I am rewiring my starter solenoid (the ignition won't start it any more). I would like to ask anyone if they know the current draw (amps) so that I may use the correct wire size and in-line fuse. 1986 sdl.

Thanks
Dan

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1986 300sdl
1984 300sd
1988 300se
1973 vw thing

This is an imperfect answer but for a DC system it's a place to start.

Measure the resistance.

Current = 12/Resistance

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Very imperfect !! Its an inductive load.

I for a while had a pair of wires running into the car that I touched together to make the starter go on my 124. The solenoid has 2 coils, a pull & a hold. It was not worth the effort to use a fuse. If it dont crank, just disconnect. I only used thin wires, about as thick as the temp gauge wire to the sensor.

Hope that helps.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Sheez.

How much more of a caveat could I say then, 'this is an imperfect answer but a start."

However, since you've started. In a DC circuit whether reluctance or reactance, the maximum current flow will be in the first moment the the voltage is applied.

If his ohm meter is a typical low current device the counter EMF induced by the B field will be minimal and a reasonable, first-order approximation of maximum current flow can be estimated from DC resistance.

Now if it was an AC circuit we'd get ole Nikola Tesla to give us an answer.

It's not a great answer to the OP's question but if no one has the specs it's a starting point.

BTW, depending on your climate, you may wish to put the solenoid in the freezer overnight and measure the cold temp resistance.


PS - Trying to get me back for ladyback aren't you.
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Starter health is important to your diesel.

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'84 300SD sold
124.128

UMMM

Yes. Well, I'm not the OP and you know me, mister I remember freshmen (actually sophomore) physics.

But. I looked at your search string. I did see starter current but not solenoid current.

I also saw that my method of approximating current draw by measuring DC resistance in an inductive load was used in that thread.

So compress, I completely agree that you know a whole much more about this stuff than I but it seems for the moment my suggestiuon of taking a minute (less actually) and measuring resistance is what we've got for now.

I suppose it's also useful just to mention the technique so someone knows how to figure out these questions if they have them in a different situation.

PS - loved the y'all, made me think I was back in the 'land-of-cotton'.'

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If you don't start every thread with "I did a search", then someone will tell you to do one. Which, like you, most people do actually search first. No sense in starting another A/C thread

But anyway, I think you have your answer.. kinda. I would guess it pulls something under 10 amps. The starter itself.... well maybe 100, depending on load.

Goodluck

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08 R320 CDI current

Past
95 E420
87 300D Turbo 5spd
90 300TE
83 300SD
85 300TD
92 400E
85 190D

Inductive loads are tricky. Initial current can be quite high. Starter current of 200 amps, possibly approaching 400 amps are quite possible.

Temperature matter as well.

Then to if it's a slow-blow or a fast-blow fuse will matter.

I'd guess to use a 20 amp for the solenoid but that would be for a fast-blow fuse. I suspect auto fuses are slow-blow.

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There ain't no Guessing when it comes to Electrons...
Alternating Current or Direct Current.'All Measurable.

Well, Mayhaps that's technically incorrect,We've no real Empirical Data on what
Output LIGHTNING (Individual or Otherwise) is capable of.
TOO MUCH DATA to be measured.
(Big, Nasty, Planet Killing BOLTS from the Sky!)

I Know so very little about Electricity that Benjamin Franklin would Scoff
at engaging me as an apprentice sweeper in his shop 175 Years after the fact.

Tesla wouldn't allow me to cut his grass.

There're stats for all MB Starters "Draw" AND if yours is out side the Parameters,Find out Why,Fast!
(Bushings?[No Bearings] Brushes? Etc.,Etc.)

Don't have a Hall Effect Clamp for your DMM ?

The local "Advance" has a Gadget that can Print out the Starter's Draw.

"Ass-u-mation" only leads us down the "Road with No Lights"

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'84 300SD sold
124.128

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I am so befuddled.

Well done.

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DC current is used to measure resistance, Inductance does NOT play a part when DC is involved, except for transients when starting or stopping current. This effect is used and amplified by a Kettering ignition system to produce a large induced voltage.

Back to the topic - use any old multimeter to measure DC resistance, then calculate current draw by V/R.

How's life in Holland?

PS - That's the answer I suggested as well.

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