Originally Posted by IcePack
Dave they look great. Have you had any problems/indications with the INRUSH current you get when switching LED lights on, thinking of that PCB.
I had trouble with a light timer. Granted for outside lights, caused by the inrush current. Hence my wondering. Info Here

No Inrush issues.

I also note the above paper seems to be referring to a 240/110v AC mains wiring system in a house, so I'm not sure how relevant it is in an automotive 12v DC situation? I certainly ran LED H4s in my TVR for years and never suffered any such inrush issues.

One thing I can confirm is the Marchal LEDs have massively lowered the load on Morgan's embedded aux lighting circuit that’s protected by fuse 12, to be sure on this I have multiplied the total bulb Wattage on the circuit and carefully logged my battery voltages too using my EMU Black ECU software that confirms the alternator regulates perfectly between 13.4v - 13.7v.

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There is dip to 9.2v under cranking when starting the engine which then spikes momentarily to 14.78v, but this is perfectly normal and to be expected, I should also point out the whole dip & spike episode spans less than a second in time before the situation returns to the well regulated 13.7v.

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Based on my calculations, and now supported by real world testing the 5a fuse 12 I'm running has proved itself to be perfectly sized. However, given that the dip & spike on starting is where I'm most likely to experience an issue I repeated a number of consecutive cranking tests with the Marchals left on, and I'm pleased to confirm all was fine thumbs

As the above photos show, the Marchal LEDs do give off a light that's more on the amber side of yellow, I'm currently on the fence regarding this hue as my headlights are a nice vintage French yellow and I had originally hoped to achieve a match with the Marchals, but I accept you can overthink these things and afterall amber is period correct as it was found on Wipac Grey Nights and Raydyots if people can remember those lamps?

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When all is said and done and now I know how delicate and problematic the PCB dash module is, I have to say if I had my time again I would have simply used the separate aux lights loom (with relay & dedicated fuse) I purchased specifically for the Marchal fog light installation. However, the new Marchal LEDs pull so much less current I'm confident a relay is no longer needed and my PCB is now perfectly safe.