---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 12/03/25: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:54 AM - Re: Re: resistance in solenoid (Al Fuller) ________________________________ Message 1 _____________________________________ Time: 08:54:00 AM PST US From: Al Fuller Subject: Re: AeroElectric-List: 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 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 > 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 > also available via the Web Forums! > http://forums.matronics.comp; - NEW MATRONICS LIST WIKI - > https://matronics.com/contribution > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.