What's The Deal With Cigarette Lighter Jump Starter Devices?

June 26, 2015 3:28 PM

I've had a couple dead battery incidents (left the lights on, etc), so I decided to start looking for some jumper cables or something for the inevitable "next time" this sort of thing happens... and I was wondering -- are the smallish portable devices that connect via the cigarette lighter a good option?

Basically, I'm wondering why the scary-sometimes-sparky clips are still used if the cigarette lighter is actually just as good for jump starting a car? I assume it's not, but if it is... it sounds/looks so much more convenient than popping the hood and figuring out where to clip what to what. (A tow truck guy even had some problems trying to figure out where to put the ground clip on my car b/c newer cars' engine bays are made of a surprising amount of plastic these days....)

So anyone have experience using a cigarette lighter jump starter? When does it work and when doesn't it work? There are all kinds now -- that have lithium ion batteries that can recharge phones as well -- so.. is there are recommended mAh capacity for these things? (Does anyone sell a USB to cigarette lighter cable? Is it possible to use a battery charger that I already use for my phone?)

posted by mhh5 to Technology (11 answers total)

I would expect that the rate at which a cigarette lighter charger can charge a battery is limited by the fuse on the lighter circuit, so as long as you're willing to wait an hour or two, they're probably OK. I could be incorrect, though, as I have not used one personally.
posted by jferg at 3:36 PM on June 26, 2015

Best answer: Here is an explanation. The short version is basically what jferg said: Not really, there's a fuse in the way.
posted by aubilenon at 3:42 PM on June 26, 2015 [1 favorite]

Best answer: The problem is that the cigarette lighter provides far less current than the direct battery-to-battery connection (which is actually also an alternator-to-battery connection, maybe more to the point) so even if it works in theory, it would take a whole lot longer. Reading a couple Amazon reviews, this does indeed seem to be the case - they even advertise that it takes 10 minutes to get a start, and the reviews indicate you might have to sit through 2 or 3 10-minute cycles to really get it done.

Which... is fine, if you have two cars sitting near each other in the garage and you can hang out for a while. But a very useful aspect of the full size jumper cables is that you can get a jump anywhere from anyone in under like 2 minutes because it's effectively using their whole electrical system to charge and start your car during that time. The cigarette lighter ones can use only a tiny fraction of that remote power.

Is it possible to use a battery charger that I already use for my phone?

No. That won't provide anywhere near the current even of those low-current models. You would definitely need a heavy-duty cable connecting the two cigarette lighters.
posted by Joey Buttafoucault at 3:46 PM on June 26, 2015

Oh also:

Is it possible to use a battery charger that I already use for my phone?

Nope, not without a transformer. Car batteries are 12V, USB chargers use 5V. But also car batteries also have about 100x the energy capacity of a phone. So it's not a viable approach.
posted by aubilenon at 3:48 PM on June 26, 2015

Response by poster: Thanks, hivemind. I figured there must be something that makes those lighter chargers less than ideal -- just couldn't put my finger on what it might be. A fuse makes sense -- that and there not being a direct connection to a battery and no wires with insulation that look sturdy enough to handle a pretty good jolt.
posted by mhh5 at 4:23 PM on June 26, 2015

As far as the "where to clip what to what" problem, most car manuals I've seen will have a section on jump starting procedures that indicate the manufacturer's recommended placement. They'll give the proper order to connect/disconnect the cables and indicate where they should be placed.
posted by zachlipton at 4:44 PM on June 26, 2015

I did see a review for something on Engadget that was a car with jumper cables and all, but was really small (like ipod size) and had USB connections to charge electronics as well. Maybe I misread it and it was one of these lighter chargers as well.

Nowhere near as convenient but in my car I have a big multifuction unit with a battery for jump starting the car, air compressor for inflating the tires and light for seeing what you're doing. I've only had the chance to use it to jump start my car, but it did the job so I'm happy with it. It also has USB ports for charging electronics, which was useful when we lost power for a few days during an ice storm.
posted by any portmanteau in a storm at 6:09 PM on June 26, 2015

I did see a review for something on Engadget that was a car with jumper cables and all, but was really small (like ipod size) and had USB connections to charge electronics as well.

I have one of those (there are several brands). I haven't had a chance to use it since I bought it a year ago (drat?), so I can't personally speak to their utility. However, the one I purchased seemed well-reviewed, as do other versions.

In any case, they don't take up much space at all -- seriously, they're about the size of a smartphone or a traveling external hard drive -- and could probably work for your needs. I heard about via boingboing, which is kind of obsessed with portable jumpers/chargers: lots of reviews and writeups over there.
posted by credible hulk at 7:03 PM on June 26, 2015 [2 favorites]

There's also a class of portable devices larger than the ones you're talking about -- about the size of a car battery with jumper cables attached. They're less portable than the really small devices but they work nicely for starting a car with a dead battery, so if you usually find your battery dead while sitting in your driveway or near your house they're a good option.
posted by Nerd of the North at 8:29 PM on June 26, 2015

TL;DR version -- those cables generally takes... 30 minutes or more whereas if you open the hood you can do it in about 30 seconds. That's because in most cars, the circuit on that is limited to 10 amps (i.e. 10 amp fuse) and most devices stay safe and don't try more than 5 amps. So it will take FOREVER.

Thus, it is better to look into a jumpstarter that's more portable, but clamps directly to battery.

There are supposedly latest batteries that can do fast discharge and has the same capacity albeit in a much smaller package than the typical jumpstarter, but you're looking at glove-box fit rather than trunk fit.

http://www.cnet.com/news/pocket-sized-jump-starters/

And even better, they can charge your phone too. :)
posted by kschang at 11:44 PM on June 26, 2015

The cigarette lighter one is the type you keep in addition to standard jumper cables and not in lieu of them. I think the cigarette lighter ones would be handy to have in case one is stranded somewhere without another car to help.
posted by terrapin at 7:56 AM on June 27, 2015