Some questions about supplies and tools for building a battery

Hi guys,

This is my first time posting, but I have been a long time lurker. I just started ordering everything I need to join the club. I am looking to build a 12s4p or 12s5p battery (after seeing longhairedboy’s trapezoidal design). However I am looking for your recommendations on some of the tools to build the battery. Here is the list of supplies I am looking to buy:

  1. Spot Welder 60 watt station or higher.
  2. Soldering Station (up to 900F or 480C)
  3. Solder (0.025" ? 23 gauge?)
  4. Shrink tubing.
  5. Flux.
  6. Kapton tape.
  7. XT-90 or XT-60 connectors (my dual Focbox vescs are XT-60)
  8. LCD screen to show voltage (more?)
  9. Power Switch recommendations.
  10. Nickel strips (not sure the best thickness). double layered? 15 mils thick / .015 inches?
  11. 10awg superworm
  12. 12S BMS

If you have any places that sell it cheaper or know if a better brand I would love the recommendations! Thanks in advanced!

@longhairedboy can probably build you a battery if you send him the cells. I’m not sure what he charges for his labor. I’ve seen several posts with batteries built by people who don’t frequently build them or who don’t know everything about wiring them up and properly insulating the cell groups that results in a large fire. If you’re determined to build them and get into the business of building them it’s worth it. If not I would highly recommend you leave the very high voltage and very high amp output pack assembly to the pros. I repair VESCs and I don’t even mess with that stuff.

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I am a DIY kind of guy, I like the idea of a pro building the battery but I also like the idea of being able to fix it or adjust it or build another one in the future if needed (thus owning the tools is important). I will be using Samsung 30Q cells, and I think the cost involved is still cheaper than buying a prebuilt battery and I own all the supplies afterwards. I work on all my electronics in a shed that is far from my house and I have a fire extinguisher. :slight_smile:

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I second this. if you seriously think 30mm of nickel strip is needed, just let @barajabali @longhairedboy
build you a battery, it’ll no doubt be cheaper and will make us all feel safer

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I was considering doing what you’re doing at one point, but look up some posts about home built packs, there are plenty that ended badly. Not only were they possibly injured, but most or all of there cells were unusable afterwards.

Okay, that being said, I believe there are a few posts on this forum you can search for that provide a lot of advice on how to properly build these. You can totally pursue this and even make money from it if you build packs and sell them on here. Just due a lot more homework, watch videos, and see if you can get in touch with someone who currently does them to critique your work.

Here’s a link to one of them http://www.electric-skateboard.builders/t/fishpaper-and-cell-level-fusing-use-it/35026

If you are going to be building this yourself, do not get a sunkko spot welder. Go for the Arduino Spot Welder from @aulakiria mine has been great so far!

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Thanks, I was looking at that and thought it would be perfect. I was just wondering if anyone carried them locally in the US. Shipping is very long, 10~15 business days. Also when you ordered yours did you pay a customs tax (in the US), if so how is that done? Thanks for the recommendation!

Can anyone elaborate;

Sunkko 788H vs. Arduino Spot Welder

aside from Size & Portability

I’ve seen and read a bit about Arduino Spot Welder via link above.

I would think the Sunkko would provide a more consistent “Lab” type production over the Arduino Spot Welder being more “Field” type production. Which is why I went with the Sunkko788H. Haven’t used it yet cause I’m still doing my do diligence researching the topic.

Well I just ordered it. I also ordered all my batteries from IMRBatteries.com, so I am committed :smile:

Maybe I can practice on some AA batteries, I just need a 12s BMS recommendation now.

I had a sunkko 709a and now I have arduino. I prefer arduino over the ac welder by far. Cheaper, portable and better welds. That’s my opinion.

I have seen a lot of people having broke their sunkko spot welder (with the pen). The Arduino spot welder is extremely reliable, and the welds are perfect, and you can adjust them for what your doing. I have even seen some people do copper welds with the Arduino. In my opinion they are not even comparable.

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Sunkko 788H : A little quirky, $150 or so on ebay. I would buy the one from the guy in Chicago, that’s where i got mine. It has a lot of heat, more than advertised. If you crank it all the way to 11 on the current and set the pulse to 60 & 2, or 70 & 2 on occasion, it will reliably do .2mm thick nickel, and allow you to weld on top of it with connecting strips. You’ll need to keep the points clean, and they will gnarle some because ofthe heat. However, you don’t need them to have the thin part. Take a dremel and round out the end when the tips finally dissappear and you can keep using them. There is a little quality control issue on these so they may be hit or miss. I have also done some minor mods to mine, i added small copper heatsinks to the arms right by the points, and i soldered in bullets on the mains behind the arms so i could attach the wand from the 709A, which didnb’t work like i wanted, the wand has too much resistance for thick nickel. Also the pressure springs on the arm on mine are trashed, but i found them useless anyway. I always put additional manual pressure on the weld anyway to make sure its deep, which probably causes hte gnarling. Also, you won’t need to buy points and wait for them to come. Just use solid copper wire of a similar guage and round the ends off to a nice round point.

Arduino Spot Welder : I’ve read a lot about these. Thay say you can build one for practically free if you already have the parts on hand, which is not only cheap but incredibly observant and unlikely. You’re going to end up spending money building one of these. Weather ort not its more than $150 plus shipping from chicago is anyone’s guess. I’m sure the comments will be flooded with statements mentioning things like microwave transformers, super caps, slam switches, arduino prebuilt kits, where to get 2AWG wire… but you’re going to end up buying a lot of shit and spending a lot of time. That may be awesome for you, or it might suck. IT depends on your motives. However, it will weld the holy shit out of something, so be careful. They can be tuned to be reliable and produce beautiful welds.

So really its about how you want to go about it. IF you want to build somethign and learn something, i’d say take your time and make your own. If you just want to build packs, maybe just get the 788H.

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Fair enough, I know building an arduino is well out of my scope, but they can be had for a reasonable price.

Now I haven’t even fired this bad boy up to be honest. Still waiting on my nickel strip. But it was only like $100 and I have a spare 12v lying around to juice it.

I know @scepterr has the the same one and looks to be going strong. Hopefully Ill get that nickel strip in a few days and I can report back.

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i ordered that thing months ago and never got it. I may try again soon and upgrade my 709A with it since it has all the framing and mechanicals i need already, and i can probably get the wand working on .2mm nickel if i can get more juice out of it.

I have readed somewhere that the 709A tricks the power circuit in your house, does that happen to you?

Damn, that sucks. Mine came in quick for it coming from EU. Did you ask Malelectrics about it? If so, what did they say?

Either of them will do it.

I have mine on an isolated 30 amp breaker. They require every bit of 20 amps to run, I discovered that when every time i welded, the wash cycle would reset on the washing machine. I ran a seperate line from the breaker box and gave it it own breaker and i was golden. then i discovered that 30 was enough to run the welder and the soldering iron without tripping so now they share that circuit.

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by the time i realized i never got it, it had been months, and at some point i realized it probably got lost in the mail anyway. I’m not worried about it, shit’s too busy.

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Crazy to think that small sort requires such a large current draw. I’m sure there is some maths behind it.

Go with a lower gauge solder if the only soldering you will do is on 10 gauge wire. 23 gauge is way too thin. I use 20 gauge solder and I use it like I am on a sewing machine. :poultry_leg: