Jump Start Your Car With Sega Parts


[Jenn’s] family is a single-car household. Because of this, it’s a little more difficult to get a jump start when the headlights run down the battery. Not wanting to ask the neighbors for help, her husband [Richard] decided to come up with his own solution.

Rummaging through the parts on hand, [Richard] went with his old friend Sonic the Hedgehog. He used two 12-volt, 1 amp Sega Genesis power adapters in parallel hooked up to a 12 volt, 3 amp  power supply. The end result is a 12-volt 5 amp source hooked to the car’s electrical system and used to get their road machine started.

We have enjoyed some of [Richard’s] offerings in the past, such as Super Nintoaster and the Super Genintari but this is a bit less… eloquent. A few questions do come to mind. First of all, is this the best way to use parts of your 20-year-old gaming system?  How many amps does your average car starter pull down?  And finally, what kind of issues are we looking at with the lead acid battery under these conditions?  Weigh in on the conversation in the comments.

47 thoughts on “Jump Start Your Car With Sega Parts

  1. That definitely would not be enough to jumpstart a car. IIRC starters draw hundreds of amps of current. The one in my car is fused for 200A. It depends on the temperature what it draws.

    Anywho he probably just charged the batteries up, and then started it.

  2. I would also guess that those power adapters weren’t actually limited at 1 amp each. I don’t believe that that type of transformer + rectifier commonly has any current limiting built into it and probably is only “rated” at 1 amp meaning it won’t start a fire at 1 amp.

  3. He used a generic power supply to charge a battery. wow.

    The only unique feature here is that the generic surplus wall warts in question were at one point used to power a video game as opposed to any other random electronics.

    That scraping sound you hear is the bottom of the barrel.

  4. horrible use of old console equipment IMO… if this was a one time thing it wouldn’t kill you to knock on your neighbor’s door for a jump. if this is a reoccurring thing then it’d be worth buying a legit battery charger.

    and definitely no where near enough amps to actually jump a car.

  5. Well you won’t jump start the car straight off them, but what you can do is leave them pushing 5A into the battery for a while to give it a boost.

    It might be enough to kick some charge into a marginal battery but that’s all – the starter motor on a big engine can easily draw 300A on a frosty morning.

    Top tip when jump starting any car though is to leave them connected with the “donor” engine running for 5 minutes or so. You can jump start a HumVee from a smart car that way!

  6. Now a real hack would be to wire in a on/off relay system hooked up to the power inverters. Then hook that up to your nip nips. Of course an arduino linked to twitter drives the on/off system. So whenever you receive a twitter update from your fart monitoring twitter arduino system, the nip nip arduino twitter system shocks you making you fart then updating the twitter account hooked up to your nips. Then after three hours of that, you stop enjoying that and die. The end.

  7. The power adapters may not be actively regulated, like many cheap power supplies, but they most certainly would have some sort of overcurrent protection, otherwise they would pose a safety hazard. It could be just a fuse.

    That said, in this case the supply would be at 12V ideally, while the load (battery) has significantly less voltage, being mostly discharged. If the supply really did output 12V regardless of load, it would surely blow its fuse with the discharged battery attached. As [Fallen] said, batteries can take much more current.

    I’m going to guess that this supply is current-limited, having an output voltage that is only slightly greater than the battery voltage so as to maintain a 1A current output. Only when the battery is ~12V will the supply actually output 12V and turn down its current.

  8. Well now that his car is started/fixed, he will have a gasoline powered 12 volt source for his video game consoles which he ruined the ac adapters for. Can’t wait for the hackaday article on how many game consoles work off 1 cigarette lighter.

  9. Those little jump boxes, with the internal rechargeable battery, are fantastic. I’ve used mine dozens of times, mostly to jump start other people’s cars without messing around with cables and awkward parking. Anyone with a fossil fuel powered car should have one sitting in the trunk at all times. As a bonus for gadgety types, it’s also a solid portable source of 12V, some even have built-in 120V inverters.

  10. As others have suggested – not all warts are current-limited.

    I found out the hard way, powering a device that drew more current than anticipated, with a wall wart that happened to be laying around in my parts bin. No fire, no damage, but about 10 minutes into the test, I smelled something funny, and it wasn’t coming from the device under test. Took me a while to realize it was coming from the area of the power bar, and that the AC adaptor got enough that the plastic casing had begun to deform.

    Oops. Shut things down, waited for correctly-specced wall wart to arrive.

    Upon disassembly, there was no fuse, just a small transformer and a couple of diodes. I suppose that in the event of a dead short, the transformer windings would have failed, and/or some solder would have melted, but I didn’t particularly want to find out the end-state of this particular unit’s overcurrent failure mode.

  11. @ macegr the little jump boxes are a 7ah battery in a box. very overpriced little box

    i think this is another in a long line of “not-a-hacks” that’s been here lately. he hooked a ps up to a battery and charged it.

  12. @ Zero, Justin, and learnedthehardway:

    Obviously not all, due to learnedthehardway’s experience, but most linear (non-switching) wall-warts are deliberately designed to have a sloppy, poorly coupled transformer, so that even if the output is shorted, the transformer will not heat up enough to be a fire hazard. It will get uncomfortably hot, but not a fire hazard.
    This is part of the reason why these wall-warts are falling out of favor, replaced by switchers. Linear wall-warts are deliberately inefficient so that they can not provide dangerous amounts of power on their output.

  13. I’ve done this years ago with an old AT power supply. I didn’t realize it at the time, but a charger has to be at least 13.8 volts to actually charge a battery to 12 volts. IIRC, after a full day of charging, the battery only put out about 10.6 volts, which was *just* enough to get the car started.

  14. That’s not as cool as jumpstarting a car with a wirefeed DC MIG welder. I did that once in a pinch. DC welders put out like 100 amps, so I measured the voltage at the electrode wire during a “weld” cycle and dialed it down to around 12v. Then wired the electrode wire to the pos. and the ground clamp to the neg. and taped the trigger switch down while I started her up. I don’t recommend it, but it worked for me.

  15. :P If it counts for anything, I had modded some ATX power supplies to output 2.7-20V on their 12V rail. I had 4 of them paralleled, through mosfets(positive temperture coefficient ensured that all supplies shared the load equally.) Each of the 4 PSUs was rated for 25A on the 12V line. I figured a good test would be to disconnect the car battery and see if it could start the car. And it did. But I was more of less using the car as a 100A load. I wish I took pics of this thing, I was using it to power a damaged car audio amp when I was trying to repair it(it would shut down if there was not enough current available on startup, and it took a lot of current to charge it’s bank of caps on the secondary side of the SMPS).

  16. While not particularly exciting, in spite of some peoples’ doubts it’d certanly work. Lead acid batteries will act like capacitors if briefly charged – a minute or two of charging will let them kick out 100A at 12V

  17. how is this NOT a hack? it’s a quick and dirty, cleverly improvised solution.

    sorry, but a long and thought out complex electronics project complete with thorough documentation, professionally printed PCBs, etc. is not a hack, it’s a project.

    this is a hack.

  18. “Top tip when jump starting any car though is to leave them connected with the “donor” engine running for 5 minutes or so. You can jump start a HumVee from a smart car that way!”

    You can jumpstart a SEMI that way.

    /Been there, done that. Though, it’s more like 10 or 15 minutes.

  19. Lots of wall wart adapters have no fuse. Instead they have a transformer rated at specd current. Exceed that and the winding shorts breaking the circuit. The wire attached to the lead in of the transformer becomes the fuse.
    UL even approves them this way as safe.

  20. Cheap, unregulated AC adapters usually have no overcurrent protection. For safety there is often a thermal fuse inside the transformer in series with the primary winding.

    @tyco Small line transformers are inefficient (compared to larger types) by their very nature, they are certainly not made this way for safety reasons.

  21. Agreed @ most above. This thing MIGHT work once in the summer, with a potato hooked to the antenna for good luck. Otherwise, put a sheet of foil under the PSUs so it is much easier to clean up the melted plastic. Now THERE is your hack. My battery is rated for 400 “cold cranking” amps. 1-3 or even 10 amps would be so incredibly iffy. I guess you could use it to power the radio while you wait for AAA or a neighbor to wake up. Just pony up the $20 for a plug in starter or beat your wife and kids without mercy everytime one of them “forgets” to turn off the electrics of the car. Most people/things memories are about half as long as what you hit them with is a good general rule.
    Anyhoo it was interesting to say the least and the type of hack that would have my wife watching me, shaking her head, with 911 dialed and waiting to hit send lol.

  22. @NegativeCommentors

    You actually took the time to dis this post instead of creating your own hack to impress us? If you don’t like it, scroll down to the next one! I thought this was pretty funny and should be on ThereIFixedIt.

  23. mjrppe I don’t think people are so much dissing this as saying it is scientifically unfeasable and possibly dangerous to everything involved. Then again that doesn’t stop most of us. I would have been more impressed with a proof than what was given.
    Comment section-yeah that is where people put comments good or bad. Why not create your own hack instead of bashing everyone as you suggest. The best leadership is by example.

    A final piece of advice my dad gave me when I was eyeing my first car battery. “Son, it ain’t the volts, it’s the amps that kill you.”

  24. You fellas crack me up.
    The bottom line is, it took me all of 15 minutes to gather up some spare crap I had laying around, jump the car and get to the grocery store. We bought a chicken. Threw that bastard in the slow cooker with some potatoes and carrots, it was delicious.
    Would I recommend starting a car this way? Hell no. Are wall-wart adapters designed for this? Absolutely not. Did it ultimately get my ass to the grocery store? Sure did!
    Swear to God I didn’t think it would actually work, but it did, and I laughed about it for the rest of the day. I don’t really have anything more to say about it.
    Moving right along…

    1. You could have poked a nail 3/4″ into ea end of a hotdog, wired it to 120, and saved yourself a trip and a.lot of angst, mainly from some detractors here. LMAO with you. But try this. Half of the time, 1 end of the hotdog glows like a neon light when it’s ready, 30-60 seconds. And you can prep the dogs with condiments, in a bun, plug it in, and only the dog gets hot!

      Next up, How to disoense an avocado without cutting it open. Cut the end off and squeeze. Ok – it must be soft, or roll it on a counter as if totally cracking the shell on a hard-boiled egg for perfect eggs. That’s how YOU do it… right?!?

  25. excellent! it made it! :)

    i’m no techno-wiz, so i don’t know what’s /supposed/ to work. but this did! when he got that glint in his eye after learning that the battery was dead, i knew i had to get the camera… and stand way way back. my one regret is that i didn’t use video for you skeptics. absolute failure was on my mind as well; either something would spark and explode, or he would be stubbornly trying until someone could be reached.

    i too don’t understand what some of you are saying. we don’t have a jump pack, or second car, or any other power source to start a car. but he did have adapters and it turned the engine over. probably won’t be doing that again, but now we know it works! :)

    in case some of you are confused, he did not charge the battery with the wall-warts; merely turned the car over and disconnected everything.

    carry on hackers!

  26. okay people. you do realize every run of the mill car battery plug in AC to DC Charger works exactly like this. not impressive. and why is the article titled with sega parts? all he used was the ac adaptors (could have been any ac adaptor). I like Biff’s Welder hack much better. its dangerous yet intuitive.

  27. Aside from what others have said, I’ll add some trivia.

    In the winter if the starter is pulling 300A, and you have an average of 5 feet of cable running from the battery to the starter, the voltage at the terminals of the starter will be around 10 volts.

    Now, lets think about jumper cables. Assuming 8 gauge wire 15 feet long (some are longer than this and I’m being generous on the gauge used), the voltage drop between the vehicles can be as much as 6 volts and that doesn’t count the wire leading to the starter.

    Sometimes it’s amazing it even works when it’s done correctly…

  28. Hybrid, by any chance? They use the traction battery to turn the motor generator for starting purposes. If the 12v “house battery” dies, though, it can prevent the car from starting (since the computer won’t startup). Supply 12v power, even a couple amps, and all is good. I’ve read about people doing it with a 9v battery.

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