@uigiroux Thanks mate! I watched a few tutorials on YouTube and I also ordered a book DIY Lithium batteries… plus with the help of other tutorials that I plan to watch and with your suggestions, I hope I will manage to make the battery. I’m planning each step very careful, especially since it is my first time doing this, but, honestly, I didn’t give too much thought to the settings, yet. If you could please explain more what could be the potential causes of frying your VESC or both, that would be awesome. Or a link where I can find more information would be cool as well. Yup… the price and the shipping issues are the things that pushed me in trying to make my own pack. Plus, I like building my own stuff, so being able to build my own batteries, could be an awesome achievement. Cheers!
Hey guys,
It’s been a while since I posted an update, so here are the 12 packs almost completed. I’ll soon start to spot welding all the cells.
I attached bellow a layout explaining how I plan to do the parallel connections as well as the series connections. For the parallel connections I will use 8 x 0.15T Pure Nickel strips. As for the series connections I plan to use the Trampa cables with their bullet connectors. Not so sure about the bullet connectors though, I just thought it would be a cool thing if I could detach the packs anytime I want… do you guys think I should use them or not?
I would only put them if you really need to disconnect each group, and don’t forget to put heat shrink after connecting
More connectors = more losses and more things to get loose
@Pedrodemio Thanks for the suggestion! I don’t really need the connectors, they just would’ve made my life easier during the building process, but I think I can do just fine without them.
Regarding the BMS, I am still having a hard time deciding between these two:
http://www.bestechpower.com/communicationbms/BMSD328.html
I know that Bestech should be better, but the first one would fit perfectly in my enclosure. I’m pretty sure I could find space for the Bestech one, but it will be quite tight. So what do yoy guys think? Is Bestech that much better that I should try squeezing it in there?
You can definitely get away with a 12s8p flex pack.
@neiru37 I know mate… but I have an Urban Carver so my enclosure is smaller than yours. Btw… where did you buy your enclosure from?
I checked your tread… awesome build man!
I have an HS11 deck (which is basically a holy pro without the holes) that gives me an area of 690mm x 230mm under the deck to mount an enclosure:
Your street carver has an area of 690mm x 215mm:
My enclosure measures about 8 inches, or 203mm wide so I think you’ll be able to mount the same enclosure on the street carver.
I got my enclosure from @Eboosted’s shop: https://www.eboardsperu.com/product/trampa-hs11-holypro-35-ds/
Do not use hot glue. It gets soft at high temperatures and the vibration stresses go through your welds.
I recommend medium ca. BSI brand stuff is my personal choice.
If you really want something with a little more give then try amazing goop or any silicone adhesive sealant. The reason this is better than hot glue is that it can withstand hot temperatures and not come undone yet it is easy enough to undo if you really need to. CA is pretty much permanent unless you rewrap the cells
Actually there’s high temperature hot glue you can use for, well, high temperature applications.
Thanks a lot guys for all the information! Regarding the hot glue, in the tutorials that I watched, no one had specified anything about the type of glue, so I was wondering if it is such a big deal, or can I get away with the standard one I used, since the packs are already assembled?
@PXSS Could you please post a link with the glue you recommend?
@neiru37 Yes, the Carver deck has 690mm between the points where the deck changes its angle, but the sides are shorter, so I only have 610mm for the enclosure. Anyways, I send a message to eboardperu asking them if they plan to do a double stack enclosure for the Urban carver deck.
The problem with hot glue is how flexible it is. Specially when hot, as it does soften a little at temperatures above 60c. It isn’t an issue in most applications but when spot welding batteries, you do not want any flexing between cells as that translates into strain at the welds and eventually the vibrations will break them.
I use CA which is the generic term for super glue, krazy glue, or whatever you may know it as. I use medium CA particularly as it is thicker than standard super glue and gives you a few seconds of work time instead of drying up immediately.
Here is the one i recommend from amazon: https://www.amazon.com/Bob-Smith-Industries-BSI-133H-Insta-Cure/dp/B07GBYJN2G or this one https://www.amazon.com/dp/B0166FFCHS This one is even thicker but also comes with accelerator which dries up the glue instantly upon application.
Good luck with your build!
Why not use sillcione? Way stronger than hot glue and can handle temperatures, I have been considering it for some time
Silicone is also a good choice. The main drawback would be the same as hot glue, it is flexible and not ideal for cells grouped in parallel as most vibrations would affect the weld joints. The other drawback is cure time, at least the silicone that I use at work takes at least 15 minutes to cure before you can even handle it.
It is a much better alternative to hot glue though as it can handle temperature upwards of 200C without any softening or deformation. There are also silicone compounds that are thermally conductive so it helps with heatsinking to a certain extent.
Another great thing about silicone is that it is a sealant (duh) so if used appropriately, you can make your battery packs waterproof. This is the what I mainly use it for.
Lastly, silicone is not permanent. The one thing I really hate about CA is that if you make a mistake gluing the cells, you are SOL as the only way to remove it is to cut the heatshrink. Using silicone for experimental packs helps me in that if I a configuration ends up not working out, I can reuse the cells by removing the silicone. It is a pain in the ass to do but when I got interns that work for cheap, it is cheaper to have them unglue the cells than buy new ones.
I will try sillicone on my next pack, and see how much mess I will make 
I will see if theres any “hard sillicone” avalible to buy that would be great for this pourpose
Sikaflex…never have seen something stronger.
But it’s a mess to work with 
I used heat proof silicon and after 400 km it is perfect! bonding cells with silicon and then with transparent heat shrink it makes the battery pack very firm and in any case for the vibrations I always add a thin layer of foam.
Won’t CA glue make the wrap crack? In my view makes no sense making a rigid connection between wraps if they are flexible and not attached to the body of the cell
What the f, how?
