DIY electric longboard - C6372 - 900Wh - first build

I recently decided to take on the challenge of building an electric longboard. I’ve never owned one and have only ridden one a few times, though I use my non-electric one all day every day. There are a few bumps that I just cannot figure out though. My build includes 4 14.8v 16ah Lipo batteries, a C6374 2900w motor, VESC, BMS, etc (I will put links to my parts below). The main thing that I am stumped on is, the motor says it is 24-36 volts. I want to have two sets of batteries plugged in series, then plug those sets parallel, so I’ll end up with 29.6 volts in the end. I would want to get as close to 36 volts though as possible to get maximum power, right?

Also, can I discharge these batteries fully then just charge them up, or do I have to get a voltage regulator to make sure they don’t go below a certain voltage?

The VESC has a continuous output of 60 ampres , but a max output of 120. I don’t know what that relatively means, is 60 amps enough? I would like to get one to match the motor with 100amps, but I fell like that would be overkill and pointless.

Also, I was planning on only using the BMS to charge the board, not for the output to the motors. With my four Lipo batteries, I would end up with 947.2 watt hours - that should be enough, right? I know it will suck a lot more battery because it has no BMS, but again I’ll probably never use full power as someone who did a similar build made theirs go ~55mph. (although it all depends on the pully ratios and all).

Lastely, I’m not super familiar with how BMS’ work. If I put my batteries in series as mentioned, I’ll end up with 8s (4s per Lipo). Does that mean I have to get a 8s BMS, or will a 10s work? Also, the one. I have below is a 36 volt BMS, will that work or does it have to be the exact voltage (29.6)?

Most of this is dependent on the very first question, if I need 36v to achieve maximum power. If not, them I’m good, but if I do, then I want to try to get as close to that as possible. I don’t want to use 18650’s because I’m not sure how to build them myself and can’t find a good enough pre-built one. Also, these lipos that I have have a much greater discharge rate if needed (for the extra boost).

I hope at least some of the made sense. Thanks for the help in advance.

Battery:

Motor (I don’t think the stats on this is correct, they are 2900w not 3600.): https://www.amazon.com/gp/product/B07FSVKYQB/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B07DNWKS58&linkCode=as2&tag=skatemetric01-20&linkId=c948d644ccd47683c0e5bfd113972766&th=1&psc=1

VESC: https://www.enertionboards.com/electric-skateboard-parts/FOCBOX-programmable-brushless-motor-controller/

BMS: https://www.amazon.com/Lithium-LiFePO4-Battery-Protection-Balancing/dp/B073VMYFM5/ref=sr_1_1?ie=UTF8&qid=1538371882&sr=8-1&keywords=10s+bms&refinements=p_72%3A2661618011

UPDATE:

Now that I think of it, I do realize that I will never need 100 amores for the motor. 60 ampres should be more than enough. I will then need a BMS, but I could limit it to 60 amores, right?

900Ah is ridiculously big and will weigh more than you

I realize it will be large and weigh a lot. It will be roughly 10lbs, but weight isn’t a very big matter for me. Because I am not going to have a BMS, I will need the large capacity, bout this is all still subject to change.

Thanks for you input though.

It will just cause it to not charge properly and damage the battery eventually. It should not make the charge last less long.

I will have the BMS to charge it, just not to restrict the output to the motors.

No, a 900Ah battery will be about 350 lbs

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Haha, my bad. I meant watt hours.

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What is your budget? Do you plan on not upgrading your board? Those batteries are bad. If you go lipo, save money for the future and get turnigy graphene >60C discharge. There are plenty of great battery builders here, depends on where you’re based. I think it’s possible to make work 10s bms on 8s, but safer is just using 8s bms. Do not go cheap on bms, it will burn your house. Choose bestech or supower. Last thing: this hobby is expensive

Can confirm. Very expensive

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Right now, I’m just messing around. For all the parts I have so far (including decks, trucks, other electrical components, etc), I’m at $1,300.

What make the batteries bad? I’ve seen videos with other people recommending them. Also, the pack a large capacity in a small area. I need the power to get 900wh.

I did actually just find a 8s bus, so that Is no longer a problem.

It’s not a hobby for some folks, unless minivan-driving is a hobby for a soccer mom

You’re doing yourself and all of us a disservice by spreading the myth that these can only be toys and not tools.

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Maybe soccer mom’s hobby is being a mom.

Why not Both? But they can be toys. I’ve had cars that are tools But I’ve also cars with only a driver seat, no interior and its sole purpose is to go sideways around corners

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Cars are super-dangerous and kill more people than most other things. If cars were viewed as “toys” by the general population, they’d CERTAINLY be illegal to drive on public roadways.

But, they’re not. The public views them as “tools” for transportation and, as such, tolerates the danger for the better public good.

I use esk8 as my own CLEAN transportation, in place of a car, and other people spreading a myth and referring to them as “a hobby” just means it’s ever slightly more likely that my way of life will be outlawed and thier toy might get taken away. If you call it a hobby, someone else might, and someone else might, and people who know nothing about esk8 will hear that and pick-up that these are toys, which means they are BANNABLE. Because laws are based only on what Joe-Blow-non-Esk8r thinks. Whether what Joe Blow thinks is wrong or not, doesn’t matter. The laws will follow public opinion whether wrong or right. So spread helpful information, not hurtful information.

So, enough with the “hobby” nonsense. I use these fucking things to get to work and go grocery shopping, and I don’t need my way of life outlawed because you use them as toys.

Admittedly, when I still drove a car, I didn’t make my own car…but some folks do

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*staring into a mirror in a candle lit room”

Hobby Mary Hobby Mary Hobby Mary

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I love poking bears. Thier so cuddly.

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don´t take things said too close to you :wink: you just hit in a difficult topic with the words you choose.

Back to your plan. why you think you need 900wh battery? nothing bad with it, but if you don´t need a crazy range there is no need for it. it will just make your board more heavy and more expensive.

a bms will not influence the voltage sag. It depents on the quality of your lipos.

if you run an average board you can easily use a bestech bms with 80A charge and discharge. If you plan to build a MTB and expackt to draw more amps than better no.

…and driving back on course. Can you break down what exactly you are buying. Also instead of amazon, you might want to look into actual E-board sites that sell quality products., @JLabs, @psychotiller, @hyperIon1… hell there more than those as well. Those are just a few.

So put up a list of what you have planned, then let some people scrub that list. It seems like you know where you want to go, so let some of the experts get you there in one piece.

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Have parts from both psychotiller and jlabs. Highly recommend

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