10 replies to this topic

[paulrockliffe]

I no longer have a filament bulb, so I believe the circuit needs a resistor adding so the Alternator will charge the battery.

Does this go in parallel or in series with the led bulb and what resistance should I use, any ideas?

[Spider]

I use a 68 ohm, 5 watt resistor, but any value up to 220 ohms will work.

 

You can use a lower watter one, but I prefer to go to this higher wattage type as the surface temperature will be lower.

[ACDodd]

Indeed 68ohm works perfectly, as does using a bigger wattage as suggested by Moke spider to dissipate the heat better.

Ac

[Bobbins]

In series or parallel?

[Ethel]

Parallel

[paulrockliffe]

Nice one, thanks. It'll work in series won't it, with a different resistance?

I did learn this at uni, but can't remember now/missed the lectures.

[ACDodd]

No it must be connected in parallel with the led.

Ac

[paulrockliffe]

Cool, just waiting for the resistors to arrive now.....

[paulrockliffe]

After being messed about by China, I finally have my resistors!  While I'm plumbing one in, can someone point me in the direction of a quick test to check the alternator is charging?

 

Ta

[Spider]

Measure the battery voltage with the engine running at around 1200 RPM of more. should be circa 14.0 - 14.2V.

[paulrockliffe]

Thanks, I fitted the resistor, but I need to get the rest of the dash in before I plug the light in, so I'll test it when I get sorted.....