Darmah voltmeter

[aussie_bevel]

Hey
Can you check the motoplat voltmeter (red box with 3 spade terminals)for its intergrity, if so how <?>
cheers
Paul

[Craig in France]

Hi Paul,

I was kinda hoping that one of the Gurus might answer this, but in the meanwhile, here's a thought:

As I understand it, it's basically a voltage sensitive switch, turning the warning light on and off. Its operating range is below 12.35 and above 15.7 (altho' I bet it's nothing like that accurate!)

So, if you can generate that sort of voltage range, it should be fairly easy to test.

HTH.

Craig

P.s I do know that Tony Brancato groans whenever these things are mentioned ...

[aussie_bevel]

Hey Craig
Thanks for the info. So i'm going to go out on a limb and make the statement that " the GEN light should be lit when above or below those voltages and that the GEN light should be off when the voltage falls between the 2 values"............am i right ?

I imagine you could check (with multimeter) the lower value reasonably easy by running at idle with lights on for example. (drawing more from the battery than the circuit is producing) but to get the higher value
i would have to running down the highway at a fair rate of knots to get a overcharge situation let alone try and take a reading ....ha ha.

Does the fact that if the GEN light comes on at the lower value mean that it will also work when you hit the higher value ?

One last question, does an overchrge situation mean you have a f***ed regulator ? mod hat on (no profanity please) mod hat off

Cheers
paul

[Craig in France]

Hi Paul

So i'm going to go out on a limb and make the statement that "the GEN light should be lit when above or below those voltages and that the GEN light should be off when the voltage falls between the 2 values".......Am I right ?

Yes.

I imagine you could check (with multimeter) the lower value reasonably easy by running at idle with lights on for example. (drawing more from the battery than the circuit is producing) but to get the higher value I would have to running down the highway at a fair rate of knots to get a overcharge situation let alone try and take a reading ....ha ha.

Yup, I reckon you've put your finger on the problem - how to generate the higher voltage in a test situation? I guess you could hook up a 6 volt battery to the bike's own, but I wouldn't like to say whether the resulting 18 volts wouldn't fry the voltmeter ... FWIW, with the light on, the gen light on my SSD needs to see around 3,500 rpm before it goes off. Tony B. told me to ignore it

Does the fact that if the GEN light comes on at the lower value mean that it will also work when you hit the higher value ?

I wouldn't make that assumption ...

One last question, does an overcharge situation mean you have a f***ed regulator ?

I think the short answer is, "Yes".

What exactly is the problem you've got?

[aussie_bevel]

In my best queens english.
My GEN light stays on low or high revs and i'm trying to establish why, thought it might be the voltmeter because it basically switches the GEN light on/off. Apart from that the bike does not have any running problems.

Cheers
Paul

[Craig in France]

Yeh, sounds well possible.

Stick a voltmeter across the battery terminals to check the alternator and regulator are working ok. You're looking for around 12.4 - 12.6 volts with the engine off and then an increase and hold at 14.4 volts or thereabouts at 4,000 rpm (leave lights etc off).

Then go out and ride and ignore the little red light :-)

Ciao

Craig

[aussie_bevel]

Thanks for help Craig
That little red light was just annoying me being on all the time, after 6 yrs rebuilding the old girl i just wanted her just right. Now i'm waiting for a couple of bits from the painter to round out the deal

Cheers
paul

[kiwi47]

I have a gen light problem with my 1982 Darmah.There is a little orange box that controls the Gen light.
It is marked Voltimetro A Lampara 6710603 12V Motoplat Made in Spain and has a simple schematic on it. It grounds the Gen light, and turns it on.
My bike seems to be charging appropriately @13.8 volts. I have two Voltimetro's. When one is installed, the Gen light if off all the time. When the other is installed, the Gen light is on all the time.
The conclusion is they are both defective.
Where can I locate a functioning one? A Google search was fruitless.
Is there a fix for it? I was thinking of reverse engineering them both as I think its a dirt simple switch controlled by something that recognizes 12.8 volts or the like.
Anyone been down this road?
Thanks