How do I replace this battery holder?
July 29, 2021 11:50 AM Subscribe
The battery holder for one of my bike lights died yesterday and I'm having a tough time finding a replacement. Any suggestions/links to products would be appreciated as well as suggestions on what exactly to search for.
Here are some photos of the broken battery holder. It takes 3 AA batteries. I've got a flashlight that has a similar holder but that has the positive terminal on one side and negative on the other. This one has the positive and negative on the same side.
This is the actual power pack that my battery holder is a part of. Sadly the company doesn't seem to be running right now otherwise I'd just get it from them.
I'm guessing that if I can't find a like-for-like replacement I can just get one of the flashlight ones and modify it but I'd rather not do that.
Here are some photos of the broken battery holder. It takes 3 AA batteries. I've got a flashlight that has a similar holder but that has the positive terminal on one side and negative on the other. This one has the positive and negative on the same side.
This is the actual power pack that my battery holder is a part of. Sadly the company doesn't seem to be running right now otherwise I'd just get it from them.
I'm guessing that if I can't find a like-for-like replacement I can just get one of the flashlight ones and modify it but I'd rather not do that.
Response by poster: Somehow some of it has expanded, warped, and stuck to the bottom. I'm not entirely sure what happened as the batteries still look and work fine and the light itself went to "battery is going to be empty soon mode" which is why I thought to open up the battery pack at all. I had to damage the holder in order to remove it from the rest of the battery pack and I don't think I'd be able to fix it. Modifying a flashlight battery holder would probably be the easier fix.
posted by any portmanteau in a storm at 12:11 PM on July 29, 2021
posted by any portmanteau in a storm at 12:11 PM on July 29, 2021
I'm pretty sure I could fix that with some glue and a bit of judicious 3D printing.
But given that it's just a separate battery pack, I'd just pick up one of those flat battery boxes (plenty for sale on Amazon, eBay etc.) and solder on the lead from the old pack. You're unlikely to find one to match the original - usually they're made for AAAs, not AAs.
posted by pipeski at 12:41 PM on July 29, 2021
But given that it's just a separate battery pack, I'd just pick up one of those flat battery boxes (plenty for sale on Amazon, eBay etc.) and solder on the lead from the old pack. You're unlikely to find one to match the original - usually they're made for AAAs, not AAs.
posted by pipeski at 12:41 PM on July 29, 2021
Yes, the easiest thing is probably to find a similar battery pack and splice the connector to it. I'm assuming there are no electronics there, and it's just a plain 3.6 V series connection.
One thing you might also consider is to switch to a single 3.7V 18650 or 21700 Li-ion battery. It'll be rechargeable, and it'll give you up to 3-4x the battery life of even the best AAAs. I can't seem to find any suitable single-cell waterproof battery containers for sale, but they surely must exist.
If you do try to reuse the waterproof shell, an 18650/21700 may well fit inside, in which case it might actually be easier to hook that up than to try to fix/create a 3x AAA holder. You'd also need a charger, but it shouldn't be too hard.
posted by alexei at 3:57 PM on July 29, 2021 [1 favorite]
One thing you might also consider is to switch to a single 3.7V 18650 or 21700 Li-ion battery. It'll be rechargeable, and it'll give you up to 3-4x the battery life of even the best AAAs. I can't seem to find any suitable single-cell waterproof battery containers for sale, but they surely must exist.
If you do try to reuse the waterproof shell, an 18650/21700 may well fit inside, in which case it might actually be easier to hook that up than to try to fix/create a 3x AAA holder. You'd also need a charger, but it shouldn't be too hard.
posted by alexei at 3:57 PM on July 29, 2021 [1 favorite]
Have you tried just putting a D-battery in there?
I remember seeing 3xAA to D adapters and they look almost identical to that.
Here's one example off eBay
posted by kschang at 4:42 PM on July 29, 2021
I remember seeing 3xAA to D adapters and they look almost identical to that.
Here's one example off eBay
posted by kschang at 4:42 PM on July 29, 2021
kschang: the problem is that (most likely) the 3-pack in question is wired in series, so it puts out 3.6-4.5 V, while those adapters are wired in parallel, putting out 1.2-1.5 V. Hence my suggestion of trying a Li-ion battery.
Actually, this made me realize that while I assumed it was in series, it's not clear from any of the information provided. But you can check it by inspecting the broken holder-- if it connects each positive end to a negative end, it's series. If all positive ends are connected together, it's parallel. But I'm pretty sure it's series (otherwise, why not use a D cell from the start?).
posted by alexei at 7:37 AM on July 30, 2021
Actually, this made me realize that while I assumed it was in series, it's not clear from any of the information provided. But you can check it by inspecting the broken holder-- if it connects each positive end to a negative end, it's series. If all positive ends are connected together, it's parallel. But I'm pretty sure it's series (otherwise, why not use a D cell from the start?).
posted by alexei at 7:37 AM on July 30, 2021
This, for example, would work (with the caveat that you'd need an additional connector for your lights, and that a lot of these generic batteries don't hold nearly the charge they claim, and these don't claim all that much-- you'd probably have better results putting together your own with batteries from a reliable source).
posted by alexei at 7:54 AM on July 30, 2021
posted by alexei at 7:54 AM on July 30, 2021
@Alexei -- I guess the problem is water-tightness. But at least with the parallel version, one MAY be able to "rewire" them to make them in series? It'd be janky, but at least it'd run.
posted by kschang at 9:58 AM on July 30, 2021
posted by kschang at 9:58 AM on July 30, 2021
Response by poster: It isn't on me right now but the batteries are inserted in alternating orientations so that would mean they're connected in series right?
Up to now I've been using 3 NiMH rechargeable batteries that hold about 2,000 mAh each and the batteries last quite a long time - I probably go a month or longer between charges. If I were to use one of the Li-ion batteries would it last as long? I figure there's something about how the batteries work that means I wouldn't need an 18650 battery with 6,000 mAh capacity to be the equivalent of the 3 AAs.
posted by any portmanteau in a storm at 11:59 AM on July 30, 2021
Up to now I've been using 3 NiMH rechargeable batteries that hold about 2,000 mAh each and the batteries last quite a long time - I probably go a month or longer between charges. If I were to use one of the Li-ion batteries would it last as long? I figure there's something about how the batteries work that means I wouldn't need an 18650 battery with 6,000 mAh capacity to be the equivalent of the 3 AAs.
posted by any portmanteau in a storm at 11:59 AM on July 30, 2021
Assuming you were recommended to use rechargeable AA's in the holder, those usually run 1.2V or 1.25V, so 3 of them in series is about 3.6V-3.75V. Which actually fits 18650 quite well, which has a nominal voltage of 3.7V.
Come to think of it, there's also a 26650 battery, which is basically a thicker 18650 (diameter of 26 mm instead of 18mm) though in practice it's also slightly longer. That may fit better than 18650. The catch is you need a special charger for that.
posted by kschang at 1:35 PM on July 30, 2021
Come to think of it, there's also a 26650 battery, which is basically a thicker 18650 (diameter of 26 mm instead of 18mm) though in practice it's also slightly longer. That may fit better than 18650. The catch is you need a special charger for that.
posted by kschang at 1:35 PM on July 30, 2021
> It isn't on me right now but the batteries are inserted in alternating orientations so that would mean they're connected in series right?
Yes. And 3x 2000 mAh AA would have about the same energy as one 2000 mAh 18650 (because it has 3x the voltage, and power = voltage x current), and a good 18650 goes up to 3500 (and 21700/26650 are even higher). So you're good on that front. But a AA is 50mm long, and an 18650 is 65, so unless the case is significantly longer than a AA, it probably won't fit.
I think it wouldn't be too hard to make a li-ion pack waterproof, though-- since you can charge it through the same cable that attaches to the lights, you never need to open it, and you can seal it up as much as you like. Here's a video-- no guarantees, but it seems like it should work pretty well!
There are also 14500 batteries, which are 3.7V li-ion batteries in the shape of a AA. These might actually work well for you -- you could even put three of them in parallel if you found a holder that fit (and connected to the contacts in your case). Should still be a bit more energy capacity than the original.
Just watch out for fake ones. liionwholesale.com, from what I've heard and my own experience, is legitimate. Ebay and Amazon are not.
Also, all these battery numbers are just sizes -- two digits of diameter and three digits of length, e.g. 18 mm diameter and 65.0 mm length. Makes it a lot easier to understand what's what.
It seems that these battery packs are frequently used in remote-controlled vehicles-- so that might be a good source to look at.
posted by alexei at 6:43 PM on July 30, 2021
Yes. And 3x 2000 mAh AA would have about the same energy as one 2000 mAh 18650 (because it has 3x the voltage, and power = voltage x current), and a good 18650 goes up to 3500 (and 21700/26650 are even higher). So you're good on that front. But a AA is 50mm long, and an 18650 is 65, so unless the case is significantly longer than a AA, it probably won't fit.
I think it wouldn't be too hard to make a li-ion pack waterproof, though-- since you can charge it through the same cable that attaches to the lights, you never need to open it, and you can seal it up as much as you like. Here's a video-- no guarantees, but it seems like it should work pretty well!
There are also 14500 batteries, which are 3.7V li-ion batteries in the shape of a AA. These might actually work well for you -- you could even put three of them in parallel if you found a holder that fit (and connected to the contacts in your case). Should still be a bit more energy capacity than the original.
Just watch out for fake ones. liionwholesale.com, from what I've heard and my own experience, is legitimate. Ebay and Amazon are not.
Also, all these battery numbers are just sizes -- two digits of diameter and three digits of length, e.g. 18 mm diameter and 65.0 mm length. Makes it a lot easier to understand what's what.
It seems that these battery packs are frequently used in remote-controlled vehicles-- so that might be a good source to look at.
posted by alexei at 6:43 PM on July 30, 2021
Response by poster: I was hoping I could just buy the exact thing I need but everything I've seen looks like it'll require some tinkering from me so if I'm tinkering I may as well upgrade my batteries and try to use some 18650s. I picked up a battery, holder and charger from a hobby electronics store today and will first try hooking it up to make sure it works well enough and then go about either integrating it into my existing case or waterproofing the holder. I've got a friend with a 3d printer who'll be able to help with that. If it doesn't work out then I'll just use the battery in a flashlight I've got and buy a 3xAA holder with the positive and negative terminals on opposite ends and modify that.
posted by any portmanteau in a storm at 11:07 AM on August 4, 2021
posted by any portmanteau in a storm at 11:07 AM on August 4, 2021
This has been bugging me and I finally got time to page through 20+ pages on AliExpress. While there are a bunch of different colors and sizes of these things, none have terminals on the same side, or even any hint that anybody would ever want such a thing. I'm inclined to think the piece was specially manufactured for the product.
What I do in this situation is realize this isn't a built-for-life item, fixing this is basically a dead-end, and use Krazy Glue and whatever shaping tools it takes to glue everything down into a workable shape, making sure the springs spring enough to keep things in place (you could also wrap with electrical tape to belt them in). Making the batteries replaceable is optional.
posted by rhizome at 11:27 AM on August 25, 2021
What I do in this situation is realize this isn't a built-for-life item, fixing this is basically a dead-end, and use Krazy Glue and whatever shaping tools it takes to glue everything down into a workable shape, making sure the springs spring enough to keep things in place (you could also wrap with electrical tape to belt them in). Making the batteries replaceable is optional.
posted by rhizome at 11:27 AM on August 25, 2021
Response by poster: Ha, I still haven't fixed it but I'm getting there!
I first connected the 18650 battery in the holder to my light and it worked so I know for sure that if I can just sort out my battery holder/case situation I'll be fine. The new battery and its holder doesn't fit in my existing case though so I had my daughter design a replacement case in tinkercad* a couple of weeks ago and I finally sent it to my friend with the 3d printer yesterday and he'll give it a shot the next time he does some printing. There'll still be a bit to do once I get it but I'm getting there.
Also, I went to a friend's house on the weekend and noticed that he had a charger with 4 18650 batteries in it. I asked what the batteries were for and his wife said they were for his vaping device in a disapproving tone.
*she has no experience with it but she enjoys drawing on the computer and I figured it would be fun for her to work on. She actually spent a fair bit of time playing around with it, which I'd take to mean she enjoyed doing it, except that she hasn't touched it since.
posted by any portmanteau in a storm at 9:32 PM on August 25, 2021
I first connected the 18650 battery in the holder to my light and it worked so I know for sure that if I can just sort out my battery holder/case situation I'll be fine. The new battery and its holder doesn't fit in my existing case though so I had my daughter design a replacement case in tinkercad* a couple of weeks ago and I finally sent it to my friend with the 3d printer yesterday and he'll give it a shot the next time he does some printing. There'll still be a bit to do once I get it but I'm getting there.
Also, I went to a friend's house on the weekend and noticed that he had a charger with 4 18650 batteries in it. I asked what the batteries were for and his wife said they were for his vaping device in a disapproving tone.
*she has no experience with it but she enjoys drawing on the computer and I figured it would be fun for her to work on. She actually spent a fair bit of time playing around with it, which I'd take to mean she enjoyed doing it, except that she hasn't touched it since.
posted by any portmanteau in a storm at 9:32 PM on August 25, 2021
This thread is closed to new comments.
posted by bbqturtle at 12:04 PM on July 29, 2021 [1 favorite]