Starter solenoid power

[terrybullwon]

Can any one confirm that the wake up for the solenoid is 30amp?

Cheers James

[johne]

What do you mean by wake up? Peak inrush current for the solenoid will certainly be high and maybe higher than 30 amps momentarily but the hold-in current is probably more like 2 or 3 amps - that said I've never measured it.

John

[terrybullwon]

What do you mean by wake up? Peak inrush current for the solenoid will certainly be high and maybe higher than 30 amps momentarily but the hold-in current is probably more like 2 or 3 amps - that said I've never measured it.

John

Switch feed to the starter not the battery power need to crank the engine

[johne]

That's what I'm on about, switched supply to the solenoid that comes through the ignition switch.

John

[terrybullwon]

That's what I'm on about, switched supply to the solenoid that comes through the ignition switch.

John

thats what i was talking about

Is it fused some where on the top fuse box on the OEM system?

[johne]

As far as I can tell from my wiring diagrams, it's unfused as is the supply feed to the ignition switch as well.

John

[terrybullwon]

Um.... That's a pickle !

[johne]

Why so?

[terrybullwon]

Why so?

I am using a custom loom for the whole car. Going to need a better push button switch

[johne]

I'd keep your push button switch and use it to activate a standard 30 or 40 amp 12volt automotive relay (£2.19 from Maplin) and then use this relay to switch the current into the starter motor solenoid.

It also give you a convenient way to incorporate any security features such as a concealed isolator or an imobilisor.

John

[S2central.net]

Totally agreed with johne on that - tis the normal practice and saves you sourcing a silly 20-30Amp switch to kick the solenoid.

Pull the relay out for extra security too - nudge nudge !

[terrybullwon]

Cheers Guys,

I hate electrics! So time consuming!

The kit I have came with a 40amp starter switch, it works fine to run the starter solidenoid at the minute but I wanted to know how it was done OEM

Cheers James

[S2central.net]

Well you are OK then - but I still say putting a relay in the current path is nice feature to integrate with security - as per factory on most B3/B4 machines anyway.