We often start in a remote location, or in some small town. I always worry about that and yesterday it came true. After the ride, my brother's POS Geo Metro wouldn't start. We were in a tiny, tiny town. But, I had one of these batteries to jump start his car and off he went. I could have used my car, sure, but if you are ever alone with no one to help out, this could be a life saver. I've carried in my car for years and this is the first time I've used it. Recommended by my mechanic after he got stranded on a camping trip and had to hitchhike into town.

I don't have a link handy, but the coolest jump starter I ever saw literally jumps starts a car using its own battery. Generally, a dead battery will still have enough power to turn on some lights or click the starter solenoid. This gizmo connects to that power, charges itself up for awhile, and then provides enough amperage to start the car. While it obviously needs some power from somebody's car to work, the advantage is that you don't need to carry around another charged-up device.

How can this possibly work? You're moving the energy from the depleted battery to another, but there's no energy in the gizmo than there was in the battery.

My spouse owns a car and I don't. It's a Tesla. Sorry, we didn't know how big a maniac he was when she purchased. With that out of the way, I gotta say that in most ways, an electric car is more convenient than a gas car. Jump starting a Tesla is not possible, though. We have to watch the level. The car and software helps a lot. We often use the navigation system even when we know the way. The system predicts what the battery level will be at our destination, with stunning precision. I can see it even takes the hills into account, predicting that our level will be higher at the bottom of a hill after descending. The system also knows if we won't make it without charging on the way, and it recommends one or two locations for charging that are on our route. Refueling does take more time than with gas. It's rarely a problem. At our weekend house, we have a charging cord on the outer wall of the barn so refueling there takes only the time to plug in. It charges while we sleep.

I guess my point about jump starting is that we'll be out of luck if the car is ever discharged and not near a charging point, but because of how they built the car and network, it is unlikely to happen, even in the winter. It's a benefit of an electric car that many may not know about.

I don't know if I would enjoy having an EV if my travels didn't take us out of Manhattan. Parking and charging are expensive here. We've never charged in Manhattan.

Pretty counter intuitive, right? Look up the word "capacitor". It charges itself slowly from the almost dead battery and then is able to release all that energy in a sudden burst that can start the car.

Another question involving the Second Law of Thermodynamics:

How much does this cost, relative to a AAA membership?

It's not the cost. Its's getting back on the road vs. waiting an hour or more for a rescue. AAA is great, but self rescue is also great.

Sorry. Not everyone has the capacitance for my highly charged sense of humor. ;-)

(I couldn't resist).

I used to drive MINI Coopers. (Had a '65 Mk 1 too, back in the late '60's but that was a different beast....) Last one was a Gen II 2013 Clubman, complete with CANBUS electronics. Survived a sunroof drain leak that ruined one of the 'controllers' adjacent to the fusebox in the passenger compartment's footwell, as well as saturating the fitted carpeting in the front. That all ended well enough when my insurance paid the R&R bill, got me back on the road.

In July of '23 said Clubman 'died' in a parking lot 9 miles from home. Even bump-starting wouldn't get it going, yet the battery was fine! Turned out there was a small, brained copper ground wire betwixt the starter and its solenoid that had corroded in the ten years since I'd bought it. Fully exposed underneath to all kinds of environmental contaminants like the salt used on Midwestern roads in winter, it finally succumbed hence stopped grounding the solenoid. Seems this factor had some effect on the CANBUS electronics that also disabled the ignition system so even bump-starting this 6-speed manual equipped vehicle was rendered impossible.

Local repair shop fixed the problem in a day with a new starter for $120, which the tech told me was a b*tch to install owing to the engineering of such a compact FWD vehicle as these newer MINIS.

Last Friday I got a 'call of shame' from my wife, who's owned and still drives a 2006 MINI Cooper S Cabriolet since October of that year. A mile away it failed to start yet the battery was fully charged I later found out when I went to her rescue. With jumpers later I found it wouldn't start, yet everything else electrical would function just fine.

So it's sitting in a shop's yard presently, awaiting their techs' investigations into WWW last week. I have my suspicions, but as her MINI doesn't use the same motor as did my 2013 Clubman (traded in 2022 for a stick Subaru Impreza) I'm hesitant to go with the same component failure prognostication.

Could BMW really be that reluctant to fix a 'known' issue over such a long production cycle?

I had a BMW about 15 years ago and it went into "limp home mode" a couple of times. Several shops looked but the only one that had a solution cost $4500. For a ten year old car with 150,000 miles

Not familiar with your car, but two things I am pondering:
1. Did you ever successfully try bump starting it before the wire in the starter failed?
2. Isn't the starter solenoid, wire or not, still grounded via its mounting to the actual starter?

while I won’t say it’s not possible, a capacitor has to receive energy before it stores it, not sure how it would receive energy or energy from a dead battery.

If it there was an ability tto suck amperage from a dead battery, wouldn’t the energy removed equal the amperage it could push back out at best, which of course wasn’t enough to start it in the first place?

I’ve had a couple jump packs over the years, and been in the Tool business for over 25 years, this is one the best I’ve seen and or used. Have the 650Amp (I believe off the top of my head)

I guess an active device could charge itself up from a dead battery. The dead battery might never charge again though. It also might be dead enough to cause electrical problems on the drive home. I would be interested in knowing if that's how it works.

I just realized that finding such a device with google is nearly impossible, because google's algorithm thinks it knows better than you what you're looking for.

Oh, it's a capacitor! OK that makes sense. Thanks.

But you only get one shot!

Not sure if a AAA membership would have done me much good after parking here for nine days last fall. Cell coverage there is hit and miss.
https://maps.app.goo.gl/SS7GR8E55J3vzvSf6

That is why I have the extra large battery in my vehicle and the battery is only two years old. I also have an extra battery for jump start.

I usually see a couple other vehicles in the trailheads I start at, not this time.



The first night out, the Northern Lights were pretty good.

Yes, just once, as a lark when parked on a garage ramp. More out of curiosity than necessity though, and the engine was warm.
The day it died from the broken ground thingy it was ~ 92°F here and I'd been shopping for maybe twenty minutes so the engine had to be warm then too.

Practically minded folks would assume that's a yes I suppose. I know it came as a surprise to me when the mechanic showed me the failed component after the fix had been installed.

My take is that these CANBUS electronic creations have all kinds of sensors involved in the make/break decisions they control before anything happens. That broken ground connection may very well have 'faulted' a step in the ignition 'ON' sequence making any attempt at getting things to run as before well nigh impossible.

This incident was after the repairs effected post sunroof leak-related damages to the electronics so that might have had something to do with it also. Yet, once the starter / solenoid component was replaced, all was good once more.

As for component grounding, I've been informed by that same mechanic that the Subaru I'm now driving should have the ground straps between its engine heads and block assemblies checked periodically. Seems they can be prone to loosening or outright failure as well.

Sometime I'll relate my experience with the 2007 MINI Cooper S I owned and drove before trading for the Clubman late in 2012. At least with that I had the foresight to buy a third-party warranty coverage which paid for itself 2-1/2 times while I drove it....

Those little jump starters sure are handy. Recently bought one. Don't know if I jinxed us, but the alternator on our '05 Civic tanked just a few weeks after.

I do have AAA, but there are lots of areas with poor cell coverage. Those seem to be the best areas for cycling too.

Related story: many years ago I had to give a jump to someone in a parking lot. New BMW, probably 25 years ago and I couldn't find the battery! Turns out, it was in the trunk.

My Volvo has the battery in back under the luggage area, you need to remove a few bolts to remove the cover over it. Or, under the hood, there is an electrical terminal in a convenient spot for jump starts, but you may need the owners manual to find it.

Having had the pleasure of a flat battery after three days camping, the battery was dead enough that my jump starter, an ITechWorld, wouldn't kick it over. I have since learnt (thanks, YouTube) that disconnecting the battery and then connecting the jump starter battery directly to the cables gets around the battery issue. All that said, having watched Project Farm, I now have a GooLOO GP4000 on the way.


Oh, we got going again by walking a couple of kilometres to the main road where there were roadworks underway. A couple of blokes gave us a jump start. Mind you, they even had some trouble getting past the battery. We could have called RACWA, but they would have taken at least two hours to arrive and maybe not been able to find us as we were down a few dirt tracks in the bush.

The Autowit Super Capactitor Jump Starter is one such beast. Project Farm (see video above) has tested it.

Yep, common enough to trip some folks up still.

My first car was a used '65 Austin-Cooper 1275 S. "Compact" enough it had no 'real' trunk, so they'd stuffed two 6V batteries (series-cabled under the rear passengers' seat.

Had two gas tanks too, one over each rear wheel.

The first 'new' MINI I bought in 2003 – brought to these US shores once more through the efforts of BMW to resurrect the marque – had its 12V battery in the trunk. Wife's '06 is of that same vintage, that's where the battery's hidden.

Some small portable starters can use a power supply that is greater than 12 volts.

Years ago I needed a jump start on my 1989 Jeep Comanche, the mechanic used a high voltage starter. The lighted controls on my radio never worked after that, some of the running lights were also burned out. Fortunately my dash lights were set for dimmed, those bulbs did not burn out.

If you try that, be careful that the engine is never running with no battery connected. Any voltage spikes could play havoc with your electronics.

Keep your starter battery connected while you attach the cables to the vehicle battery.