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Please review my battery pack so I don't make a 🔥

battery
safety
fire

#76

So I can’t just pack the inside of the deck with foam? I really wanted the packs to be easily removable and I think velcro is going to be too thick. Maybe I’ll look for some reusable double sided tape


#77

Yeah, don’t try and just pack it in. Lipos can take compression against the flats, but side forces are really bad for them.


#78

If you don’t secure them, you will tear tabs over time at the very least. Ask me how I know


#79

@TowerCrisis @jasonbhuynh ok cheers guys, I’ll look for some sort of reusable adheasive stuff


#80

I’ll bite.


#81

It’s not too exciting. I didn’t secure them cause “it’ll only be a few rides”. Just randomly lost power while riding.


#82

https://github.com/akhlut/BATT-PCB/blob/master/ParametricStudyofSpotWeldingbetweenLi-ion.pdf

A good read, thanks @akhlut


#83

Lab coats are out guys, suit up! :man_scientist: Lots of interesting info in there. :arrow_up:



#84

I like where they talk about the tips too


#85

Pretty sure it doesn’t matter if you got burn marks on nickel to nickel welds. It’s impossible to make a good nickel to nickel weld without any burn marks. At least for me.


#86

Well its better than nothing but if you read the PDF they talk about what can happen when there are burn marks and what they mean


#87

Is my pack safe/safe enough? This was my first pack… Anything you guys would change to improve for my next one?


#88

Hey @skatardude10 I do like the dual balance plugs one for monitoring and one for BMS!

  1. I couldnt see if you islolated the balance wires from the cells?
  2. You have some white insulation on the positive, what is that? It does not look as thick as fish paper rings.
  3. The red soldered on wires between the P-groups, I would use two smaller gauge wires for the same thing because they require less heat to solder / more flexible / thinner. Or better still braided strap.
  4. Exchange hot glue on cells for silicone for temperature stability in summer etc.
  5. I wish it looked a little neater / prettier :stuck_out_tongue_closed_eyes:

#89

Hey thanks for the feedback! I’ll work on it for my next pack… I have e6000 just didn’t want to wait for it to dry. That’s a good point, 5, hot glue gets sticky easily.

As for 1, I don’t know how well of an isolator electrical tape is, but I put electrical tape above and below the entire path of each balance lead, and where they cross P groups they dont belong to, I added enough fish paper to cover those P groups, below the electrical tape.

2, I am pretty sure it’s fish paper? It’s super strong and hard to tear…

3: good idea, I considered that but wasn’t sure how much current I’d need for the P groups.

5: I like it looking a bit shitty honestly… Probably because I’m jelly of everyone else’s beautiful batteries… I tried to make it pretty but it didnt work out very early on and I just said fuck it.


#90

i used a bunch of electrical tape and kapton. mine looks fugly, but its covered so w/e. first battery probably always rough


#91

Would someone please help me find what’s wrong with my battery? I’ve posted my problem in this thread, but still can’t find a solution


#92

any help for this guy and his charging issue?


#93

I actually like @rojitor’s method of welding a nickel strip to an old cutter blade with different welding times and then look at the bottom of the blade to look at the burn marks. This works very well to find the perfect welding time.


#94

Awesome thread shown the battery porn. Everyone should be using fish paper


#95

30q are only manufactured with flat tops. Button tops are added on (spot welded) by reseller.