The battery builders club

[Pecos]

I think a lot of it has to do with not being lazy - it shouldn’t be the first or second option for higher current paths and i feel imho it is used instead of better methods because of poor planning or trying to save money/time using methods that are perfectly appropriate for different applications - Not having a welder that can do thick narrow strips so stacking thin narrow strips is not as good of a method as using wider nickel or using a more capable welder.

There are places you can cut corners- like stacking a small strip to make balance lead connections cleaner and flatter - that i think are perfectly fine. But not using the correct rating series connection because you want to be done now with the stuff you have is poor practice and shouldn’t be encouraged especially with new less experienced builders who maybe haven’t thought through all the consequences.

Just my 2¢ but a blanket “stacking nickel is fine” is bad advice and a better way would be “where are you stacking and why” and here is where it’s ok vs not ok

[PedroMcJimenez]

Hey thats a much better explanation than “dont stack nickel cause we have beef with hummie”
Yes theres times and places that call for it, many pros have without issue.

@Pecos

stacking thin narrow strips

This is definitely not the place to stack, but no one really uses thin strips around here anyway, especially not for series connections.

[jack.luis]

I appreciate you taking the time to write out the thoughts that I wasn’t willing to write out.

[Evwan]

New Samsung 30T 21700 3000mAh 35A Power Battery

Samsung 30T $2/cell
Similar discharge characteristics to molicel p45b (sag), but with 2/3 the run time. Good for a budget race board or a small pack.

[TheBoardGarage]

Roast me.

[jack.luis]

Giving you a thumbs down for consistency

[Pecos]

Gonna say, you did this because lazy or cheap or impatient… or all three? will probably be fine but not the best. I shake my head at you in disappointment

Also welding to the center of the neg?!?! Didn’t see this when you posted on telegram lol.

[TheBoardGarage]

@Pecos

you did this because lazy or cheap or impatient… or all three?

Neither. Never made this pack layout before, don’t have any other nickel that will do what I need. So I cut existing pieces to suit and will see how it goes.

I currently exist at a point in my work where I’m well beyond hundreds of packs, most of which were all the same, and it doesn’t make sense to have a custom shape cut and ordered in quantity for a prototype of something I may not even end up producing more than 2-3 of.

Between all that, and the last few years of running this shop, producing in larger numbers, doing repeated testing, making new types of tests to suit the stupidly niche stuff I have to make, etc., the perspective of what’s practical, impactful, or just conjectural, has shifted a good amount.

[Pecos]

Seems to fit impatient and cheap but not in a critical way, more in the good enough is good enough way. A thicker strip (this is .15? by aprox 12-15mm) and wider would have been better imho 20mm by .2 would be 45ish amps continuous and taken all the real output a 45p can dish as 1p.

This is not the same as some garbo batteries ive seen on reddit and other places with 3-4 layers stacked to get the amps or mixed nickel and plated steel lasagna used.

Would you say this is your first choice method if you could have any materials you wanted? Probably not is my point

[TheBoardGarage]

That essentially illustrates my point in the last bit.

@TheBoardGarage

the perspective of what’s practical, impactful, or just conjectural, has shifted a good amount.

^There is a LOT of conjecture about numbers, and I’ve been positioned in a way over the last couple of years to specifically front a massive amount of it as the DIY one wheel space rapidly expands.

That kind of conjecture is largely based on numbers that exist on paper, but don’t get revisited in any appropriate practice that yields actionable conclusions.

It’s the same kind of thing as “so this 2p P45B pack is a 100 amp battery” or “the 50S isn’t a good cell, because it’ll wear out in less than a year and it runs hot.”

It doesn’t really amount to much, because reality ends up as the wall against which the conjecture falls apart.

In that stagger, where would one fit a 20mm wide piece? Is the pack going to experience a current draw that would warrant thicker nickel? If so, what kind of heat will the entire pack experience in the sealed enclosure packed like a sardine can?

There’s more, but either way, as I said, the sheer amount of collected information from testing and in-use data shows very different things from a lot of the theoretical “better” type of things I’ve come to believe less and less.

You can call it cheap or impatient. But in the context within which I and my work exist,
I can’t say I agree.

But I did say to roast me, so, fair game.

[Pecos]

@TheBoardGarage

Never made this pack layout before, don’t have any other nickel that will do what I need. So I cut existing pieces to suit and will see how it goes

This statement is where i got my critique from. You did ask for a roast and im not really interested in an argument unless you are having fun too so know im just here to hash it out for fun. Not trying to prove you wrong or call you names except if it’s light hearted and taken as humor.

I know nothing more about your use case except that it is an eskate forum and eskate usually needs amps and vibration resistance in the smallest package possible. What are your requirements?

I’ll admit that i don’t know much about ow applications and also that you don’t need to make an ebike or battery bank to the same rigorous standards. Imho every custom battery should take into consideration the application. No laptop needs p42a or 50s cells but I could be convinced if you had a use case.

Im sure you make good quality batteries that are built to the requirements of their use. And im sure you have built up an intuition about what is required for a battery to last from all the work you’ve done and can decide when enough is enough.

@TheBoardGarage

where would one fit a 20mm wide piece?

Fair point, because of the staggering it won’t fit. Im sure you have a reason to stagger instead of making it over under with the staggering but having the nickel folded into a 90 degree bend.

but not knowing why it’s in this arrangement but assuming it must be in this arrangement, and assuming you need more capacity than one strip can provide so you stacked two equal strips bla bla bla…

then why did you not use one thicker strip, is it because you didn’t have one? Or is it that you prefer to stack nickel?

The amperage ratings of a quantity of nickel/copper with a given insulation is all quantifiable - what is more nebulous is the actual requirement for use and what the tradeoffs you opt for are.

Wish my infrared camera hadn’t been stolen i would totally smoke a test battery for science. It would be really interesting to compare methods that are assumed equivalents

[TheBoardGarage]

@Pecos

You did ask for a roast

In fairness, I still haven’t gotten one. I assumed something like “get that cheap monowheel horse shit out of here you FM fanboy”.

@Pecos

What are your requirements?

No idea:

@TheBoardGarage

prototype of something I may not even end up producing more than 2-3 of.

@Pecos

then why did you not use one thicker strip, is it because you didn’t have one?

@TheBoardGarage

Never made this pack layout before, don’t have any other nickel that will do what I need. So I cut existing pieces to suit and will see how it goes.

I’m not likely to use 0.3mm and cook the welds and cells (and that’s absolutely something I’ve tested a great deal) just to theoretically satisfy the sacred current chart. That’s silly.

I consider onewheels eskates also, so, that may run counter to my claims that I have decent judgment.

Professionally speaking, I’ve just seen, tested, destroyed, and done so much, that I’m at a point where I feel like the crotchety old man that’s just tired and wants to get on with the reality of the job.

Specific to the pack, it’s a 30/31/32s1p that has to fit in a BadgerWheel TORque box, with a 2-piece BMS. There simply isn’t a way to make that wiring happen with that combover nickel flap you showed.

Just has to be a straight line.

Regarding the nickel stack itself, I simply haven’t seen evidence to suggest that it’s inherently failure prone. Even if one is meant to just take the usual wisdom at face value, the welds of both the cell-contacting nickel and the nickel-contacting-nickel tear, destroy, and leave holes in the nickel, with their remains still on the can, when pulling the conductor off.

As for heat testing, or any testing, I have equipment. I dumped more money into equipment and materials than I’m still comfortable admitting to myself. All under some grand illusion that I was somehow contributing to a greater good and wealth of knowledge and all that. But over the last year or two, I’ve further met with the realities of this hobby, its participants, and its economics, that I kind of just…don’t care about convincing anyone of anything anymore.

So, this pack will have stacked nickel. And it will probably work fine. And if it doesn’t it will join the very large pile of junk that has left my garage over the years.

/selfroast

[glyphiks]

@TheBoardGarage

don’t care about convincing anyone of anything anymore

Yet here you are, still sharing your sage wisdom. Thank you kindly, crotchety old man.

[TheBoardGarage]

@glyphiks

Yet here you are, still sharing your sage wisdom

The me from a year ago probably would have written a few paragraphs more. Progress of a sort, at least. I’ll save the longer stuff for where I can run AdSense.

[OzzysPaw]

Trying to build a 16s5p samsung 50s using 6p precut nickel. Beyond cutting it down to 5p, I’m alternating the cell arrangement like you see in the drawing, but that also means that I need to cut the middle group’s nickel down so that it doesn’t over lap the next group. I plan to set the max battery current around 100A total and average probably closer 50a total.

Am I good cutting the just middle nickel piece down or should I try to cut all the nickel to be the same size?

[Battery_Mooch]

@OzzysPaw

Am I good cutting the just middle nickel piece down or should I try to cut all the nickel to be the same size?

As long as everything fits and nothing is getting too close to touching something it shouldn’t, you want to have as much nickel as possible. That lowers the pack’s overall resistance (less voltage sag) and helps to spread out any heat.

Don’t worry about cutting away nickel you don’t have to.

[OzzysPaw]

Thank you, Mooch! I wasn’t looking forward to cutting down more than I needed.

[b1996]

at this point people believe that 10A cell from samsung is magically better than a 10A cell from EVE or whatever, and it’s kinda sad cause i’d rather take a good EVE or Tenpower cell (Eve 40P or Tenpower 40TG)

yes you won’t get the range, as far as range ánd power goes, 50S is probably the best option

[rosco]

Ok so weld tests with new kweld (thanks @glyphiks !)

0.2 nickel 50j
A couple sparked maybe because of poor contact I think, but do these look too hot? Think the end of the battery bent a bit when I ripped the nickel strip off it

0.2 nickel 40j

40j was still plenty difficult to pull off with pliers and leaves torn nickel shards on the can….

Comments / advice please, battery gurus.

[glyphiks]

40J looks good, you probably wanna put a little more pressure on the probes.

Not sure what cells they are or how they weld, but in my experience, molicel usually need a little more energy than other cells to get a good weld.

Also, what angle are you holding the probes at? The angle will definitely change the quality/consistency of your welds, so experimebt with what works well