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1. 08:54 AM - Re: Re: resistance in solenoid (Al Fuller)
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| Subject: | Re: resistance in solenoid |
In the original post, the device in question was described as a
'continuous' solenoid.
Is that relevant, or am I just being pedantic?
________________
Sent from my phone
Best Regards,
Al Fuller
On Mon, Dec 1, 2025, 8:41=AFPM Jeff Luckey <jluckey@pacbell.net> wrot
e:
> *What we know:*
> 1. remote diagnosis is difficult at best ;)
> 2. not having a schematic makes that worse
> 3. the resting voltage of an EarthX is about 13.2 V
>
>
> *Questions:*
> 1. have you put the voltmeter across the input and output studs of the
> solenoid? With what you are describing, engine off, that reading should
be
> 0.6 volts (13.2 in - 12.6 out = 0.6 volts)
>
> 2. does cranking current flow thru this solenoid?
>
> 3. has cranking seemed "soft" lately?
>
> 3. is there an errant diode somewhere in the circuit - just a WAG, but 0.
6
> v is about the drop of a silicon diode - again, just making this up ;)
>
>
> *Things you could try:*
> Starting with simple, no-disassembly-required tests
> 1. put the voltmeter across the input and output studs with everything of
f
> - what's that voltage?
> 2. turn on the master (but don't run the engine) - based on your
> description, should read 0.6v
> 3. start turning on high-current stuff like pitot heat, landing lights,
> etc - IF there is some weird resistance thru the main contacts, the volta
ge
> drop should increase as you add load. If you have an ammeter, write down
> amps, what equipment is turned on, and voltage drop across solenoid.
>
> You could have a high-resistance thru the contactor, but if starting is
> good, it kinda rules that out.
>
> Also, the resistance we are talking about would be well below 1 ohm and
> typical multi-meters cannot accurately measure resistances that low. Jus
t
> as JoeG mentioned, you will have to use another technique to test that
> hypothesis. #3 in Things to Try might shed some light on this.
>
> Happy (gremlin) Hunting,
>
> -Jeff
>
> On Monday, December 1, 2025 at 03:50:03 PM PST, bobnoffs <icubob@gmail.co
m>
> wrote:
>
>
>
> voltage at eis is 12.6 with engine off. it is 14.3 with engine running. i
> have checked all numbers with eis voltage, handheld voltmeter and panel
> mounted voltmeter i just bought and they are all aligned.. measured volta
ge
> is 13.2 at battery side of solenoid and 12.6 on the load side, engine off
.
> alternator is charging fine and battery voltage is fine but after the
> solenoid it drops to 12.6. all this is with an earthx, not lead acid.
> i haven't actually measured resistance in the solenoid but it seems to be
> pointing at that, what else could it be?
> bob
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=516709#516709
>
>
> - The AeroElectric-List Email Forum -
> http://www.matronics.com/Navigator?AeroElectric-List<= Same great conte
nt
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