I’ve learned a lot from this forum and this thread in particular. I’m working on a 12s2p flexible battery with p42A cells. I ended up cutting some nickel strips that I had on hand to create a kind of U shape, then bending it over a 90 degree corner and welding it onto either end of the p groups. Max battery current will be limited to about 40A. I’m planning to do all the series connections with 8 gauge flexible wire/solder (what I have plenty of on hand) and I haven’t decided exactly how to make the “backbone” of the battery, but I have a couple of ideas.
Thanks in advance for any advice.
What you see here is fiber reinforced tape, fish paper, and 0.2mm nickel strip. The cells are also hot glued together inside the wrapping.
Personally, I think this is a great idea if you’re willing to commit to a full series. Also, last thing I’ll mention - I think you (@ShutterShock) could lean on the community pretty hard if you were willing to do the hard work to film it. Combine existing guides with other expert opinion and post the script for all the knowledgeable people here to add/edit/vet.
Talking about views/monetization/etc, if the community came together on a battery building video series like this, I could see it becoming esk8 canon and sent to every new beginner looking to get into it for years. There’s so little high quality content, compared the bulk of youtube, it could be worth the time from a few different perspectives.
This looks mostly good, though you should check the Conductor Current Ratings chart to make sure you have enough cross-sectional area of nickel for 20A per cell. The legs of those nickel pieces look a little thin for that kind of current, though if you are not maxing out the amps all the time them it’s probably find.
My bigger concern is that it looks like you didnt round the corners out on the folded-over section, I see some jagged and sharp edges in that first picture. Maybe go back and make sure there’s nothing there that can rub through the fishpaper on the cells.
This is going to be really really tough for these short little series connections. Bending 8AWG in a tight enough radius is difficult, and then add onto that the difficulty of soldering 8AWG fast enough to not cook the cells, but with enough heat to get a good joint, and I think this a bad idea. I would suggest investing in some 12AWG or 14AWG for this pack. It is going to be well worth it.
I’m not completely opposed to it but it is definitely a lot of work
Something to consider for sure. Problem is, there isn’t like “a guide” persay
@BenjaminF has been mentioning his guide because like 2 years ago he said he was going to make one, written, I think, for DRI. It’s just so much content like he has mentioned
Interesting idea, might be hard to pull off in practice
February of 2021 I made “Part 0” of a complete custom battery building tutorial over on the FreeSK8 forum, which was planned to be many, many parts. That project died when I realized how much time I would have to put into it in order to make it something I feel comfortable directing a noob to and saying “this is all the info you need”. The scope just got way too large to be something I can take on, while also trying to run a business and pay my bills.
I hope to be able to get back to it one day, because I feel that a tutorial of that nature is desperately needed. They have something like that over on Endless Sphere, which I have read through, but it’s not the most user-friendly format or forum, and it lacks some of the safety standards we hold ourselves to these days, particularly for esk8 batteries.
Yep totally makes sense. People don’t know how much time goes into making quality content either lol
Each video I do is probably 20 hours of work at least, and I work full time
It might be worth the time to have a go-to resource of battery building vids, as a combination of my production quality, logical processes, and our knowledge here.
I’d say your audience is people like myself who know how to build a board but unsure how a battery is really put together & thought behind it and would just like to watch and never attempt.
I second this. There’s a difference between overbuilding, and OVERbuilding. Going a bit past the minimum requirement is great. But exceeding it by enough that you make extra trouble for yourself, is not so great. 8AWG is massively too much overkill for a 2p, 40A max battery, and will be a pain in your ass to boot.
Do yall think that putting tape on top of fish paper compromises the abrasion resistance of the fishpaper?
My thinking is this:
If you have something you want to insulate, a layer of adhesive backed fish paper, and a layer of tape over that (kapton, fiber tape, whatever) then a cross-section of the stack of materials would look like this:
Tape
Tape’s adhesive
Fishpaper
Fishpaper’s adhesive
Thing you are trying to insulate
Lets imagine a scenario where the battery got packed in an enclosure carelessly and there is something pressing on this stack of materials while the esk8 (or whatever PEV) is under heavy vibration.
Assuming the tape on top is kapton or fiber tape, then it’s not abrasion resistant. So that gets worn through. Then what’s next in the stack? The tape’s adhesive. That gums up between whatever is pressing on the pack and the fishpaper, making the fishpaper no longer a smooth, low friction, robust surface. Rather it becomes a gummed up, torn up mess, and then it gets abraded through as well. And as soon as a small puncture is made through the fish paper, the fish paper’s own adhesive starts to work against it as well, speeding up the process. Then all that gets worn through and you have a short circuit.
Yall think this could be possible? I really hope not, because I almost always cover fishpaper with kapton tape to hold it down, since the adhesive backing on every fishpaper I have used likes to let go pretty quickly after it’s applied.
The exact likelihood of a weld on the negative pole center isn’t known, at least not to me.
In fact, I’m fairly certain that the majority of cheaper manufacturer packs don’t bother to note that at all.
If I have a weld stray a bit too close to center, then I usually stare at it in mild panic and anxiety, and make sure to not do that again. These days I’ve gotten decent at avoid it, but it’s also important to note that one mistake does not an automatic failure make.
Bad batteries are usually a product of several bad things that add up to an unsafe situation.
so if all my p groups seem fine and are sitting at the correct voltage, does that mean I didn’t blow through the negative terminal?