Dual Battery - Ford-type starter solenoid

[OldPaj]

Hi

Whilst trawling through Supercheap I came across a Ford-Type Starter Solenoid for $13 and bought it to use in a VERY cheap dual battery system. Got home, searched the internet for specs and found this
http://www.4wdaction.com.au/reviews/tips/acid-hit-02.php

This site describes the use of this solenoid in dual battery systems. However, I also found lots of sites discussing the use of starter solenoids and am now worried that this units will not last long if used continuously.

Any advice ?

Cheers

[toy yoda]

You are right with the starter solonoid type with continous use, they may have a high amperage but for short bursts....

BUT whilst your in supercheap they have a 200a continous journey solonoid,,( the silver can) for under $30.00 these are perfect for dual batteries, they are like a winch solonoid too.....there is 2 ways to wire them up either as an isolator on the charge circuit to 2nd battery or as an isolator betwwen the 2 batteries using starter cable

these solonoids are great, they are NOT a smart type that directs charge to either battery they simply allow both batteries to recieve charge whilst ignition is active...they will withstand water , dust and vibrations... Ive been using them on customers vehicles for many years and the old man for many more years before that!!!

[OldPaj]

Hi


Any idea why the 4WD Monthly article suggested using the starter solenoid?

I have spent quite a bit of time at the wreckers lately (looking for bits and pieces to tart up the old Pajero for a Simpson Desert trip next Winter) and out of maybe 8 old trucks that had dual battery trays, at least 6 of them had the unbranded aluminium canister solenoids.

From some articles I have read, these are simply hooked up to a 12V source that is active when the ignition is on. However, I also read somewhere on the internet, that these can be hooked up to a trigger supply that provides current only when the alternator starts to output current ie not during initial engine starting, but once engine speed is sufficient to trigger the regulator to pass current to the battery. This sounds like a good situation as the drained auxiliary will not be connected to the starter during starting. Any idea what this connection is? Is it the charging wire to the starter battery?

Cheers

[OldPaj]

Another question......
Does anyone know what the voltage drop across the cheap solenoid contacts is?

Cheers

[toy yoda]

firstly those unbranded alluminium canisters sound like the one im talking about..
with using the alternator as a switching mechanism...there is the charge output ( the 10mm nut) which i use....the other wire is a field wire and it is powered when ignition is on ( dash light) but as soon as the regulator his top gear ( 13.5 ish Volt) then the power to that wire is gone!

90% of the systems ive set up are a charge circuit only! O o o O
1 2 3 4
terminal 1...from solonoid to dual battery ( via fuse link)
terminal 2...to earth
terminla 3...to a (+) ignition supply
terminla 4... to the alternator charge output

this means that the batteries are isolated when ignition is off but the main battery is solely responsible for starting.....
..I earth the aux batt to both body and chassis with starter cable & then i run a starter cable between the (+) terminals on each battery with a isolator key switch ( big red ones) this stays off and doesnt serve any purpose but in the even or a flat cranking battery ..turn key and instant jumper lead!!

[toy yoda]

i have run the meter across the terminals on every system ive fitted..obviously to watch the solonoid is switching when (+) activated......but i cant recall the drop....it would be bloooody marginal or it would have concerned me at the time!!! i guess i could check tomorrow if you need to!

[SAT44N]

I just have my solenoid running off a rocker switch on the dash. Most of the time its left on but I like having the full manual control of it.
Was very handy the day my main battery died and it was just enough to crank the truck over.

[sudso]

My dbs is a parallel system and has an Ingram constant duty solenoid. It would have to be at least 6 years old. My batteries are isolated from each other when the ignition is off but connected when on acc's, on, and starting.

[dultim8]

what size and type of fuse should be used when setting this up.
i have all mine connected at the moment with no fuse.
what is the purpose of the fuse in this link?