Suggestions building modular 14s8p for downhill bike

I'm going to be building a pack for my GT fury and have decided on 14s8p to power my Tangent 6kW kit.



The cells will be new samsung 30Q. The max potential peak would be about 120A (most likely real world may be 100A)

Since the frame doesnt have the typical large triangle to fit a compact pack and I don't want one in a back pack I'm planning on making 7s1p segments that I will connect to make 14s8p. This setup also allows me to use my Hyperion 720i DUO3s charger which will allow me to charge 7s8p out of 2 separate ports at a rate of about .7C which will also help with cell lifespan to some degree (500W out of each port).

Since this setup complicates pack efficiency a bit (according to all I've gathered from reading) I need some advice given the design parameters I've outlined.

1) which connectors should I use to connect the the 7s1p packs to make 14s1p? (Minimize V drop)
2) which connectors should I use to connect the 14s1P into the final 14s8p pack? ( I can coat connections in silicone to water proof)
3)I'm thinking of using 10awg copper stranded wire for my connections. According to the http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=3.277&voltage=52&phase=dc&noofconductor=1&distance=.25&distanceunit=feet&amperes=120&x=0&y=0 the voltage drop at my theoretical 120A max and a 52V system and ~4" wire at connections I might see a 0.06V drop. Is this a reasonable awg of wire?

I will attempt to keep all connections to the main +/- at the same length etc to limit differential load sharing.

Obviously there are compromises with this setup but that's what I'm working with To make this DH bike an UH bike Any advice to help me make it work is appreciated!

XT150 connectors should be fine for the high power connectors i have used the XT90 and they have been fine for the 80A i tested not sure what wire size works with XT150 there are other ways to use XT90 at 180A but i cant publicly recommend that

Thanks I'll look into the XT150s

The 150's or any good 5mm or bigger connector will work great.....speaking of great these are just that, http://www.castlecreations.com/en/accessories-5/castle-connectors-6-5mm-011-0053-00

On my 24s15p pack I built I originally set up so I could use my Thunder Power 820 charger prior to getting a Addapto MaxE. It was 3 separate 8s15p packs connected by 5mm plugs. Pulls 200 amps peaks with no heat that is distinguishable by feel.

I envy you on the Tangent drive....that thing is freaking amazing.

If you were close I'd help you build the pack.

Tom

Nice pack!

Looks similar to what I'm considering. What cells did you use?

I wish I could take you up on the offer lol. I'm located north-western Canada.

I used VTC3 cells which is low tech now days. For the Tangent any good high capacity cell is your friend like Samsung 30Q or Sony VTC6 blah, blah, blah. Easy to peak what you need for your motor.

I saw you were not close.

Good luck with the build.

Tom

120A peak is nothing for 8P. Tesla cells can do that.
Your pack construction/welding becomes most important at the high current / cell levels.
I sent a PM

okashira said:

120A peak is nothing for 8P. Tesla cells can do that.
Your pack construction/welding becomes most important at the high current / cell levels.
I sent a PM

Click to expand...

8P tesla cells should not go over 80A peak 40A continues if you want them to last

I have a 14s7p and I pull 150 amps. 21 amps a cell.

At full speed full throttle I am pulling 45 amps @ 34mph. I am running 2x 750 brushed motors and my motors overheat be for my batts over heat.

So yes you can pull 15-20 amps per cell on Tesla cells. No you can not pull it for too long. Yes u need to monitor temps (i use my hand)

Eric

Use 2 xt90's...lol...

8 gage would work....

Finally did a vid of the bike and bats

https://youtu.be/oQVqJy7xjdo

Eric