Building 18650 battery pack

EFOIL.builders Electronics (ESC, remote, batteries)
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With some help, I am finally getting around to the last and final step on my efoil journey, building a proper battery pack!

It’s essentially the @pacificmeister build (obviously the older one since it’s using the Parker gearbox). Probably wanting to replicate what @Hiorth did with their battery pack as much as possible.

Questions:

  • What is the optimal amp output I want?
  • Best way to waterproof this?
  • Any other advice or something I’m not thinking of?
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Are you planning on connecting your cells with nickel strips? Will you use a BMS? I’m also building a pack and I’m looking for the optimal set up!

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Definitely using a BMS. Not sure about the strips, that’s a question for the tech guy helping me but I’d say yes just based off what I know about large packs.

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Ok so we’re going to divide the pack into 3 main parts. 12S5P x3. So it’ll have 3 BMS’s. Kinda worried about the ability to kick out 180a continuous and the wires going into the ESC only being 10awg. I guess it’s been talked about on here before but hopefully I don’t have issue.

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Trying to find a plug or inlet for my waterproof case. What is everyone else using?

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Do you have any progress I’m at the same stage as well please provide pics if possible I’m stuck. Lol

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I have terminated the wires in the box itself and use cable glands to get the wires waterproof. It‘s not as quick to dissassemble, but much easier to waterproof compared to a plug.
In my opinion you should have some means of switching the battery off that is not a plug. Huge relay or electronic switch in the battery box would be my recommendation. Please don‘t forget a fuse, in a prototype sometimes those get blown and they are much cheaper than anything else.

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Pack is finally finished! Double shrink wrapped and dipped in plastidip.

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Looks Nice! What BMS did you use and maybe you more photos in the making?

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How much would you say it cost you in the end? Lets not include time as its a ‘fun hobby’ :wink:

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I also built a 18650 battery pack and here is the breakdown of the costs for a 14s14p with Sony VTC6 cells… 42,000mah:
Sony VTC6 cells: 200 cells for 700$
Smart BMS: 120$
Nickel strips and wiring: 50$
10a charger: 50$
You can add another 20-50$ in miscellaneous items like hot glue, cell holders, tape, solder, etc. Grand total of around $1,000 USD. You will need to add at least 100$ if you need to buy a spot welder. Check out my build post to see how it looks like. It is very satisfying to build a battery pack from scratch, but it does take a lot of time and money. Something to consider!

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What weight did this battery pack come out at?

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I didn’t weigh it but probably somewhere around 11kg/24lbs… Expected weight for a big battery pack! I don’t think it will be a problem as Lift also uses 14s14p battery packs which surely amounts to approximately the same weight.

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Thanks @Vicdes2!
I’ve managed to go and find what I think is a pretty decent ready made pack. Could you take a look and let me knwo what you think?

I’m making a wish list to go back to the supplier on like lowering the height and increasing the continous to 80A but all help appreciated

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If you want to order an already made pack from China, I suggest you do extensive research and buy something that was already bought by someone on here. Chinese suppliers might use off brand low grade cells and the pack might not be able to handle the power we need for an efoil. Be careful with that. Also, an 80a BMS might not be strong enough to handle the discharge you need on an efoil!