Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / August 2007
How to make a mobile jump-box?
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Matt - 14 Aug 2007 02:40 GMT I am a master auto technician, and I am seeking the opinion/advice of other master technicians who work in the field.
We've all come to know (and love, in my opinion) battery jump-boxes in the last 10 years or so. The days of jumper-cables are pretty much over.
What would it take to make a jump-box part of an automobile?
Let me explain... a jump box can easily be connected to a battery, and even left there if desired. A basic parallel circuit. It would then take a charge from the alternator right along with the regular car battery. Trouble is, if something were left on such as an interior light, the jump-box would be drained right along with the car's battery. Not the result I am looking for.
What device might be created that would allow a jump-box to be wired into a vehicle were it would be charged during vehicle operation, but not drained when the vehicle was turned off?
Example: vehicle drives from point A to point B. The battery and the jump-box are charged along the way. Owner shuts the car off but accidentally leaves the dome-light on, thus killing the battery.
How might it be possible for the jump-box to receive the alternator's charge but not be drained by the forgotten dome-light?
Some sort of magnetic switch (a solenoid, perhaps) comes to my mind, but how that configuration might be alludes me.
It has occured to me that constant charging of a battery (jump-box) might not be a good thing, but I have also observed that a vehicle can charge a battery for dozens of hours without said battery exploding. I have also seen jump-boxes be left on a plug-in charger for weeks (even a month) with no apparent negative effect.
The final product I seek: An jump-box stored in perhaps the trunk or elsewhere that is kept charged by the alternator during vehicle operation, but would not be drained if a device were accidentally left on after the engine was shut off. Should the vehicle have a dead battery, just take that jump-box out of the trunk and get going.
Is it possible? It must be. It has to just be a matter of power here, switch there, relay here, jump-box there...
Calling on the best of the business, I know you're out there!
Matt
Nate Nagel - 14 Aug 2007 02:53 GMT > I am a master auto technician, and I am seeking the opinion/advice of > other master technicians who work in the field. [quoted text clipped - 44 lines] > > Matt I believe that you can buy a box that will cut off your battery before it drains, thus leaving enough juice for one attempt at starting before it goes dead flat. I think you pop the hood and press a button to reset it before starting or something like that.
The other option would be an extra full sized battery with one of those electronic isolators like RV's use, with a switch to cut over the auxiliary battery when the primary goes dead. Space and weight are the downsides of that setup.
nate
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Matt - 14 Aug 2007 03:11 GMT "Electronic isolator" is what I am searching for. I can take care of space, weight, long wires, etc... anyone out there who might be able to elaborate? I think it should be possible to connect a jumper-box *that could be used on any vehicle*.
Think how the towing business could profit!
Nate Nagel - 14 Aug 2007 03:46 GMT > "Electronic isolator" is what I am searching for. I can take care of > space, weight, long wires, etc... anyone out there who might be able > to elaborate? I think it should be possible to connect a jumper-box > *that could be used on any vehicle*. > > Think how the towing business could profit! They already make mobile jump-starters... and they do work on pretty much any vehicle; you can indeed start a 6V vehicle from a 12V battery if you a) know what you're doing and pay attention to polarity (the vast majority of 6V vehicles were positive ground) and b) make sure that *ALL* accessories are turned off until the 12V battery is removed.
nate
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Don Bruder - 14 Aug 2007 04:57 GMT > "Electronic isolator" is what I am searching for. I can take care of > space, weight, long wires, etc... anyone out there who might be able > to elaborate? I think it should be possible to connect a jumper-box > *that could be used on any vehicle*. > > Think how the towing business could profit! All the tow-trucks I've seen lately have had simple plug-in cable connections at the bumper. Grab the cables, cram 'em in the socket, attach to "jumpee", proceed.
Why do they want to dink around with another battery?
 Signature Don Bruder - dakidd@sonic.net - If your "From:" address isn't on my whitelist, or the subject of the message doesn't contain the exact text "PopperAndShadow" somewhere, any message sent to this address will go in the garbage without my ever knowing it arrived. Sorry... <http://www.sonic.net/~dakidd> for more info
Matt - 15 Aug 2007 02:00 GMT > In article <1187057506.185334.165...@g4g2000hsf.googlegroups.com>, > [quoted text clipped - 16 lines] > somewhere, any message sent to this address will go in the garbage without my > ever knowing it arrived. Sorry... <http://www.sonic.net/~dakidd> for more info I am just trying to keep it light. If they already have it, then fine. I don't work on tow trucks, so maybe I could gain from what people have already figured out. That's the point of this post... *how* does it work.
Bob M. - 16 Aug 2007 06:15 GMT >> In article <1187057506.185334.165...@g4g2000hsf.googlegroups.com>, >> [quoted text clipped - 25 lines] > have already figured out. That's the point of this post... *how* does > it work. These things are all over. You can buy a self-contained unit (battery, 2 foot long cables and an AC plug for charging the battery) at <insert car parts place here>, *-Mart, and so on for not much. Includes a handle too! Weighs 5-10 pounds; cart not necessary.
Some have other features like a flashlight & cigarette lighter socket.
Ad absurdum per aspera - 15 Aug 2007 20:31 GMT > Think how the towing business could profit! Huh. I'd guess that increasing the redundancy of vehicles' starting power, and the self-reliance of drivers, would mean *less* business for them. Of course, in big cities that might be a good thing, weeding out the silly little "one minute's worth of problem at the end of half an hour's trip" calls and letting them work on the backlog of accident and serious failures.
One might envision a slightly evolved version of the now familiar and pretty cheap jump-start box that can trickle-charge off the car's circuit (suitably isolated) and sit in a well in the engine compartment -- sounds like what you're talking about. However, that's space and weight that a lot of people begrudge in the already tight engine compartment; and the environmental factors in there are not kind.
Several years ago there was a brand of car battery that had a small auxiliary built in. After a few minutes of coulda-shoulda-woulda regarding the headlight switch, you opened the hood, flipped a lever or something, and (unless the car was really balky or the system wasn't working properly) started off this reserve of power. I haven't seen those in a long time, though, and seem to recall them as having a premium price, which might have been the reason.
> The days of jumper-cables are pretty much over. I see them in use quite often, and have them in every vehicle. The days of people willing to pull over and help a stranger may not be what they used to in some places, of course. For sure, jumper cables don't do you much good in situations where no one is likely to come by for some time (a suitably stored -- and reasonably charged! -- jump box might be your only friend there!) And people can be goosey about doing it wrong and frying some electronics. But a great many people, at least where I live, haven't gotten word that their days pretty much over...
Cheers, --Joe
Comboverfish - 15 Aug 2007 21:30 GMT On Aug 15, 2:31 pm, Ad absurdum per aspera <jtc...@california.com> wrote:
> Several years ago there was a brand of car battery that had a small > auxiliary built in. After a few minutes of coulda-shoulda-woulda [quoted text clipped - 3 lines] > seen those in a long time, though, and seem to recall them as having a > premium price, which might have been the reason. Didn't the first wave of these have the Champion brand name? I haven't seen them in years either.
> > The days of jumper-cables are pretty much over. Really small jump boxes are becoming popular now. I bought one back when they were a bit newer and no reviews existed for such a product. Luckily it has been absolutely great. I see no reason to carry around the larger portable type units (almost the size of a car battery), let alone a roll around monstrosity, when these mini jump units work so well. I wouldn't bring it to start a diesel though...
Toyota MDT in MO
Ad absurdum per aspera - 15 Aug 2007 22:24 GMT > Really small jump boxes are becoming popular now. I haven't taken one apart, but wouldn't be surprised to discover a row of lithium-ion laptop-computer batteries or at least the cells used therein. A lot of those batteries happen to have output of 14-ish V, and the economies of scale must be sizable.
--Joe
Comboverfish - 16 Aug 2007 12:37 GMT On Aug 15, 4:24 pm, Ad absurdum per aspera <jtc...@california.com> wrote:
> > Really small jump boxes are becoming popular now. > [quoted text clipped - 4 lines] > > --Joe I'll be taking mine apart when it fails -- hopefully not for 10 years though.
Toyota MDT in MO
Tegger - 14 Aug 2007 03:16 GMT Matt <matthewmpower@gmail.com> wrote in news:1187055612.315562.322410@ 19g2000hsx.googlegroups.com:
> How might it be possible for the jump-box to receive the alternator's > charge but not be drained by the forgotten dome-light? A diode?
 Signature Tegger
Matt - 14 Aug 2007 03:46 GMT "A diode?"
Thank you, Tegger.
Yes, I agree that a one-way gate is the trick here...
But how to make it happen in a real-life situation?
Where exactly might that diode be positioned? That where I am asking for some help.
Matt
qslim - 14 Aug 2007 13:08 GMT Diode?
On the positive connection to the 'on board jump box' (OBJB). Then have a separate circuit for 'jump starting' the main battery with a relay jumping the "DIODE" controlled from inside the car whose power supply would run off the OBJB, providing a direct connection between the car battery and the OBJB. How many ASEs do you have?
Kevin Bottorff - 14 Aug 2007 14:38 GMT > Diode? > [quoted text clipped - 3 lines] > supply would run off the OBJB, providing a direct connection between > the car battery and the OBJB. How many ASEs do you have? it is very simple, limos have been doing it for years. you use a solenoid to isolate the 2nd batt. and it charges and everything normally when key is on but is isolated when the key is off. also providing a built in boost when cranking. KB
 Signature Thunder Snake #9 "Protect" your rights or "lose" them.
Matt - 15 Aug 2007 02:02 GMT > > Diode? > [quoted text clipped - 12 lines] > Thunder Snake #9 > "Protect" your rights or "lose" them. Thanks, that makes perfect sense. I haven't seen one because I rarely service limos. Great response, thanks again for helping me to solve this little puzzle.
Matt - 15 Aug 2007 01:50 GMT > Diode? > [quoted text clipped - 3 lines] > the OBJB, providing a direct connection between the car battery and the > OBJB. How many ASEs do you have? It is besides the point, but I have 9.
qslim - 15 Aug 2007 03:24 GMT Scott Dorsey - 14 Aug 2007 15:25 GMT >What device might be created that would allow a jump-box to be wired >into a vehicle were it would be charged during vehicle operation, but >not drained when the vehicle was turned off? A diode block that goes between the alternator and the two batteries. You can buy such a thing at an RV store... lots of RVs and vans are set up with dual-battery systems so the RV appliances run off a deep cycle battery that is charged by the alternator, but which cannot discharge the starting battery for the vehicle. Same thing. --scott
 Signature "C'est un Nagra. C'est suisse, et tres, tres precis."
Mike Romain - 14 Aug 2007 16:20 GMT > I am a master auto technician, and I am seeking the opinion/advice of > other master technicians who work in the field. Wow!!!!
They have had dual battery setups for 4x4's and RV's for many many Many years with various types of isolators available.
Tow trucks are also set up with front 'plug in' booster cables and have also been this way for years!
How can someone 'claim' to be a 'master auto tech' and not know this?
Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590 (More Off Road album links at bottom of the view page)
cuhulin@webtv.net - 14 Aug 2007 20:06 GMT One battery, in your vehicle, and jumper cables.What more could you want? cuhulin
qslim - 15 Aug 2007 00:37 GMT Sorta the same thought I had...
Matt - 15 Aug 2007 01:57 GMT On Aug 14, 3:06 pm, cuhu...@webtv.net wrote:
> One battery, in your vehicle, and jumper cables.What more could you > want? > cuhulin Sometimes there is not another vehicle to jump off of. Another poster gave me a response that helped me think of the solution, so thanks.
cuhulin@webtv.net - 14 Aug 2007 20:10 GMT I used to drive a Deuce and a half truck (ammo truck) in Vietnam.It had two 12 volt batteries.I own a 1960's Mercedes Benz four cylinder diesel engine.It requires two 12 volt batteries. cuhulin
Matt - 15 Aug 2007 01:55 GMT > > I am a master auto technician, and I am seeking the opinion/advice of > > other master technicians who work in the field. [quoted text clipped - 15 lines] > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > (More Off Road album links at bottom of the view page) Thanks for the "Wow!", but I don't work on RVs or tow trucks. That's why I am asking for other technicians who might know. Thanks for the rhetoric, though. I am not interested in character attacks. Bye!
Mike Romain - 15 Aug 2007 14:55 GMT >>> I am a master auto technician, and I am seeking the opinion/advice of >>> other master technicians who work in the field. [quoted text clipped - 18 lines] > why I am asking for other technicians who might know. Thanks for the > rhetoric, though. I am not interested in character attacks. Bye! If you are a 'master auto tech', then it is no wonder the state of auto repair these days, sorry man but 'wow'...
Here you go then:
Back int he 60's when I started working in garages, we used a 'portable jump box' in the various garages I worked in.
It was simply a battery on a two wheeled 'suitcase' dolly with welding cable clamped onto the battery posts and ground clamps on the cable ends. This got charged up as needed.
It worked well.
Mike
tippybob@yahoo.com - 15 Aug 2007 02:44 GMT Matt,
http://bluesea.com/category/2/productline/236
This may be what you have in mind.
-Bob
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