I’ve also learned a lot from his battery-building videos.
1 Like
Hi all! Finally ditched the LiPos, got myself a kweld and some samsung 40Ts.
I’ve been practising on sacrificial cells and I think I got the hang of it. Pull tests are ok:
So I think I’m ready to build my very first (very basic) 12S4P mountainboard pack. It’s going to be brick style, divided into two 6S4P modules. As I want to avoid making any mistakes (and I’m not the only one learning with this project) I’ve designed this 3D printed jig that I wanted to run by you:
And IRL:
Not only it holds the cells in position, but also the “rails” allow you to insert the nickel and hold it while soldering and double as sanity check to avoid the very explosive mistake of putting a strip in the bottom where it shouldn’t. So, before I start soldering away:
- Have you had any experience with these kind of jigs and how did it go?
- I intend to wrap every 6S4P module in fishpaper, but not every single p-group. Should I?
- Would you still hot glue the cells in place?
Thanks!
3 Likes
Looks good to me. Why is the pack in 2 parts? Also if you use cell holders glue or fish paper is not needed imo. Cell holders make packs bigger, thats why there are many fishpaper/glue packs.
Also not to shit on your print but there are injection molded parts out there that do the exact same thing while looking a bit prettier. Doesn’t really matter though of you want to cover the pack anyway.
2 Likes
Thanks! The pack is split due to my absolute hatred for peli cases and my pathological need of matching the top mounted enclosure width with my deck 
Joking aside, I saw @ShutterShock’s video on building a pack with a 3D printed holder (amazing series by the way, learnt a lot!!) and he had a rough time getting the cells in it. A smaller pack is a lot easier to handle this way, but I might try a “full” version since this one was not too bad
Yeah, I agree I’m reinventing the wheel a little bit since nicer holders exist (bare in mind this is draft quality), but I also make my own decks so…
6 Likes
DIY for life!
1 Like
I did a second design for this pack and it was much much better, with a better printer and a different material
2 Likes
I got a friend wanting to upgrade his evolve gt mostly for more range. If we were to top mount the a new vesc, does anyone know how big a 21700 or 18650 pack could be installed in this enclosure when range is most important?
Hey, could someone check out my battery question, i posted on my build thread but i am out of options and do not want to make the wrong choice regarding safety.
This pack is 4 x 3s6p 30q, it was made modular to fit in a few different enclosures. Each pack has a main negative, and ascending voltages through the mt30.
To hook up the bms i plug the packs in series, then hookup the main negative, and connect the batteries to the bms dongle in order. Then plug the dongle into bms.
The pack was charging fine like this in its orignal 12s6p config, prior to the modular build.
Charged to 50.4v volts.
After making adjustments to the series connections to allow more current the pack behaves odd.
The charger flashes at me around 48v, and its a chinese s120 charger with no info. Should I leave the pack plugged in longer? Dispose? Rebuild?
I can tear a battery open to show the welds but i was hoping to avoid that as ive done it a few times already.
Im not suspect of bad cells i wrote the voltage on each P and they were +/- .02
I have tried a new bms, a new charger, discharging the pack (poor choice) and it does not make it past 48v.
Do tell, what’s wrong with 'em?
Got another way of charging? If the charger is fine then a p-group has loose welds or is dead.
1 Like
Yeah i have another charger that is confirmed working as well, behaves the same way. A group might be dead although i cannot detect via multimeter. I guess ill have to inspect all the welds. The first time this happened i measured all of the paralell groups to be very, very close i wrote them on the packs in the picture.
Using a kweld, how would I go about adding 0.1mm copper to an ebike pack that’s capable of up to 400A (12p of p42a). I work with 0.2mm nickel for my builds, Do i have to add copper to all parallel connections or can I just get away with copper on the positive/negative terminals? Would 0.2mm + 0.1mm copper be sufficient?
Need more info.
- What’s the orientation and design of the pack?
- What’s the purpose of adding copper versus stacking nickel?
- Have you done the maths and come up short with the current carrying capacity of a shingle sheet of nickel?
I’ve not done the nickel-copper sandwich myself but imo it’s typically unnecessary as it doesn’t afford any advantages over stacking nickel that are well-demonstrated. There are, however, several drawbacks. Your Kweld will be taxed and at full jules in order to get good welds. This obviously will make things much more laborious. Lots of heat, stress on components and your lipos. It also remains to be seen how the welds will hold up long term.
This might give some ideas but tbh, I think nickel is the way to go until we have evidence that copper is worth the trouble.
2 Likes
There’s not enough information here to give a reasonable answer. How much and where you need to add copper is dependent entirely upon your pack design and layout.
1 Like
stacking nickel kinda went over my head, probably the better move.
Its a 16s12p tower-style pack, split into 2 sides. Using 30mm & 50mm strips to cover the 130mm of width I need to connect the P-groups
a single sheet of nickel is fine for the capacity cells since the max output would only be ~170A, but i wanna know how much more material is required to add if I’m using high discharge cells like p42a’s
It doesn’t really matter what cells you use, but it does matter for how much current you intend to use. Just because your battery can put out 400A, that doesn’t necessarily mean that it will, or it needs to.
2 Likes
The molicels would be used on a higher voltage battery running thru controllers capable of pulling up to that amount
Hold my beer
2 Likes
They ugly. Absolutely ruin the looks of a perfectly good mountainboard for me. They check all the other boxes regarding practicality though.
2 Likes
I used to be in this camp until I used a few of them. Pelicase ftw.
1 Like