18650 DIY Battery Holder

Hi

Has anyone here on the forum ever tried using battery holders for their battery packs? You can buy some on ebay very cheap and it would be a lot easier than soldering or welding directly to the batteries. The only problem I could imagine was that the plastic enclosure would melt if the battery overheats, but is that actually gonna happen?

Here is some pictures

Here is a link to the item on ebay.

I don’t know why you would want to use these. It looks huge and would take up a lot more space than your basic 18650 battery end holders. Yes with those you have to solder but the size difference would be massively smaller.

Yes @delta_19 did a build with vape sleds. Some others have used battery trays\holders… search for those terms.

http://www.electric-skateboard.builders/t/10s4p-18650-build-using-vape-sleds/2092

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I am not sure they are going to that much bigger. Well I have not seen them IRL, but I dont think they will be bigger than these guys which also seems to be popular:

I just spend the last 30 min. reading the post @treenutter refered to. Using battery sleds / holders definitely seems doable and easy! Some had a problem with his solder joints coming loose but I think that that is easy to fix. I will probably also need to secure the cells in place somehow, so I am 100 % sure that they are not coming loose. I will do that buy using hot glue at heat shrink.

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what size wiring should be used for a battery is a question with different answers but for sure what’s showing here would be too thin for a series connection but overkill for paralllel

It’s probably hard to get good low resistance connections with these as they likely have to be steel to have a spring effect. end up hotter and greater voltage sag

Thanks for the input. Is it the wires or the “plates” you think is going to be the problem?

I dont know and it might be fine. Not as low resistance as could be for sure though. the connection spring plate things I dont know. people do it and maybe they’re happy. If it holds a connection they’re easy. the wires are surely too thin for a series chain for the battery but the plates are likely ok but the way you wire it you can make all the parallel cells connected with really small wires and just need the fat copper for the series main connections

I am using the sleds in the first picture and they work quite well. I can replace a battery at any time. But i would recommend to spot welt them if you find somebody who has the hardware. It’s much less effort.If you still want to go with them you shouldn’t take the onces with the wires because they would be too thin. get the ones with the pins at the bottom, this way you could pack them together back to back. Like i did for my 12S8P

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I think people need to consider these options more often. They can be much more flexible and you can replace batteries no problem. When you want to replace all the batteries after you have worn them out you just pop them all out and pop the new ones in. So much less work!

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the time for a nice compression pack with low resistance connections and flexibility for the bottom of a deck is 2017!

there’s been really nice compression packs made for bikes that use copper with springs behind but they’re all rigid so wouldn’t work under a flexible board. Someone, somewhere, is somehow coming up with one hopefully. I think about it often and it’d be a great design project with a combination of select materials. But the design could largely be taken from other compression packs for bikes or something. spot welding sucks for conductivity and leaves you unable to check the state of individual cells in parallel. Being able to check each individual cell’s state as you can take them all apart is reason enough to do it. also being able to possible throw all your cells in parallel to balance them would be fantastic. (still don’t know how safe the battery voltage spread can be to do this without harming the cells)

It needs the right materials for structure, probably 3d printable though, and some cad milled copper and steel spring tabs behind it. and it needs to be the complete package with mounting attachments and no duct tape. the more I think about it the more it’s seeming 2017 is the year.

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I agree. This would be a great solution!

What about using flat neodymium magnets (I wonder how much current can such connection handle) and just long enough tube to hold cells inside? Tube with holes for ventilation. And some kind of conductive paste between cells. Loose thoughts…

Awesome idea and I’ve got all the parts to do magnet connections with thin copper sheeting but have been stalling making sure it’ll fit. It’s the slightest bit wider than spot welding but space is minimal for me. Others have had great success with magnets and copper on bikes. wanted to do the minimal soldering of copper sheet to wires between paralleled packs for greater flexibility. So close to making this There’s a long thread on Es and a couple people have done t

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I have access to the tools and things decessary to start designing some new alternatives in battery packs for E boards. I really need to get going on this.

After sleeping on it, I think I actually like this idea even more. Do you think you can find that thread on Endless Sphere? I hope you to see your design soon as well! Please document the process if possible. I am sure that many on the forum will find it interesting.

here’s one thread: https://endless-sphere.com/forums/viewtopic.php?f=14&t=60517

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I’ve actually started reading that long thread @Hummie gave! Got till about page 6 before I got really tired lol…

Non the less, the magnet Idea seems possible, the only concern is how to fixate the magnets in place… Some options were glue, 3d printed enclosure, another magnet (bigger force) or also shrink wrap was used…

Im not sure which method he used at the end but he was very willing to 3d print the ‘‘cover’’ for the magnets.

I think this might be the best - to compress the magnets and now allow them to move around (even if some of them are quite strong)…

One more thing to consider when using magnets - ‘‘regular ones’’ start to lose their magnetism after reaching 80degrees celsius (~176F). So it is better not to ‘‘heat treat them’’ by soldering closely or directly onto them (which will fail anyways, as some users had tried)

Higher heat resistant magnets cost a bit more… and generally, it looked like all of these neodymium magnets lose all their strenght completely at over ~300 deg celsius. / just some fun fact/

I think the heat the magnets would be exposed to could be minimal as you could get super low resistance between cells and the cells themselves don’t get that hot. the magnets do reduce their strength temporarily with high heat as well but I don’t think it’d be a problem with the right design.
I think some testing is necessary to see how thick the copper would need to be for however many amps it’'d need…maybe 50 lets say. shockingly I was just charging my batteries at 9 amps and looking at the bare wiring to the pack; I was literally pushing it through 4 strands of copper. it was warm in the area and it was only a short span but nice to experience first hand.

flexibility under a board I think requires doing groups of cells as the copper isn’t flexible and if anything it will work harden and get stiffer. these packs of cells in parallel, with a copper strip on the bottom and top with the magnets (the details unsure), be pre-soldered sheeting to copper wires between the packs. An all copper compression pack with flexibility. maybe duct tape everything after to hold it in place or a layer of rubber i like. It’ll happen some day.

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the key to making any no-weld battery pack system work is a really good 3d printed battery holder design. I’m liking the idea of springs and copper strips more than magnets, since as others have pointed out heat cycling inside the pack can kill those magnets.

if your 3d printed enclosure has individual channels for the springs and copper strips to fit into, it should perform extremely well and be really resistant to impact. Plus, assembly is just putting the springs into little holes for them in the 3d print and the copper strips along them

possibly base it off an offset holder design like this

and make top/bottom caps that are screwed on and have channels for the strips and springs

of course i’m a glutton for punishment and testing silly solutions that probably won’t work, so what do i know

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