This is my first emtb and I’m still looking for some advice.
My goal with this build is to make an emtb for long distance traveling/trekking (± 100km/day).
I will be making the battery and enclosure myself.
parts:
(I already have all of these)
-deck: hearo bro
-trucks: apex air
-wheels: mbs rockstar2
-bindings: mbs F5
-battery: 12s12p samsung 40T
-bms: apex smart bms
-esc: lacroic stormcore 60D+
-motors: apex branded flipsky 6384 170kv
-drive: straight cut moon drives
-remote: hoyt puck
what I need advice with:
-battery:
I will be making the battery myself with 10x0,2mm nickel strip.
I’m unsure which fuses to use and where to protect the entire battery pack.
Wether cell level fusing is a good idea, iff yes which fuses
-enclosure:
I want to make it myself out of fiberglass and I already ordered fiberglass from hobbyking.
What resin should I use and some tips about beginner mistakes.
links on where to buy and usefull topics on the forum are welcome
-gear drive:
what grease should I use,
links to buy are welcome (belgium/eu)
-trucks:
The apex airs were delivered with only 6 of the 8 nuts that fit in the channel so I am now looking for the correct name for the nuts so I can buy them. links for belgium/eu are welcome.
I didn’t buy the angle risers that apex sells because they were out of stock.
3d files to print them myself would be nice.
-later on:
the programming of the esc when the fysical build is finished
thats it for now, further advice and links to usefull topics are welcome.
I will start posting pictures later on.
thanks for having me
You can find the file directly on their website, just click the link in the description.
I don’t want to say it’s a bad idea, but rethink if you really need a 12s12p 21700 battery.
That’s a 10+ kg pack and can affect the riding feel quite a bit. If you need that long range, maybe a fast charger in the backpack might be an alternative option.
Should have just messaged them, they could have printed more.
People here don’t seem to do cell level fusing anymore. Sure, your p-groups are large enough that it could work, but I think it’ll just cause more problems than it’s worth. Cells rarely fail in a way where it would actually protect you.
Parts choice is really solid though! Look forward to seeing this built
12s12p its absolutely massive battery pack, if anything I would suggest either 1 out of 3 things, 1 decrease battery size, that battery is gonna weigh a ton or if you are gonna do it so big, increase the series like go 16s or 18s as you will get more out of it that way.
But mainly of all if you ignore all advice above, please go to Samsung 50G or something you don’t need 40t in a 12s12p config, I mean say they put out 30A each cell, 30x 12 = 360A @ 48V = 17 280 Watt from the battery, that is more than your motors could ever pull, also you loose in range as you could have a 5000 Mah instead of 4000 Mah so you loose 12Ah (60Ah vs 48Ah)
So by tweaking tiny things you can improve the build massively, as for fuses I’d reccomend fuse mainly the charge port like 10/12A, I run an Maytech 300A anti spark as it has short circuit protection and works great in general, rest should be fine, also I’d reccomend a smart bms so you can verify the battery groups balance.
If you have the knowledge, check all the batteries with some simple test like internal resistance and capacity, as you could remove lemons nicely if you do so before building.
Thanks everyone but the battery (cells) is kind of set in stone as i already have 150 brand new 40T cells lying around ready to be turned into a pack. Also I already have the stormcore so going for more than 12s isn’t really an option. at home I will be charging at a measly 15A so i guess the fuse will have to be somewhat higher than that. I will be sure to check internal resistance on all the cells with a multimeter. However i don’t have any discharge/ cappacity measuring equipment.
When it comes to fuses I’m just really confused which ones to get because when I wen’t to a fuse selling website there were many different types and most were rated for AC at a specific voltage. I did find car fuses which were DC for 32v and 58v so I’m guessing I should go for the 58v variant. Here I got to my second issue and that is that I don’t know the max Amp pull of the stormcore (60D+). I was thinking of going a little higher for the battery discharge fuse (10/20 A maybe). As for charge port fuse what would you advise?
@Venom121212 I wan’t to go trekking through europe like cyclists do but on an electric board. Also my grandparents live abt 120km away and I want to be able to get there in a single day.
ps.: My parents would get a heart attack if the top speed was anything over 50km/h. The top speed of fifty already took some convincing.
Hey dude, sorry to hear about the nuts but actually they are just M5 nyloc nuts and are super cheap to buy locally.
As for the risers you should have asked, the website was showing out of stock but of course we could have printed more but like @Andy87 said the file is available to print your own.
58V fuses is what you want to get.
My suggestion would be 20A for charge if you plan to charge at 15A (which isn’t much for such a big pack)
and 80-100A for discharge.
Get your fuses from a good source like Mouser. They provide usually graphics where you can check which current over which time they can handle.
consider just doing the positive mold method instead of the positive-to-negative mold method since it’s easier to learn
use plenty of release agent on the mold (PVA or wax, usually)
set everything up you need before mixing epoxy
brush epoxy underneath each layer so it soaks in from the bottom instead of brushing it on from the top
consider using a cheapo vacuum bag system to get cleaner and more structurally sound results. You need at minimum, a 12v vac pump and some tube off of amazon, a plastic bag, butyl tape to seal it up, peel ply cloth, and paper towels for a breather layer. Check youtube for vacuum bag tutorials.
No they are just standard M5 nyloc nuts. Standard truck mounting hardware. Tbh we don’t send the hardware out with the trucks anymore so not sure what happened there.
Killer build i jave nearly exactly the same thing that i am in love with riding.
That being said, ive come to the conclusion that a 12s5p pack is about the very maxiumim amount of weight i want on that board. In full bindings you can hop around and move effortlessly through tight spaces and over things.
Split the pack up into 2 or even 3 batterys you can carry in a backpack. This way your not always stuck riding a super heavy pack all the time.
I will be doing a 12s4p 12s5p and a 12s2p as a reserve spare incase i ran out of juice. All for the very longest of rides.
it’s a good idea but given how I might want to go backpacking/trecking with it. Like how people do with bikes I’m unsure wether it’s a good idea to take away from the space in my rucksack. I also think it would become really heave to carry all that on my back and i’d need multiple bms’s
so i guess the fuse will have to be somewhat higher than that. I will be sure to check internal resistance on all the cells with a multimeter. However i don’t have any discharge/ cappacity measuring equipment.