It's electric.
October 21, 2015 1:16 PM   Subscribe

I wish to adapt. I have this zappy shocky thing, which works with either 9V batteries or a wall adapter. Unfortunately, even with good 9V batteries it does not last very long, and the wall adapter does not charge any rechargable batteries in the unit. I would like to use something like external phone batteries to keep it active for longer periods of time when not near a wall outlet.

The included AC adapter outputs 9 volts at 3.5 watts, but the power port in the unit is a 3.5mm jack format, which I can't seem to find any cables for online. Where the 9V battery is placed inside the unit it is a flat metal flange instead of the 'bumps' that 9V batteries sometimes attach to, so an adapter that snapped directly to that would not work.

What I am looking for is either a specific cable that will go from USB like on the above power packs to this type of plug, or the specific name of the headphone jack type that might come up with Radio Shack or something, or something shaped like the 9V battery that would go in the battery slot but is instead just an adapter to the external cable.

Thank you for your help!
posted by Evilspork to Technology (19 answers total) 1 user marked this as a favorite
 
How about cutting off the connector from the power supply, soldering on matching connectors on both sides of the cut to put it back together, and soldering another matching connector to the external battery?
posted by fmnr at 1:30 PM on October 21, 2015


I'm pretty sure those external phone batteries are 4-6V range.
posted by three blind mice at 1:36 PM on October 21, 2015 [1 favorite]


Unfortunately, I don't think answering your question will actually help you. As noted above, you have a voltage difference problem. A standard phone powerbank will probably not supply the voltage level you need to run your zappy thing.

I think you have one easy option, and one that is more like what your picturing but harder (and more expensive).

The easy option is just get rechargeable 9v batteries.

The second option is to go to a rechargeable battery meant for other purposes (for example), and cobble together a charger and correct cables.
posted by achrise at 1:47 PM on October 21, 2015 [1 favorite]


Response by poster: Sorry, that battery link was just a quick example and poorly chosen. There are 9V capable packs out there, though that one for example is 1.8A vs. ~0.4 for the AC adapter. The zappy thing has amplitude adjustment; as long as the voltage was correct, am I correct in thinking that the ~4x amprage difference would be OK as long as I turn the dials down to ~25%?

I was thinking those phone batteries due to ease of use and rechargability, though I am open to other options. I don't know how to solder or have soldering equipment, though I've stripped wires and used those wire twist crimper things before. I would also like whatever I do to be at least somewhat reversible/nondestructive, so cutting the wires on the AC adapter would be undesirable. :)
posted by Evilspork at 1:58 PM on October 21, 2015


That unit you linked to can get charged FROM an assortment of voltages; it apparently puts out only up to 5 volts.

Can you get a replacement power supply so that you can cut the wire off of that? That, and a battery pack that will hold 6 AA rechargable batteries might do the trick.
posted by BillMcMurdo at 2:19 PM on October 21, 2015 [1 favorite]


Response by poster: Yeah, the first one I linked seems to be just 5V, the other one shows:

Specifications:
Input: 5V/2.1A.
Output: 5V/2.1A, 9V/1.8A, 12V/1.35A

I didn't think about stacking AAs, I will look into that.
posted by Evilspork at 2:30 PM on October 21, 2015


By "3.5mm jack" do you mean it's like a headphone jack (no center pin), or a 3.5mm barrel jack like this? The latter is reasonably common, although 5.5mm is the "standard" size.

6 x AA batteries would last a lot longer than a single 9V, if you can figure out a way to connect it. (Fun fact: most 9V batteries are actually a bundle of six AAAA batteries in series!)
posted by neckro23 at 2:34 PM on October 21, 2015 [1 favorite]


Response by poster: Correct, it is literally the same format as a 3.5mm headphone jack, not a normal barrel plug, which is why this is such a weird problem. The only difference from a headphone jack is that it only has one separator ring, not 2-3.
posted by Evilspork at 2:40 PM on October 21, 2015


Response by poster: Here's a picture. The adapter is the one on the top, with the single slightly wider separator ring towards the tip, and a normal headphone jack is on the bottom.
posted by Evilspork at 2:49 PM on October 21, 2015


Best answer: Quick note: The cheaper battery packs (like the second one you listed) that claim 5V/9V/12V output are all using the newish Qualcomm Quick Charge standard, and AFAIK they'll just output standard 5V USB power unless they're attached to something that can communicate back to the charger that it should enable a higher voltage charging mode... which, at this point, is mostly just a few Android phones.

There are USB battery packs that will do switchable 9V/12V over a barrel connector, but I think most of them cost more than your zappy shocky thing.

You'll probably be best off buying a bare battery sled that connects 6 AAs in a series from somewhere like Digikey, and soldering on an appropriate TRS plug (although you'll have to figure out the polarity of the original charger).
posted by drumcorpse at 2:57 PM on October 21, 2015 [1 favorite]


Best answer: Your image is unavailable, but it sounds like you want a 3.5 mm mono audio plug like this. Mono is the key.

How long does a 9V alkaline battery last you? How long would you like it to last?
posted by JackFlash at 3:20 PM on October 21, 2015 [1 favorite]


Best answer: on your question about volts and amps:
  • you need to provide about the right voltage (too low and it probably won't do anything, too high and it will break)
  • you need to supply at least the amps of your current battery (too low and it probably won't work properly, but too high is not a problem - it simply won't be used).
so you don't need to turn anything down if the amps rating is higher. it will just be "ignored" (the only downside to higher amps is it means the battery is likely more expensive).
posted by andrewcooke at 3:33 PM on October 21, 2015 [1 favorite]


Response by poster: Oops, here is the correct link to the picture, I had uploaded a blurry one, copied the link, deleted it, then forgot to copy the second upload link. Yes, the tails you linked are the same.
posted by Evilspork at 3:41 PM on October 21, 2015


Best answer: For a cheap big 9V supply, you could just duct tape end to end 6 AA, 6 C, or 6 D cells together like a big flashlight. That is essentially what is inside your 9V battery -- six tiny 1.5V batteries connected end to end.

A stick of 6 AA batteries would give you more than 4 times the run time of a 9V battery. A stick of 6 D batteries would give you more than 20 times the run time of a 9V battery. This might be cheaper and physically easier than trying to connect a bunch of 9V batteries in parallel.

Use the 3.5 mm mono plug from above for your connection. Be careful you get the polarity right.
posted by JackFlash at 3:42 PM on October 21, 2015 [1 favorite]


Best answer: Two possibilities:

The cheap, lower capacity solution is using AAs as JackFlash suggests. I would use a battery pack like this, rechargeable NiMH batteries (like Sanyo Eneloops), and connect this to a mono audio cable end as linked above.

The more expensive, higher capacity solution would be to use a 7.4V Li-ion battery. A 7.4V Li-ion battery, despite the much lower nominal voltage, is very close in actual voltage to a 9V batter. You can get basically any capacity you want. You will need to buy one with a charger and then make a wire to connect from the battery connectors to the mono plug that can be removed to allow charging.
posted by ssg at 8:36 AM on October 22, 2015 [1 favorite]


Response by poster: I am willing to put a bit of money into this, so maybe the 7.4V battery type you mention would work. I am shooting for something compact and easily attachable to clothing, which is why the phone packs were appealing.
posted by Evilspork at 12:43 PM on October 22, 2015


Response by poster: Looking for the 7.4V batteries, I saw this product. It specifically does not use Qualcom iSmart and has selectable voltage. Yay me!
posted by Evilspork at 1:32 PM on October 22, 2015


Best answer: Just a comment on why they are using an audio jack and socket instead of the more standard barrel connector for power.

You don't want to have your 9V battery and the external supply connected at the same time because they won't generally be exactly the same voltage and high, damaging currents could flow between them. Many audio sockets have a switch built into them that opens when you push in the plug. This switch automatically disconnects your external speakers when you plug in your headphones. Well, they are using this same audio switch mechanism to disconnect the battery when you plug in the external power supply. It's kind of a goofy trick, but it's cheap and saves them a few cents by eliminating the need for an electronic switch.

So the audio plug you put on your external supply should work similarly. When you plug in your external supply it will automatically disconnect the internal 9V battery. You can test this before you assemble your external supply by turning on the unit with the internal battery. Then push in the unconnected external plug. The unit should stop working if the internal battery is switched off as expected by inserting the plug.
posted by JackFlash at 11:01 PM on October 22, 2015 [2 favorites]


Response by poster: Yes, some of the reviews mentioned exactly that function (that the external power wouldn't damage the battery by disconnecting it) but not that it was the plug format itself that did it. Neat!
posted by Evilspork at 12:12 PM on October 23, 2015


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