It spins

 I wired the throttle, display, and enable to the test controller.  After about an hour of setting parameters in the "bacdoor" app (controller configuration software) I was able to get it to start to spin.  There's more fine tuning to do, but I have movement!

New controller arrived

I just received a second new controller. It's a monster!

First battery build... lessons learned

Here are some things I'd do differently on the next pack

1. The pack needs structure, the wrap is good, but not enough to really give it strength.  It needs something to hold it together.  I really like the plastic cell spacers... yeah the pack is bigger but much stiffer
2. I don't think the pack will stand up well to flight vibrations in a few areas, mostly has to do with the fuse being so small and while they are strong, they can't handle pack loads and vibration.  Where the packs join, it's a real weak spot. Each sub-pack needs a strong less stressed bus bar... I shouldn't have joined them just using fused links.
3. For the parallel bus bars, I want to use nickel strips next time, not copper, less soldering is better.  Welding is much stronger, faster, and simpler.
4. Thicker shrink wrapping

Building larger packs than 200 cells is going to be very cumbersome (and heavy to handle).  I need to re-think some of the logistics of assembling the batteries going into the wings.  They are 480 cells spread out over a meter long on the entire wing, and likely be a bit over 35kg (77lbs).

My plans to build the wing battery as actually 20 serial sub-packs of 24 parallel batteries which can be assembled as they go into the wing are unchanged.  Each sub-pack would (3x8) half-width.  I just think it will need to be wired as it goes into the wing or it needs a way to be inserted smoothly.

All wrapped up!

Okay here it is. All the cells are fused and bussed, all the balancing leads are soldered and stain releived,  the connections were good and the battery balancer is running!

decasing and balancing

To remove all of the rap. Now I'm balancing the one battery which I charged.

encased battery

I forgot to install the balance leads before I in case the battery. But here it is in case it'll all have to unwrapped and rewrapped.

Making sparks

I started spot welding the batteries. I'm using nickel-plated steel soldered to copper bus bars. I definitely like the square plastic pattern much more than the hexagonal RTV bonded cells. The plastic squares are just much more solid.  The plastic also gives some nice standoff for the bus bar to protect the cells from solder heat.  I used wooden sticks on the hexagonal to achieve the same. 

Finally, welding is very participants about the metals.  Aluminum and copper don't weld with settings on my spot welder.  Too low and nothing bonds, too high and it just obliterates the nickel strips.  I know they can weld, just need to find out how.

More battery building

I assembled another pack of 100 from the snap together blocks of 1x3 and 1x2. I'd like to try both to see which one is better and if it really makes a difference. Clearly the size difference isn't important.

Assembling the test pack

I started assembling the batteries today this is just the first few rows.

I 3d printed a cell holder which I use to hold the high temp rtv till it dries.

Here is the bms and wiring harness.