Nice work, what’s the final weight of your battery ?
I posted the weight before, but don’t remember. I’ll weigh it and get back to you. It should be about the same weight as lifts battery. 14s14p.
I looked back in the tread and previously posted that the acrylic case weighed 8lbs by its self. Which put the total battery weight over 20lbs / 10kg.
However that case had 1/4" top and bottom. Now I use 1/8" top and bottom. So, it’s lighter. I will weigh it and get back to you.
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@Flightjunkie Cant find in this thread if you glued the box together, of if you only used the 3M tape?
If glued. How are you planning to open the “lid” if maintenance is needed?
Any info appreciated.
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Sides and bottom are glued. We used 3m vhb double side tape to attach the top/lid. It’s fairly easy to remove the lid with a razor and rubber wheel to remove residue. We have opened our battery boxes numerous times now.
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Hi.
Yes. Like Sean said.
Google how to make a fish tank out of Acrylic. The glue is a very thin liquid that creates a chemical bond where the two parts become as strong as one.
The lid is held on with 3M VHB double sided tape.
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Thank you @Sean and @Flightjunkie.
Yes. I’ve glued stuff like this before, but it looked on the pictures that you used the 3M tape at the bottom too. My mistake I guess 
Soon there will be a clone of your pack here in the Netherlands.
I’m still not sure if this is going to be a 6S or 12S version. Going to do some tests today to decide.
Awesome. Post your build! It will be good to see!
It’s glued. Yea, looks black. The fiber optics of the plastic shows the black 3M tape from the top.
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What about adding a 2nd bottom plate with some space in between the two plates and running water through it for extra cooling? Would this be a good thing?
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Sounds over engineered to me.
With 14 cells in parallel my battery barely gets warm.
My 6 x 6S lipo’s (all in parallel) do get warm (40C), but than again I have a jet board with about everything double in it than what you flying people have.
2 ESC’s, 2 motors, 2 jets… and way more drag as I’m not foiling.
The new jet board I am building at this moment will have 12S12P and should be fine when running in normal mode, but if I ever decide to go bigger than 12S (can go up to 16S), than for sure cooling the cells would be a nice option to have
Hi.
Ah, yes. Jet board is much more current demand.
I recommend 14s as the safe voltage limit around water. Even 14s can be fatal. More dangerous in fresh water then salt water. Be careful.
Add the extra cells to the parallel group. 14s16p would be smarter.
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Question… Do you hook them together (in series) externally or internally (ie: inside the box)?
I guess externally, but thinking of this, you could theoretically keep them hooked up, and charge them as 2 7S14P’s …
That is as long as you have 2 different balancing connections… 8 for the 1st 7S14P and 8 for the 2nd 7S14P…
Or… Am I (again) completely wrong here?
We kept them as 2 seperate 7S batteries, each with its own balance lead. We then connect them externally. This allows you to use the X8 charger.
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Hi.
They are internally, permanently wired as two 7s14p batteries.
They are wired externally as two 7s14p batteries for charging.
Then for use, they are wired externally as one 14s14p battery for use.
I have posted many pictures of the battery and the wiring. If looking at the pictures doesn’t make sense to someone, then please keep reading about Lithium batteries. You need to understand parallel and series connections, balance charging, the dangers or Lithium batteries, and relationship between load and voltage drop (for calculating wire size).
These batteries are extremely dangerous. Please be careful.
This is a great website to learn more.
BU-302: Series and Parallel Battery Configurations - Battery University.
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What amp rating did you use on the fuse wire, and what thickness were your copper bars?
Hi.
The information is all here. Let me find you some links…
Bus bars are made from 10awg solid strand copper available without insulation at the big box hardware stores. The reason for the 4 cross bar configuration is to keep voltage drop under 3% at 200 amp load.
Let me know if I can be of further assistance.
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Do you not find the fuse wire generates a lot of heat when its running at 10A?
Hi.
I have detailed all of these things in this thread. As shown in the link provided in my last post (see quote attached below), the fuse wire does not exceed the temperature of the battery cell at a continuous discharge rate of 10 amps. As shown with thermal imaging.
I am now running two of these batteries with my VESC limit set to 200 amps and with several months of heavy use I haven’t had any issues.
Sean also runs this exact battery build. And so does Eric. So, that’s 4 batteries so far. And I’m gearing up to help some more friends build them.
Excellent design and performance. Maybe one of the few batteries that can provide 200 amps continuous? All 6AWG wire. Very low (none) voltage drop.
Hope this helps.
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Hi,
Thanks so much for your sharing.
I am a newbie who would love to make an efoil for myself.
I wonder why don’t you trust BMS?