15v solenoid

[firefighter_2000]

Came across a big solenoid in my pile of junk. Turns out it's a 15v 200amp continuous duty/600 inrush. Had initially planned to use it to isolate the power wire going to my booster cable plug. Did a bit of Google research and looks like some RVs use them to isolate batteries. Can anyone explain how it might work or how it might work for my application?


Thanks!


Craig

 

[tvsjr]

So are you trying to isolate two batteries/battery banks?

 

[firefighter_2000]

Was actually trying to use it to turn the jumper cable plug on the front bumper on & off. I have an anderson plug on the front bumper for plugging my cables into. That way in the event of a crash or something, the cables wouldn't be hot all the time.

 

[wilsonbr90]

Could be done. Dont know how much current it could handle In short bursts. Your better off with a battery on off switch. When jumpstarting you dont use too much current until they attempt to start where you could see upwards of 1000amps. If you say it can handle 600 intermittently it may be fine for years. Its not going to burn down your vehichle but it will eventually get hot and burn out especially with a stubborn start like a diesel.

 

[tvsjr]

For your application, you would simply put it in the positive wire between the battery and the jump connector. However, as wilsonbr90 points out, you may not have quite enough solenoid to get the job done. 600A inrush means for a few fractions of a second when a circuit is initially connected, not for the 30-60 seconds that might be required to crank a diesel over. Even your average F350 will pull 600-1000A to crank and operate the glow plugs. A typical vehicle may even exceed 200A from time to time.

It's not likely to fail catastrophically and cause a fire, but it could arc over and eventually fuse the solenoid, etc.

 

[firefighter_2000]

Thanks for the advice guys. That never even occurred to me. I've located a 500 amp continuous, 2500 amp intermittent (for up to 30 seconds) that I'm going to try. I would do the battery cut off switch, but I want to be able to activate the solenoid via dash switch.


Thanks!


Craig

 

[tvsjr]

That should be sufficiently sized.

 

[firefighter_2000]

I stand corrected. It's 500 amps continuous, 1800 amps for 20 seconds, 4000 amps for 1 second.


It has a diode between the 86 & 85 posts. Can anyone explain why it's set up that way?


Here she is:

 

[Kd8bao]

I like that idea, I am putting a set of those jumpers on my truck. I just put a 225 amp continuous duty solenoid in for my accessories. Something was draining while vehicle was off. But I like the crash protection.

 

[firefighter_2000]

Here's the link to the soldnoid I bought. It's only 40 bucks.


http://pages.ebay.com/link/?nav=item.view&alt=web&id=191321165705

 

[RecElect]

The diode is there to suppress a high voltage spike that occurs when the coil for the solenoid is released. It drains that shock to ground instead of into your circuit. It is pretty much a must have on solenoids and a recommended practice on relays.

Normally when you hook up a solenoid it doesn't matter which terminal you hook your signal wire to, power to 86 and ground to 85, or vise versa, however because this has a diode it makes the solenoid polarity sensitive, in the sense that you must put power on the cathode side of the diode otherwise you would have a direct path to ground.

However, looking at this solenoid, it looks like it has a Zener diode going both ways (which honestly I have never seen before and we see ALOT of stuff go through our shop) and that to me makes it non-polarity sensitive again, while still giving the benefits and protection of a diode suppressed coil.

That being said, no matter what, you should diode suppress any solenoid you put in if it doesn't come with it. That shock can damage leds, solid state switches, etc. we had all sort of problems with a truck that had a tank level gauge on it. Every time we turned the truck on and off we would blow out and led on the gauge. We replaced that gauge 3 times before we finally found an unsuppressed solenoid that was causing the issue. Took a .03 diode, stuck it between 86 and 85, and no more blowing out the tank level gauge.

 

[firefighter_2000]

Mounted the solenoid to the rear of my passenger battery box... Got it all wired in. Flip the switch and it comes to life!