Why not use sillcione? Way stronger than hot glue and can handle temperatures, I have been considering it for some time
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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.
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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
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Sikaflex…never have seen something stronger.
But it’s a mess to work with 
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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?
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I will try it with some old cells, should be way faster to assemble than with silicone
Taking drop test to another level
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Tested with two cells I had laying around
I’m building my next pack with CA glue, really strong bonding, no flex between the cells and way quicker to assemble
What you found is the best method to apply without overdoing? Making a line in one cell and joining them or joining them and put a few drops between and let is spread on its on?
Hey guys,
Thank you for taking the time to give me all those information, they were really helpful!
SInce @neiru37 share his awesome built with me, I changed my initial plans and now I am trying to build a 12S8P battery.
I have been looking on Eboardsperu trying to find an enclosure for a double layer pack, but it seems they only have a 12S4P that would fit my Urban Carver Deck. However, I have contacted Alan from Eboarsperu and he said he is willing to make a double layer version of the 12S4P enclosure( link bellow), only if there would be at least 3 orders for it, so he would cover half of the expenses for the mold. So, if there is anyone interested in such a big enclosure, please DM me? Cheers!
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This enclosure will only work with the cells in the orientation @neiru37 used on his HS11 deck, @vladmrk have already spot welded your cells?, can you modify the packs?
Is there anyway you would be willing to upgrade your deck to an hs11/HolyPro, that would give you an enclosure solution immediately.
With such a high discharge power and weight you are planning to run on this board you might consider this post and take my advise to upgrade the deck:
Hey Alan @Eboosted! Thank you for your reply! I was aware that I had to change the whole layout in order to fit the 12S8P pack and fortunately, I haven’t spot welded the cells yet. I just finished removing all the hotglue and replace it with silicon. Since this is my first build, I didn’t want to go for CA which is permanent, like @PXSS suggested.
Regarding the deck, I am afraid I can’t upgrade to an HS11. That would mean that I would have to change the trucks as well and since I already paid around 2000$ for an Electric Urban Carver, I will end up using only the VESC 6 and the wheels, which means less than 500$. I could try to sell it, but I really like how the carver feels in the urban environment where I mainly use it.
Since I live in Canada and the winter is about to come, the enclosure is not a priority at the moment, though it would be nice to have it. My initial plan was to modify a Trampa underdeck enclosure by adding a 1 cm thick rubber straps between the deck and the enclosure(on top of the rubber gasket), thus creating enough space for the double layers. I could apply the same principle to your carver enclosure. From your experience, do you think that could work?
I have read the tread about the broken carver deck and I understand your concern. I don’t plan to hit anything at 30km/h and if I were to do that, I think the deck will be the last of my problems hahaha.
Cheers mate!
Why do you want such a large battery? I think I have one the largest batteries at 8S13P (1310Wh) on a cruiser but that is so I can ride well over 100 miles on a single charge. Weeks usually go by between charge cycles.
Honestly. If I were to do it again, I would go with a smaller battery. The weight of my battery alone is over 10lbs.
There is no reason to go higher than 6P. If you really want more power, go with a Lipo.
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wow… 100 miles on a single charge?! that’s a lot! Well, I aim for such a big pack for the same reason as you did, I think… more range. I usually bike a lot and I want to be able to do the same tracks with my board. From my calculations, a 12S4P is not enough, not even a 5P, that’s why I aimed for a 12S7P. I assume I could get over 40 miles with it. When I discovered I could get away with 8P, the idea seemed very appealing, but I think I would stick wit the 7P, since it is less troublesome, from the enclosure point of view.
Cheers!
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12s7p is too big of a battery you will end up regretting, the weigh must always be a concern, not only because you won’t be able to lift it but because it’ll be less maneuverable, more mass to accelerate and stop, more time to charge, almost impossible to balance, you won’t use the full discharge potencial, very dangerous it it ever catches fire and so on.
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I am aware that this pack won’t be as simple or lighweight as a 12S4P, but since there are people that have already built similar packs or even bigger, I didn’t saw any reason why I shouldn’t try to built one, especially since I like to be very cautious when building it.
Could you please explain why it would be almost impossible to balance? Shouldn’t the BMS take care of that? I don’t plan to ever fully discharge it, that’s the reason why I aimed for such a big pack… having 30+ miles range should be enough for me, though I think the battery is capable of 40 miles.
Cheers!
one 18650 cell weights 46 grams… adding another parallel to 12s is only a little over 500g… On a board with a person… You are adding 500 grams to 90 kg+… that’s half a percent of the total weight… That’s nothing…
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that’s exactly what I thought… only the batteries for a 12S7P pack weight almost 3.9 kg… comparing that with the most commonly used 12S4P that weights around 2.2 kg, there is a difference of 1.7 kg. My camera weights more than that.
I am more concern about the technically issues like why would be impossible to balance such a pack. I’ve read Micah Toll’s book DIY lithium batteries and watched several tutorial and never heard about this issue. Can someone please explain?
Also, If anyone has some tips about how can I make sure it won’t catches fire or some recommendations for a BMS, that would be great. @bartroosen12 suggested to use a smart BMS, which I am taking into consideration, but if anyone has other suggestion, it would be much appreciated.
Cheers!
On batt safety there some tips here https://www.electric-skateboard.builders/t/looking-for-feedback-on-the-battery-i-built/69287?u=lrdesigns
And use search For boards on fire those threads have a lot of ideas.
About the balancing. IF your p groups got out of balance for some reason it would take forever to re-balance them as the BMS balance current is only like 50ma. On the other hand large p groups SHOULD stay in balance more easily.
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