Charging problem

[tiggy]

Hi, the last issue to complete on a long term restoration of a '58 A10 running standard 6v positive earth lucas system. I have left this to the end as I have had a few goes at it without success but now need to hopefully get to the bottom of it with some advice.
Story so far:
Original dynamo completely rebuilt by a specialist and sent back to be re-tested. Definitely putting out a charge.
New wiring loom, circuit/connections tested numerous times, lost count but could be making the same mistake each time!
New regulator- wassel tried  first. I guessed this to be the problem so changed it for a new DVR2 regulator. Still not showing a positive reading or cancelling out the drain on the ammeter. i.e. -4 showing with lights on and does not move when the engine is fired up.
New lucas ammeter. Only shows negative reading.
I have put a multimeter on the terminal of the ammeter that the "A" (F,A,D,E.)wire goes to and get a voltage reading, with the engine running, but nothing from the other terminal.
Is the charge going to one terminal and being lost in the ammeter?
Any ideas of any tests I can do on the the "new" lucas ammeter or any other recommended tests?
Any thoughts gratefully received as I have completely run out of ideas.
Thanks

[Triton Thrasher]

The ammeter should have almost nil resistance across its two terminals, so the voltage should read the same on each terminal.

Measure the resistance from one ammeter terminal to the other, with nothing else connected to the ammeter.  Ammeter can fail and go open circuit. That gives it infinite resistance.

[Rgs-Bill]

Try taking the  (make sure it is fused)    A- wire off the ammeter and run directly to the negative side of battery,  (use a suitable jumper wire if needed)(make sure of good ground) and start the bike and see if your digital meter is giving you readings.  DVR-2 regulators have wrong way round hook up protection supposedly, but it is possible the DVR-2 is the culprit. And if you get good readings, then check the ammeter like previous person said, and make sure you did not have wrong way around on the ammeter the first time around.

[tiggy]

Thanks for the replies. Reading across the terminals of the ammeter when it is isolated is 00.1 OHMS.
Previously tried reversing the wires to the ammeter and got +4 instead of -4 when lights on and still nothing the other side with the engine running.
I haven't tried running a wire from the "A' straight to the negative battery terminal but will give it a go and respond in a day or two.
Cheers

[duTch]

 While you're at it, maybe connect the multi-meter 'amps' function in line and see what it says...?

 Also if it still doesn't work, yo could try reconnecting the mechanical reg., and leave the cover off as per a recent similar topic.

[trevinoz]

Tiggy,
 You should have a voltage at "A" as it is connected directly to the battery via the ammeter.
"D" is the terminal which should have the generator output voltage with the engine running.
Do the generator test with the regulator disconnected, bridge the "D" & "F" terminals and see what is there and what polarity.

Trev.

[duTch]

 Maybe needs re-polarizing?

[BSA_54A10]

And just to make sure.
If the battery is fully charged the generator out put will be 0 or very near to it.
That is what the regulator is there to do, match supply to demand.
I oft have owners complaining that their charging system is not working because the ammeter shows 0 when they start their bike which had been sittng for months with a battery tender attached.

[tiggy]

Lots of things to try out thanks, but first a straight forward question for those of you lucky enough to have a charging system that works as it should.
What ammeter reading do you get with lights on, engine running, and a fully charged battery? Should the needle cancel out back to zero or stay negative until the battery drains a little?
I am seeing -4, the bike is only run for a couple of minutes to avoid overheating as it is off the road.
Cheers.
p.s. looked at the old mechanical regulator that came with the bike. Don't know if it works as last on the bike before the dynamo was rebuilt. Looks good inside but the outer case is chrome not black as most you see and knocked about a bit. Looks like it was mounted outside the tool box. Date stamped 5-54.

[Triton Thrasher]

With engine idling, ammeter should read zero.

Switch on the headlight, still at idle and the ammeter should show a substantial discharge.

Rev it up from idle, still with headlight on and the ammeter reading should climb to zero (if the  battery is fully charged) or go past zero into the "charge" side (if the battery is low).

A "charge" indication, while you ride the bike, will eventually fall to zero or near zero, as the battery becomes charged.

That's what an ammeter does.

[Greybeard]

tiggy,
My ammeter shows a slight positive charge with headlight on. I also have a multi-colour charge indicator LED device mounted to show through the edge of the transparent ammeter case and that shows green when riding with lights on so confirming the charging state. I have a new battery that has not been allowed to fully discharge yet and a good dynamo.

[duTch]

 The other day I picked up a used -8 < 0> +8 Ammeter at a local swap, so the first thing I did was dissect it to see why it might work , but it also need a bit of an internal clean anyway so I'm off the hook.

 Much as I like the one I've been using, it's a +/-30A so not so ideal, but this one's a clear plastic one, so I wired two LED's in series (red + green), and placed them how I guess GB did so they shine through the side, seems to work so far, but haven't road tested it yet. It's not a charge indicator like his, but I put the red on the discharge side, and green...guess where   .
 Theory is, if the needle glows red it's discharging, if it glows green= charging half red/green with lights on = all good

Pic 1 Placement of LED's (held in place with a slash out of a plastic drink bottle )
 "   2 Discharge City+tail light (both LED's)  ~ 0.5 A
 "   3       "       35/35W Head+Tail+City     ~ 7 A

[Greybeard]

...I wired two LED's in series (red + green), and placed them how I guess GB did so they shine through the side, seems to work so far, but haven't road tested it yet. It's not a charge indicator like his, but I put the red on the discharge side, and green...guess where...

Great! Seems to work. Bit bright maybe. I guess you can increase the resistor values to make them dimmer.
The little gizmo I used was not very expensive and very compact but I admire your ingenuity.

[duTch]

 

Great! Seems to work. Bit bright maybe. I guess you can increase the resistor values to make them dimmer.
The little gizmo I used was not very expensive and very compact but I admire your ingenuity.

 Thanks GB; it seems bright, but I'm working on the principle of map-reading lights being red, and supposedly less disturbing and hoping green may be same. Also those bright spots are pin-holes in the tin that I'll be motivated into patching .
 No resistors- hard wired straight in (+ve) to keeper spring nut on back of the switch (-ve) into earth loom, but I'll see how it shapes up.
  I looked at your gizmo, enticing but exchange rate plus postage didn't excite me .

 Another reason for adding them in is so I'll hopefully see it and remember to turn the lights off (or should I call them 'darkness's') when I pull up when out and about

[chaterlea25]

Hi,

No resistors- hard wired straight in (+ve) to keeper spring nut on back of the switch (-ve) into earth loom, but I'll see how it shapes up.

 

They wont last long like that 

They are diodes not bulbs so need resistors to limit the current through them

John