Recommendations on battery building

Build, Repair & Mod
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Hey guys! Francisco here saying hi to all of you! Such a pleasure to greet this amazing community!

For the last months, I’ve been really interested in building an efoil to ride it in the Rio Salado and some lakes we have here in Phoenix AZ.

I already got most of the supplies to make my own efoil (i.e. FSESC, motor, cells, spot welder, remote control, strips, and riffle case, which I plan to use as the board). Besides those, I still need to get supplies like the mast and fuselage, which I plan to do with some epoxy and carbon fiber; and a BMS once I sort out the battery building plan.
Speaking of this last part, I already got supplies for the battery, like battery cells, nickel strips, and spot welder for this part of the project. In this regard I’m kinda lost: I already got my motor, which is a Flipsky 65111 160KV DC Motor 3000W, also a FLIPSKY FSESC 75300 84V High Current 350A, and 168 cells from PAIDASHU 18650 Lithium Battery 3500mAh 3.6V.

I’ve been trying to learn what set I should use with these cells, motor, and FSESC I have before getting a BMS to fit, with no success yet. Like for example, with these specs, I’m not sure how many series and parallel I should use, so I could build a custom made holder with my 3D printer, which btw I plan to build in a combined set AKA honeycomb pattern.

I tried to see some of the content for battery building, but I feel that either some of the specs of the batteries I got are missing, like Amperage, and Wattage, or it’s over my head that I don’t get it yet. Also I tried to use the calculator we have available here in this community for this purpose, without success.

Would someone be so kind to help me first figuring out how many series and parallels I should use given the specs of my supplies, and also given that, what would be the best choice for a BMS for me to get?

Thanks in advance for your support. This is my first post here and I hope to get some help in responses.

God bless you all.

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Hey Francisco,

Did you have a chance to check out my video?
There I tried to explain how to calculate series and parallel cells and all other topics…
Check it out and feel free to come back to me for any other questions

If you don’t have access to any datasheets of your cells you may need to measure them yourself
There are cheap battery testers available, like the one shown in this video

Try to find out the real capacity as well as internal resistance and share here… I have the bad feeling those cells may be too cheap for use in a eFoil battery…

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@Franzapata

Welcome to the forum.:smile:

I see you have chosen an unusual collection of components so far.

Why did you pick the 65111 motor and rifle case ?

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I was also wondering about that
Overkill ESC, underpowered motor…
For a rifle case I think at least the 65161 will be necessary power-wise… and definitely some high-performance cells

My reference values for rifle case:
6kW - 190 phase amps to get out @70kg body weight
7kW- 220 phase amps to get out @90kg body weight
Both with a 1200cm² wing, experienced rider

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The phase wires also exit the front of the motor

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Hey @Franzapata, I share some concern about the paidshu cells you have. I tried to google them couldn’t really find a spec sheet. Efoils demand a lot from a battery and need cells capable of high current. Especially with a barge shaped rifle case. Since you’re in the USA I can point you to a few places I know of to get appropriate cells if you’re interested.
The 65111 might work if you have a large board but it won’t have enough power to get a rifle case up (unless you only weigh ~110lbs, then maybe). You could consider buying a big wing foil board and putting the battery in a box on top of the board. This may end up being more expensive than just buying a 65161 motor though.

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I think its a waste of time with a rifle case. After all that work you will not be satisfied. I suggest look for a used fliteboard board only. They are easy to add custom components and get a professional board as a result. efoiling is a fantastic sport so don’t be worried about the cost too much as its well worth it.

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Hmmm you have had 4 people respond and you logged in 35 minutes ago and yet you have not responded.

I’m starting to wonder if are “trolling” :face_with_raised_eyebrow:

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Hi Ludwig!
Yes, I actually watched your video many times. However, for me it was challenging to both use the datasheet you have attached in it since the batteries I got don’t have any datasheet; so I don’t have the necessary information to feel it out.
In that regard, I think I have the option of returning the batteries, getting a refund, and buying more trustworthy cells, like the Samsung 50E’s are that recommended. Or my other option is buying the device shown in the second video, measuring the specs on the batteries I already got and work with what I have.

What do you think?

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Hi Foilguy!
The motor was in special on Amazon for a very good price compared to other models. Also I researched a little bit and saw that Flipsky seems to be a good brand. Thats why I choosed it. Didn’t think that this model would be a little bit of an underkill as I do now after reading the comments on this post.
The riffle case was my option to go to because I saw that some people in Germany were able to make an efoil out of a riflecase in order to resolve the waterproof component of the compartment. This is the video I’m talking about:

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The rifle I got is a VEVOR Rifle Case 4’ long IP67 waterproof. And last time I used my scale, I got close to 78kg

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Got you! it seems then that my best option motor wise is getting a new more powerful motor then.

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I also messaged the vendor who I got the batteries from and wasn’t really helpful. If you’d like to see the batteries, here they are:

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I saw that there’re some ways to create the board myself too. However, I also say that waterproffing the compartment where electric components go can be a pain. That mostly the reason why I went for the riflecase. I assume that if I’m not satisfied after trying the riflecase for a while, I can replace it for a board, with no big issues. Fingers crossed.

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Sorry, I got distracted by my morning coffee :smiley: but now I’m back.

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Well the description on temu isn’t really very encouraging. I would return if you can.
These seem like basic 18650 cells for small electronics, not high power cells you need. Cells capable of the high current needed aren’t ever cheap and will almost always clearly state the max continuous current they provide and have a data sheet with more details.
If you tried to build an eFoil pack with these and pulled the high current necessary it would heat up and maybe start a fire if you abused them enough.
Check out https://diy500amp.com/. They have quite few good options and some really good sale prices on a few cells. I think they are in Florida and can offer better support than a temu vendor.

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Here is my recommendation about how you should proceed.

Visit a Fliteboard and/or Liftfoils dealer and see what a top branded efoil setup looks like. Even better take a lesson on water.

Here are locations of both in Arizona

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If you have the possibility I would return your cells and get some Name-Brand cells that others here have used

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Cool! I’m also wondering if for this project it’d be better to get 21700 batteries instead of 18650.

I remember to see that Samsung is a brand mentioned in this forum many times as a good option. I’m seeing this 21700 batteries that look promising.

Do they look good for you?

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Cool! I’m also wondering if for this project it’d be better to get 21700 batteries instead of 18650.

I remember to see that Samsung is a brand mentioned in this forum many times as a good option. I’m seeing this 21700 batteries that look promising.

Do they look good for you?