? even then you'd have to have some revs on. lucky you installed the fuse!
if you figure our what happened please post back - curious.
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Still investigating. Did a quick check no visible issues. Rode it again with the lights on and after 5 miles with acceleration popped the fuse again. The only thing I have done is replace the rear light. I have since checked all the reg connections and replaced the rear bulb with the original one. I will check with lights off and if that's ok with lights on.
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Also did a continuity check along the F/D wires and that was clear.
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Ok ran it into work today no lights on and the charging/fuse were fine. I did check connections etc so I may have fixed it. I will run with lights on and see what happens. Fingers crossed.
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connections go lose/open. your problem is more likely a short... are there any old grimey clusters of connections? any infestations of electrical tape to clean out?
nothing like an intermittent wiring fault to test your patience *conf*
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the rear light connections were quite grimy with lots of black tape wrapped around it.
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Hi,
Dipswitches are a favourite place to find short circuits *problem*
John
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OK more testing.....
Lights off all things as they should be-slight charge showing battery fully charged
Pilot and rear light on- balances just fine no issues
Headlight on-pop goes the weasel
So headlight wiring/main switch/handlebar switch to check. Strange how it goes to over charge rather than shorts to discharge-or does the reg overcharge when more demand is made of the system. Anything else? also I need some more fuses :!
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It goes to over charge because the generator is feeding into a fault.
You are reading the output from the generator, not the battery.
Is your light circuit connected to the generator or the battery side of the ammeter?
If connected to the battery side, this will happen.
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Can't offer suggestions about your issue yet, but I'm having a similar thing that I haven't managed to yet identify....had a headlight fuse blow a couple of times but not for a few days now- keeping tabs on this...
Someone on here posted a link a couple of years ago about resettable fuses like these below, they don't fix the problem, just saves on fuses (just an example );-
http://www.ebay.com/itm/Marine-Resettable-Blade-Fuse-Manual-Circuit-Breaker-5A-7-5A-10A-15A-20A-25A-30A-/311886307406?var=&hash=item489ddf604e:m:mtiUI4yBUP_DXSUtOQ9SoXA (http://www.ebay.com/itm/Marine-Resettable-Blade-Fuse-Manual-Circuit-Breaker-5A-7-5A-10A-15A-20A-25A-30A-/311886307406?var=&hash=item489ddf604e:m:mtiUI4yBUP_DXSUtOQ9SoXA)
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More testing... as before no blowing before the headlight is on. I watched the ammeter as the revs increased and it flicked into the positive a couple of times then a 4 amp flick and fuse gone.
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It goes to over charge because the generator is feeding into a fault.
You are reading the output from the generator, not the battery.
Is your light circuit connected to the generator or the battery side of the ammeter?
If connected to the battery side, this will happen.
Its always been wired this way so does this suggest a fault that has occurred in wiring or reg?
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Anyone suffered similar issues and cured????
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It goes to over charge because the generator is feeding into a fault.
You are reading the output from the generator, not the battery.
Is your light circuit connected to the generator or the battery side of the ammeter?
If connected to the battery side, this will happen.
Trev I think i get what you are saying - if the lights are connected to the battery side of the ammeter then the extra current of the lights (and battery charge current) could show a high reading as the genny/reg tries to power them both (yes?) especially when the revs are up.
and there must still be a fault, or two, to account for the sudden spike. And weird that the DVR2 will allow such a lot of current to flow out of it. however if the fault (a short) was in the headlamp wiring/switch then yes that would account for the spike at least (lets hope the DVR2 is still ok - thanks to the fuse). If the wiring and switch check out OK try a different headlamp bulb. (remembering headlamp and tail lamp are on the same circuit). I'd be suspicious of that switch.
BSA500 - I think all the wiring diagrams show the only things on the battery side of the ammeter should be the battery and the horn (like, why show the occasional current spikes of the horn) and it would probably be wise to re-wire to that
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It goes to over charge because the generator is feeding into a fault.
You are reading the output from the generator, not the battery.
Is your light circuit connected to the generator or the battery side of the ammeter?
If connected to the battery side, this will happen.
Trev I think i get what you are saying - if the lights are connected to the battery side of the ammeter then the extra current of the lights (and battery charge current) could show a high reading as the genny/reg tries to power them both (yes?) especially when the revs are up.
and there must still be a fault, or two, to account for the sudden spike. And weird that the DVR2 will allow such a lot of current to flow out of it. however if the fault (a short) was in the headlamp wiring/switch then yes that would account for the spike at least (lets hope the DVR2 is still ok - thanks to the fuse). If the wiring and switch check out OK try a different headlamp bulb. (remembering headlamp and tail lamp are on the same circuit). I'd be suspicious of that switch.
BSA500 - I think all the wiring diagrams show the only things on the battery side of the ammeter should be the battery and the horn (like, why show the occasional current spikes of the horn) and it would probably be wise to re-wire to that
Okay lots to try. Lucky that the mot testers f****d up today and I now have week to fiddle about. Thanks I will work through this.
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No work today, so I'll do some research...Mine is Standardish system though- 6V (- ve earth) & mechanical reg, so obviously a different animal.
To sum up what it's doing is; lights on- full discharge. Engine running, ammeter shows various charge- up to full (~8A) Lights on; cuts it back to ~just above 'neutral'...I think, because it varies a bit.
Battery is ok, shows about ~7.? running and ~6.2 at rest, even when laid up for 7 weeks (analogue V meter 'semi-permanently' mounted).
I suspect my cut-out needs adjusting, as if I recall I mixed up the value last time (a few months ago)...and I rewired the dipper switch the other day and haven't popped a fuse for a while... *dunno*
may or not be of help to you though
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After reading the above posts I'm thinking I should fit an in-line fuze whilst I'm replacing the wiring loom on my 59 GF. What amp fuze should I use *????* (6 V electrics with standard regulator and lights).
Cheers
Tim
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Good idea.
25 amp or so should do. It will protect against short circuits. And save the wiring from becoming a molten mass.
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i'd use a 15A fuse on a 6v
e3l is 60W = 10amps at 6v (actually specced at 8.5 amps at 7v) plus some headroom
i'd fuse the horn separately as they suck a bit
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I'd go for 25 A, rather than 15 A.
20 A is common as a main fuse on 12 V Brit bikes. 6 V systems pass more current.
I like to have a fuse that will only ever blow because of a short circuit in a battery-powered circuit.
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i was basing 15A on what the DVR2 people say for 6v - hasn't blown for me yet.
tho a fair point TT - current may swing around more on an old lucas reg making a higher rating preferable.
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Thanks everyone, based on your comments I think I'll start with 20A but carry some 25A just in case.
cheers
Tim
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I always wire the fuse in the battery earth lead rather than the "live" lead. This still protects all of the circuits and will also blow when I change the battery and accidently touch the live to earth (again), and yes I know the earth terminal should be fitted last but accidents still happen
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wire the fuse in the battery earth lead rather than the "live" lead
it will isolate your battery either way, but not solve other problems, like battery fuses still won't protect the regulator eg from still driving into a headlamp short (like where this thread probably started. (i've added a second fuse between reg and lights/ammeter, just to be sure and sure again).
for safe battery changes remove the ground first from the battery, not the live.
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Surely an electronic regulator has a current limiter? I build my own and always build in a max current limit to protect the dynamo.
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I would avoid upping the fuse rating above the recommendation of the reg maker. If the rating of wire in your harness is less than the fuse rating the wiring could fail before the fuse, which could set the bike on fire.
The thinwall cable used by some of us is rated at 16.6 amps.
My 12 volt A10, using a 6 volt armature, has a 16 amp fuse which is good for a 60/55 watt H4 bulb. Never thought the 12 volt armature offered any advantage given the wiring on it must be thinner than that of the 6 volt type.
As the problem with the electrics has persisted for some time there must be a fundamental electrical problem and if it was my bike, I would completely rewire it and clean and service or replace all the switches. I would also look carefully at the dynamo.
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Dynamo is a 12 volt recent rebuild(last year) reg is new as of a couple of months ago. I shall check each switch and work from there. Surely if the reg was faulty it would always over charge lights on or not???
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Surely if the reg was faulty it would always over charge lights on
who knows how things die? maybe Manor Mike if he's watching.
Intermittent faults are physics reminding us we don't really know much
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Forgot to say without engine running the lights behave normally(for a BSA *smile*)
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There seems to be some new dodgy headlight bulbs about at the moment. If it only happens when the headlamp is on, might be worth checking the fillaments are not vibrating together when the engines running. Does the headlight get brighter before the fuse blows?
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Fixed it. The main light switch some where. It got to the point where just switching it to headlight tripped the fuse, so disconnected the wires cleaned up the contacts rewired and hey presto it all works. Thanks for all the pointers *smile*
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I suspect some wires were touching off around the switch
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glad you got this fixed. interesting how the 'overcharge' fault showed a short due to the wiring. it may be worth checking if the lights should, for your bike, be wired as they are
good persistence! *smile*
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The wiring looks as per diagrams so who knows *conf*
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Back from our holiday trip on Friday, so I have not commented until now.
Glad to hear that all now seems well on the BSA500 machine. This story emphasises the importance of fitting a fuse in the system, and 15 Amp for 6 Volt is what I recommend, and is very unlikely to 'nuisance' blow if all is working correctly.
None of the commercially available electronic regulators aimed at fitting to our kind of bikes incorporate current limiting (as far as I am aware). It is a feature which would rarely come into play with our simple electrical systems. That said we do recommend considering fitting a regulator with current limiting for electric start machines, or if a particularly large battery is fitted. Our DVR3 is then suitable, and costs around half as much again as a DVR2. A small price premium compared to the value of the machines we ride, but for many (perhaps most!) of our customers initial purchase price is a prime consideration, and often electrical details are not really appreciated.
Looking forward to a busy week starting Monday 9 p.m. *eek*
Cheers, Mike
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Congrats also from me on your perseverance to find the issue- I think mine had similar but was the wire to the speedo where it goes through the headlight shell. Being an afterthought running LED's is just thin wire poked through and didn't have a fuse on, but now does....
My wiring is out of ordinary due to bits stuck anywhere, so I have a fuse on each circuit as well as a main one at the battery, so if one pops I know which to look at, but they are various ratings (7.5A - 15A) depending on the load (or what I had at hand- working on that).
I'm still sussing my positive ammeter reading, suspecting the meter or battery, but if it persists and I need ideas will probably find/start a different thread
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Re current limiting regulator. I think it is good idea as even the Lucas mechanical regulator limited the current via the bimetallic spring connected to the regulator adjusting screw. If it's good enough for the Prince of Darkness etc......
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Thanks for mentioning that B-reg, I was wondering if there's any kind of current adjustment on the mechanical regs. (Mine is a aftermarket B107).
Pulled the battery out overnight to give it a bench charge, and give it a bit of a shake-up to free up the air bubbles (did that with a spare one the other week and seems to have succeeded) , and the amp meter behaved itself on the way to work, so will see what happens.
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Re current limiting regulator. I think it is good idea as even the Lucas mechanical regulator limited the current via the bimetallic spring connected to the regulator adjusting screw. If it's good enough for the Prince of Darkness etc......
The bimetallic spring was there to vary the regulator voltage setting with temperature. Trouble is it responds to the local temperature of regulator (subject to load variation), not to the battery temp which might be useful, especially if the voltage control were more precise in general.
The CVC (Compensated Voltage Control) 2 bobbin units did have crude current control by rolling off the voltage when the load current increased. Arguably not the ideal thing to do (as the voltage is reduced just when the maximum voltage is needed, that is with headlight on), but a low cost approach. The 3 bobbin controllers with separate current limit adjustment were used on systems where higher performance was necessary.
The Prince of Darkness stuff comes about due to poor maintenance of the electrical items over a long period, and not in my opinion due to the implementation of the design and technology of the time. But of course decent electronics can do a much more accurate job. The real key to successful regulator design has proved to be to make them robust against all the stresses they will encounter over a long period of use. It is fairly easy to design a basic regulator which functions adequately. There are plenty of DIY circuits available on the www, but I would not want to go far with some of them without breakdown recovery and time on my hands.
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Totally agree. There are some horrendous circuits floating about on the Web. It takes a bit more experience than a quick Google and a trip to Maplins. Also agree about Lucas, one of my bikes is still running a RB107 after 60+ years and operating and regulating perfectly. Not bad when you consider they were made down to a price.
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Much of the "prince of darkness" nonsense started in the US, which is ironic considering the general crap-ness of American car and bike electrics of times past. I think after fifty+ years Lucas stuff can be forgiven for being unreliable given that it either won't have been touched or will have been generally FUBAR'd.
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Congrats also from me on your perseverance to find the issue- I think mine had similar but was the wire to the speedo where it goes through the headlight shell. Being an afterthought running LED's is just thin wire poked through and didn't have a fuse on, but now does....
My wiring is out of ordinary due to bits stuck anywhere, so I have a fuse on each circuit as well as a main one at the battery, so if one pops I know which to look at, but they are various ratings (7.5A - 15A) depending on the load (or what I had at hand- working on that).
I'm still sussing my positive ammeter reading, suspecting the meter or battery, but if it persists and I need ideas will probably find/start a different thread
Thanks all. Used the bike today for work and completely trouble free. It looks like a bunch of wires were pushed against the headlight shell causing a break down on the wire insulation. The problem occurred at the same time I changed the rear lamp causing me to initially look at the wrong end of the bike for a couple of days *sad2*