9 volt battery for jump starting

[Optimistic Paranoid]

Got to thinking about Stargazers dead battery problem, and it got me wondering:

If one has a continuous duty solenoid connecting the engine and house batteries together, and the engine battery goes dead, could you activate the solenoid by clipping a 9 volt transistor type battery with a couple of test clips on it to the two small terminals of the solenoid?  Would it put out enough current long enough for the house battery to start your rig?

 

[highdesertranger]

good question, I don't know the answer. I do know a 9v battery will run an GM HEI distributor but for how long, again I don't know. you could always run a secondary energizer off a switch off the house battery. for sure that would work. either way you would need big cables and a high amp solenoid to get an instant start. if not then you would have to wait a few minutes depending on how dead your starter battery was.

as a side note once I jumped my truck start battery off my 4wheeler I just hooked it up and let the 4 wheeler run for about 1/2 hour then I disconnected the cables and the truck fired right up. highdesertranger

 

[John61CT]

There are many solutions that have self-jumping built in, just throw a switch.

Cheap and easiest solution is jumper cables.

Or carry a little powerpak. They can also bevery handy for carrying lots of USB power or even supplement a laptop when out and about, but if routinely used for that get two and rotate them so one's always fully charged.

 

[tx2sturgis]

Hey, the OP is OP!

Interesting question.

I found some specs online and it MIGHT work.

It might not.

A normal 9v battery can briefly put out about 500ma or so, maybe more for very short periods.

The solenoid coil current appears to be in the .5 to .7 amp range, to HOLD the coil.

Pulling it in, might be a lot higher.

So...it might work.

But if the solenoid coil will not pull in at 9 volts, and needs 12 or so, then you are not going anywhere.

Maybe a pack of 8 AA batteries would do the trick?

 

[SternWake]

Move both big cables of. Solenoid to same stud. Later, Return them

 

[tx2sturgis]

Move both big cables of. Solenoid  to same stud. Later,  Return them

If you have big wrenches handy!

I think OP is thinking of a simple, inexpensive kit for the ladies (or anyone) to carry along in case of starter battery running down.

 

[Trebor English]

Use a jumper cable clamp, just one clamp, to connect the two studs together.  Make sure the other end of the cable doesn't short both batteties to the chassis.

 

[jonsun]

previous owner rigged a wire with a crimped prong to the fuse box on mine and plugged it into an empty acc slot. even if the battery can't start the engine, it can activate the solenoid.

 

[John61CT]

as long as it is wired to ensure the alt is never isolated,

A simple 1/2/B switch could also do the job, load directing just the Starter if you like. Blue Sea makes nice robust high amp ones.

 

[gapper2]

Doubt the 9v battery could supply enough to close the solenoid long enough.  I saw a trick used about 50 years ago.  Dead starter battery in Car 1.  No jumper cables.  Ran small wires from car 2 battery.  Let charge for 30 minutes.  Remove small wire from both cars!  Car 1 had received enough juice to start the car.  I suspect the same trick could be used to short the solenoid for 30 minutes.  Remove the short wire!  Then start your vehicle.

gapper2

 

[Weight]

One or the other battery cable at the solenoid will be at 12 volts. Just a jumper from that terminal to the exciter terminal will close the solenoid. But. Are your battery cables from the house to the start large enough for starter duty? Is your house battery large enough to carry a stone dead starter battery? You may have to disconnect the starter battery long enough to start the engine. Or call road service. You do have road service?

 

[Optimistic Paranoid]

As a couple of you guessed, I was trying to work out the easiest way for the electro-mechanically clueless to solve this problem, a category way too many of our new members seem to fall into. 

For now, I'm thinking one of those lithium ion jump packs is the best we can recommend to them.

As for road service, none of them will leave the public roads to come find you when you are boondocking way back on BLM or Forest Service land, thus it's a non-solution for a lot of our people.

 

[MikeRuth]

You would be better off just keeping say a Lithium Polymer battery available every where these days say in a 3 cell 2200+ah capacity. That would run the solenoid coil for a minimum of 30 minutes. These type batteries will hold there charge with roughly a 1% self discharge per month. They will last approx 3 years.

Draw back, you would need a compatible charger, although they can be had for about $20.00 these days. You will need to add your own terminals to make the connection to the solenoid.
Don't forget to charge it say once every 6 months.

I wired my solenoid to the house bank. the solenoid only draws 1 amp so wiring up to the solenoid does not have to be very large.

Mike R

P.S. So far there was only one time I needed this, forget why but the starting battery was to low to start the van, flipped the switch to activate solenoid, 60 seconds later I started the van.

 

[Spaceman Spiff]

. . . could you activate the solenoid by clipping a 9 volt transistor type battery with a couple of test clips on it to the two small terminals of the solenoid?  Would it put out enough current long enough for the house battery to start your rig?

Short answer: No.  A 9 volt 1604A (alkaline) battery will not close the circuit on my Cole Hersee 24059.

Used a 9 volt battery that tested good, 2 ft, 12 gauge test leads with alligator clips.  Surprisingly the littlefuse web site does not give activation current or voltage range, just says 12 volts.

 -- Spiff

 

[tx2sturgis]

Short answer: No.  A 9 volt 1604A (alkaline) battery will not close the circuit on my Cole Hersee 24059.

You should have been a science teacher!

 

[SternWake]

I like the small jumper wire from house battery side to coil activation trigger stud idea the best. Only one connection to screw up.

Reversing the polarity on a jumpstarter is possible. Such a person much have just as many isues trying to use a 9v battery to close the solenoid too, Which we now know would not work anyway as 9v is not enough to fire the electromagnet, and perhaps on some solenoids it would, but for how long? Long enought to get behing the wheel and try it?

There are multitudes of ways to jump engine battery from house battery, and multiple considerations to each method.

Everyone should have a plan on how to do so in their specific vehicle's system.

Those with the simple solenoid, well either put both wires to same stud, or hook a wire from house battery side to (+) coil trigger stud. It only needs one amp at 12v to close the solenoid. One need not undo any bolts, just strip some insulation off a spare 22 awg or thicker wire, wrap it atound the bigger stud, then the smaller stud, doing their best not to touch grounded metal while doing so.

Once engine starts remove wire, and then don't expect a 15 minute drive is enught to fully charge engine battery like 99% of the driving public does believe

 

[John61CT]

You would be better off just keeping say a Lithium Polymer battery available every where these days say in a 3 cell 2200+ah capacity. That would run the solenoid coil for a minimum of 30 minutes.

A little powerpak is much more generally useful, solves the "vehicle won't start" problem independently of what solution may be in place for combining banks.

Capable of jump-starting any vehicle, powering all your screen devices, built-in flashlight etc,