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Starter relay diode?

Robert Anglin

Well Known Member
This one is for my electrical wizzes out there. Had a starter relay diode go fault on me probably vibration and sharted. Question is both Van's and Spruce have these but they are different venders. It was an ACS one that went fault on us. Witch do you think is more robust and a better unit to put back. Don't want to be with out one for very long. Thanks, Yours, R.E.A. III # 80888
 
not sure about quality variances as these are made in high quantities.

if you have the shrink tube and ring connectors already they can be had 10 for $5 on Amazon and you could make up a few spares. I think any N54xx should work. I used 5408s. Just solder on your wire, etc.
 
Thanks.

Thanks, guys. I had not thought of B&C, but have procured a lot from them down threw time. We have the one that comes with the starters from Kelly. I think it is the same as the one Spruce sells. I wanted to try something a little better if I could as this one has a very small diode in the loop and I was questioning its quality and durability. I think I will call B&C and get a couple coming as I see they have the N5400 in their assembly. If that one only goes another 150 hours we will try the one Van's sells. Thanks as always, Yours, R.E.A. III # 80888
 
The 1N400x are 1 amp diodes; 1N5400x are 3 amp diodes. Either will work fine in that application if installed properly, but the 540x will be a bit more physically 'robust'. If you think vibration killed it (unlikely; stressing the lead to package interface during installation is probably what killed it), you can always squirt a dab of E6000 type adhesive (Shoe Goo, etc) between the device & the contactor case to stabilize it.

The last digit is the voltage rating; likely more important than the current rating for this application, since even the 400x will handle 30 amps forward surge for 5 milliseconds. The 4007 carries a 1,000 volt rating, while the 5408 carries a 1,000 volt rating. (Nothing is ever completely consistent....) If you shop for them, you'll likely find very little price difference between a '01' and an '07/08' in either device. In my old electronics repair business 30+ years ago, we just stocked the highest voltage rating to minimize parts inventory.

Charlie
 
Up-date.

We may have found some idea of what was going south on this one. After taking it off so we could wait for the replacement to get here. I found that I could hold the wire and slightly twist the ring connecter on both ends. Looking at the crimp, it looks like they were not crimped good and tight to begin with.
This is the ACS starter solenoid diode assembly from Spruce, their # 16050-2. It came with our ignition witch from them. I will be checking the ones that are coming from B&C. Thanks for the help, I would like to have put one of the old ford pick-up truck diodes in as those things have always held up to a lot of abuse in the field. Yours, R.E.A. III # 80888
 
Note of addition.

When we got the IN-5400 diodes, we took the one that had failed apart to look close at it. The diode that was in it was stamped IN-4006, a one Amp rating and a third of the size of the new IN-5400. We made the new one up with red and black shrink tube over the wire on both ends then after putting the ring connecters on with a good crimper we put clear rap over the full length from terminal to terminal. I think these new 3 Amp units will be more robust and durable. Thanks for the help. Yours, R.E.A. III # 80888
 
It doesn't matter electrically if you use a 1N4006 or a 1N5400, but the 5400 is more mechanically robust.

After crimping it makes sense to solder the ends as well. Crimp terminals are not designed to be effective on the solid wires, so the soldering helps. To be a total fuss-bucket, use Sn-Pb (tin-lead) solder to minimize terminal corrosion, and clean the flux off with MEk afterwards.

Heat shrink is ok, but it also hides defects.

V
 
Deutsch diodes

If you want something more robust at a slight weight penalty, have a search for Deutsch diodes. These come in 3A, and have a 2 pin Deutsch connector which you can use to run two wires out to your solenoid, rather than mounting the diode on the solenoid itself. You an also get sealed diodes with an automotive QK type connector as well, these are slightly cheaper.

I'll try and get a photo of both today, I have them at work.
 
Diodes

Here is a photo showing the two kinds of Diodes I was talking about - Both are robust, and the Deutsch style one (black) is also mountable using the silver mounting clip.

2vxhv00.jpg
 
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