Not Charging?

topcatcustom · Post by **topcatcustom** » Mon May 03, 2010 8:50 pm

Hi guys, the engine ran today but alternator didnt charge. It is a Denso from a Honda, the 2 small wires from terminals are marked L and IG, live and ignition. Am I right in thinking that the ignition one goes to the dash or should it be the live?

In my landy one goes to the dash light, the other side of the light goes to ignition live, after a little blip of the throttle the light goes out and it starts to charge, should be the same with the mx5 but I dont think there is a dash battery light! Can pop one in easily enough which might be easier than messing around with the existing wiring..?

JSF55 · Post by **JSF55** » Mon May 03, 2010 9:31 pm

i kept this handy

http://westfield-world.com/daihatsu_alternator.html

topcatcustom · Post by **topcatcustom** » Tue May 04, 2010 7:56 am

Excellent thanks, I'll just chop the ignition wire and put a light bulb in there under the dash, a voltmeter would be handy too but dont want to keep sticking gauges in!!!

DaveEFI · Post by **DaveEFI** » Tue May 04, 2010 9:01 am

topcatproduction wrote:Excellent thanks, I'll just chop the ignition wire and put a light bulb in there under the dash, a voltmeter would be handy too but dont want to keep sticking gauges in!!!

Maplin used to do a kit which measured the voltage across the battery earth strap, and drove either a centre zero meter or a tri-colour LED. Showed red for discharge, amber normal, green charge. Adjustable.
Easy to find space for an LED.

Of course Maplin haven't made their own kits for years, but I have the construction details. And recently made up some PCBs using the original as a guide, since I needed a second one. All the components are still easily available. The PCB measures about 50 x 70 mm so is easy to conceal.
Haven't worked out the cost of a kit - but like all these things will be a lot more expensive than a ready made Chinese unit off Ebay - if such a device exists.

topcatcustom · Post by **topcatcustom** » Tue May 04, 2010 9:30 am

Sounds interesting, so a green for say 12-14v, and another colour either side?

DaveEFI · Post by **DaveEFI** » Tue May 04, 2010 10:26 am

topcatproduction wrote:Sounds interesting, so a green for say 12-14v, and another colour either side?

Since it can also drive a centre zero meter, it sort of fades between the colours rather than being hard on. But with everything OK spends most of its time on amber. Doesn't work on battery voltage, but the current flowing in the earth strap. Cunning, really. Gives instant notice of the alternator either not charging properly, or overcharging.

topcatcustom · Post by **topcatcustom** » Sun May 09, 2010 2:32 pm

I found a small 3w lamp to use as a charge warning light and small volt meter amongst my toot, wired them into the dash in a spare switch hole, voltmeter works fine- however the lamp does not light up when ignition is on. One side is connected to switched live, the other goes to the alternator, only 2 pins are used on the alt (minus the big output) and have tried them both but it will not light up. I know it works as if I touch the wire that attaches to the alt to ground it lights up. I took the alternator to a specialist to check it before I used it and it worked perfectly!

The Denso alternato has 4 pins in a round plug- the 2 I use are labeled L and IG, one of the others it for ecu input and cant remember the other but sure we didn't need it!

Migwell · Post by **Migwell** » Tue May 11, 2010 5:35 pm

If you connected it incorrest 1st time you may have blown a diode inside, just a thought.

Cant help with connections, my alternator only has main battery cable and wire to dash charge bulb, thats it.