Back to the 6volt alternater dash light

Unknown

Just in case somebody did'nt get it all done on the 6v system. And thanks to Geoff for his expert advice. First thing I found was the people selling the redone 6v alt don't always advertise it correctly. To determine if you have a self exciteing alt remove the wire from the alt, start the engine but DON"T rev it. With a multimeter you will have maybe 1 to 2 volts from the alt terminal to a ground,NOT TO BATTERY.. Now rev the engine with the wire still off and if it is self exciteing you will have 7-8 volts from alt terminal to a ground. NOT TO BATTERY! Wire according to Geoff's instructions and it will work. I'm useing a blocking diode normally used on a wind generater,lots available on the net.just get into blocking diodes or wind gens to find one. My relay is a Bosch 12v normally closed,again availeable all over the net, but it switches to open with as little as 6v or less and may be even better than a 6v for this use as it will close at a higher voltage than the 6v relay. Geoff might have a good answer to that. Thanks again Geoff for hanging in there untill we had one actually working

Geoff

I'll publish this wiring diagram in a future article in the W.T.N. There are two ways of doing it, either by using two relays and a Zener, or one relay and a diode.

Geoff.

Unknown

Thanks Geoff, You might mention that if they don't allready have the alt. the one wire SELF EXCITEING is the easeist and they should spec that when buying. I found that in locateing the proper ZENER diode for an externally excited alt. they have numerous differant values and the wrong one won't work,and most of the time what is on the net is left over parts from mfg. being resold by people who know nothing about what they have. Real hassle there. The wind gen blocking diode and 12v n/c relay with a spike arrester for flashback built in are easy to find. Also the instructions with my alt said a wire from the bat, excited it . WRONG INFO. It kicks in like I said and puts out over 8v with no wire from the bat in the circuit ! Put the bat in and it comes down to 7.6v. What's your opinion on the 12v relay, a 6v would have to drop to about 3v before it switched back to closed,bat too low to crank engine by then.

Geoff

The blocking diode will prevent the relay from energising if the alternator stops charging. No current can flow from the battery to the alternator, only from the alternator to the battery. Hence once the alternator stops charging, the relay will drop, and the light will show. A 12 volt relay will be a little more sensitive perhaps, but should work okay.

Unknown

37 Terraplane#2 wrote:

Thanks Geoff, You might mention that if they don't allready have the alt. the one wire SELF EXCITEING is the easeist and they should spec that when buying. I found that in locateing the proper ZENER diode for an externally excited alt. they have numerous differant values and the wrong one won't work,and most of the time what is on the net is left over parts from mfg. being resold by people who know nothing about what they have. Real hassle there. The wind gen blocking diode and 12v n/c relay with a spike arrester for flashback built in are easy to find. Also the instructions with my alt said a wire from the bat, excited it . WRONG INFO. It kicks in like I said and puts out over 8v with no wire from the bat in the circuit ! Put the bat in and it comes down to 7.6v. What's your opinion on the 12v relay, a 6v would have to drop to about 3v before it switched back to closed,bat too low to crank engine by then.

Question? If the self exiciting Alt. is the easeist to use , Why do you need the diodes and the relay. 2 wire doesn't need all this , Only one wire to Batt and 1 wire to idiot light does it all. You DO NOT EITHER NEED OR USE A DIODE WITH THE EXTERNALLY EXCITED ALT. Nuff said....

Unknown

Think I'll just follow Geoff's advice,NUFF SAID

Geoff

I am not advocating either type of alternator. I still have the original generator and regulator on my cars. What I was doing was providing a way to use a single wire alternator, and still be able to use the warning light. I agree that if two-wire alternator has the facility to turn the light out, then by all means, go this way. But if you already have a single wire alternator, there is a cheap and effective to use it, and know that it is working. Incidentally, I have an ammeter fitted to all my cars, and this of course would obviate the need for a warning light. An ammeter gives you a direct reading of exactly what is going on in the charging system. However, a warning light is far more effective in telling you right away that something has gone wrong.

Geoff.

Unknown

Good answer Geoff and I agree 100%. There is not always one and one only way to get things done. What happened to me was all my gauges,sending units are wired in a daisy chain and the light hooked up was makeing other things go goofy,why I don't know except that small amts of feedover can cause problems and be hard to find.. So I put in a volt meter, everything worked fine, I just did'nt like the looks of it hanging under my dash. The relay , diode system gets it gone and the light working. The whole point is if it works do it no matter how how you get it done.