Build on a Weekend

[Larsb]

EV pouches are great in every way when you can get them, i’ve been running these since some years and the output is great, my variations have been from LG 25Ah pouch in Volvo V60 hybrid pack to Samsung SDI 37Ah from VW, plan on building a pack with LG E78 pouches soon. The power available will never be needed on an efoil though, these cells can output 2-300A easily.

Beware of recalled cells, there have been a number of issues with cells lately and the market seems flooded with warranty replacement cells being sold as good ones. This is the downside, if you buy cylindricals you can easily get genuine, new cells but for pouches there aren’t many options for new, off-the-shelf genuine cells.

[Foilguy]

@vincent
I now have my Fliteboard conversion operational and am really enjoying it!!

I have decided to build another battery pack and am seriously considering using the same cells that you have in your build.

Thanks for all the dimensional info and the case design is a great solution imho.

Can you share what BMS you are using and why you chose a 12S13P configuration?

I’m also interested in if you are using the BMS just for charging?

[vincent]

I’m glad you’re having so much fun and everything is working. The cells are great and have a good price-performance ratio. However, the battery pack must be large enough, as the current output is somewhat low (at least 8p). I chose this big one as it is the biggest possible that fits in all my boards. Since an ESC only supports 12S, I decided against 14S. If you have the option I would definitely go for 14S(more performance, less power). The battery size is a compromise between range and weight. 2kw/h is usually quite sufficient. I have an ANT smart Bms with 300A peak. I use that for charging and discharging. It is ideal because of the 70mm height.
https://a.aliexpress.com/_Eyng2OX
A small charge only is also sufficient. An external model charger usually has a much larger balance current. The Junsi X12 or ISDT X16 are both good devices. Or split the pack into 6s or 7s. The chargers are cheaper there. At the moment I use the R4850 or R4830, R4870. In my opinion, the best charger for our purposes. Adjustable voltage 6-14S and adjustable current. Everything via CAN or Wlan/Bluetooth. 3000W, small, compact 97% efficiency and cheap at 100€. It is really a very good quality, and better than the classic small HP server power supplies. More on this will follow shortly upon request. Very widespread in the DIY PV sector. I am surprised that no one uses it here yet.

[Foilguy]

Vincent

Thanks for the info !

I assume this is the model you are referring to?

I’m also interested in further detail or links to the charger you mention.

I currently have a 12S12P config of 18650 Samsung 30Q cells and I’m getting roughly 1hr - 20km of ride which for me right now is plenty.

So optimal that’s 36,000mah or approx a 7P of the 21700 cells so I think I understand where your 8P minimum comes from. Perhaps this isn’t as linear as this but I’m thinking 10P of the 2170 cells anyway. Haven’t really decided on that yet. Might make a big “explore” pack and a lighter “session” pack similar to what I have now.

Is your case stiff/sturdy enough to allow it to be removed from the board without flexing? I’m careful handling things but I have a family member who is NOT so want to make sure it will stand up to some abuse.

I assume you made the case fit the full cavity in the board and put some type of spacer inside the case to fit the battery’s or did you design the case around the cell layout with no slack and then use spacers inside the cavity of the board?

I also am comfortable at 12S as that seems to work well on my setup and is somewhat safer than 14S if I understand correctly.

Can you explain a bit more about how the 6s packs would work. Ie two bms and then a plugable wire harness to put them in series?

Sorry if these ? are simple but trying to learn on the fly

[th3v3rn]

So I water tested for the first time and blew the ESC. I used the abs housing and used Sikaflex to glue and also bolted it down with tapped holes. I also siliconed the ever living god out of the motor cables coming through the adapter plate.

I think water came through the cables still TBH. What are you all doing for waterproofing? Is dousing in epoxy a bad idea for heat if I am also using thermal paste between the VESC and mast plate?

Also was only getting 40amps so couldn’t get on plane. Need to figure that out with the new ESC.

[Foilguy]

I used the Permatex sealant I referenced above. Messy but seems to work well.

I sealed the hole in the side of mast where the motor wires enter and then sealed the top of the mast where the wires exited. The bottom of the Gong V2 mast has rubber seals between the wire hole and fuselage connection already so I’m quite confident the inside of the mast remains dry.

Let that set up as its messy and I didn’t want to wiggle the wires around much to keep the seal. I think this point is very important to allow the sealant to “fix” itself to the motor wires.

Installed mastbase and sealed that hole and let it set again.

My adapter plate is a bit different, thicker and different hole placement. See photo before I through drilled and tapped for the connector bolts, so my wire hole is directly above the hole in the mast forming a deep chimney for sealant.

Things got really messy from here on as I had to put the thermal paste on and not get it where more sealant was needed. Lots of paper towels, qtips etc but managed to get more sealant in the wire hole and on the threads of the holes and bolts. Get it all together then let it set for at least a day. The sealant is designed for high temp motor gaskets so thicker layers take a lot longer than it’s design spec.

The bolts were short enough that I could put more sealant in the holes from the top side of the plate.

Clean the plate and the bottom of vesc and apply thermal paste and bolt the vesc to the plate.

I have not made a cover to go over the 75200 vesc. I managed to get the whole thing inside the board and secure it with the 4 Flite bolts through the ears of the adapter plate - of course with the orange Flite seal in place. I will figure out a 3D cover for the wire “glob” on the vesc this winter when I can’t foil!
I do not need to remove the adapter plate from the board to transport, just take fuselage off and it fits in my van.

I have had multiple 1hr sessions and the vesc temp has not gone above 31C and not a hint of water inside.

I am so glad to be rid of water cooling through the vesc as it was always prone to a big leak and bad things happening!! NEVER AGAIN!

Lots of aluminum heat sink via vesc, plate, base and mast

Hope this helps!! Great rig once you get it sorted!!

[Kian]

We used Permatex sealant too. We even used an old syringe to “inject” the sealant.

We also used some sandpaper to roughen the silicone from the 3 wires at the place it’s touching the sealant.

It’s all verry messy, but 100% waterproof.

[Foilguy]

The syringe is a great idea!!

The “nozzle” that comes with the tube helps but still hard to control quantity that comes out.

How goes the battery build?

[Kian]

Not started with the new battery build. It will be a winter project.
Looks like we can only get 12 pouches in the box. 13 “might” fix, but no room left for a BMS.

[Foilguy]

Is that a width of the box or length restraint?

[Kian]

For this cell it’s the length as the tabs should not be bend (the cells in the pictures are dead)
3 piles of 4 in a stack.

Length layout:

Width layout:

[Foilguy]

Interesting - thanks for the photos.

Ive done a little reading and some packs were known to expand some during use. Perhaps that was early versions and is sorted now.

Will you use a separator between layers of the stacks and vertically so each cell has a “pocket”?

[Kian]

Not my picture, but they will be stacked without a separator between layers.

[th3v3rn]

Well I have been out a few times and I got to say, I think this is the way to go if you aren’t wanting to build a board. I got a pro flite board for 500 bucks, can’t beat it. Slowly making it better too.

Being able to get some of these parts machines relatively cheap on PCBway is amazing.

[windego]

Why would anyone sell that board for %500. Is that the new carbon pro not classic?

[Jezza]

@th3v3rn

Being able to get some of these parts machines relatively cheap on PCBway is amazing.

How much are we talking for that mast clamp?

[th3v3rn]

Its a series 2 I believe, I think carbon on the bottom fiberglass on the top?

[th3v3rn]

I think 60 machining and 40 shipping? I should have done multiple and sold the rest?

[Kian]

Yes. It was about 60 machining and 40 shipping.

I should have done multiple and sold the rest

That is what I did

[vincent]

The black one on the picture is series 1 carbon Pro. It has the reciever module in the front.