REMB - Raz0r Electric Mountain Board

Found this site earlier, then lost it as it seems I never posted it.  Three hours of Google-fu later, I finally found it again: http://repackr.com/

The site lets you put in your individual cell capacities, and from that it will build a balanced pack for you.  Slick.

The cells have been chilling out fully charged for a 2 months now.  Ryden measured the voltage of each.  The ones which had decayed the most were set aside.  The spread of best to worst for the remainder was only about 0.15 volts, so I'm pretty happy about that.

Ryden then sorted the remaining cells and input the cell capacity numbers into rePackr while I worked on the drive-train.

We are out of time for today, but we should get to finally welding up the packs tomorrow.  Whoot.

<EDIT> Added in some other cells I had to replace the lower cells here, and recalculated the packs.  Average capacity went up to 10587.

Welded most of them together today and drained the battery.  

We still need to go over three of the cell groups again with some more spot welds.  Tomorrow.

</EDIT>

I theorized that the brushed DC motors from the scooters might be biased to run better in a particular direction.  This appears to be true.

I hooked them both up to a supply and compared the audible tone they produced in both directions.  They both ran a little faster in the forward direction.

Craigslist had provided me with one E150, and one E100 scooter.  They look identical in size/shape/specifications, but the E150 motor does run a bit faster in the forward direction.

However, I discovered that both motors run at the same speed when I run the E150 in reverse, and the E100 forward.

Given I will need to mount one of them running backwards, that is a happy accident I can live with.

Now I don't need to go messing with taking them apart to tweak the brush advance.

I have now accumulated about 10 gigabytes of media on this, and have gone much further in the project.

The board was broken down, drive system figured out, parts made... etc.

However.. I'm trying to bring the production value of my videos beyond the one shot, one take, straight to Youtube pattern of the past.  That is going to take some time, and some help, and we don't have it streamlined yet.  

We are working on it.  :)

Stay tuned.

Pricing all the parts for 2 bldc motors, two vesc controllers, charger, etc for what I wanted to build here put me at about $400.  That was a bit high...

I have revised the plan.  Do what I can using what I got on hand, and spend less than $100 total for the missing stuff.

I grabbed two dead razor scooters off craigslist for a total of $24, and bought a bms board, charger, and nickel strips off Amazon fo another $32.

Parts arrived today.  

I have settled on a 10 cell li-ion setup.  That gives me 42-36v for my motors.  I am trying to work 5 cells in parallel into the thickness of the board, mostly.  I plan on building up the sides and carving out the middle.  That capacity will allow me to move to bldc later.

The motors from the scooters are rated 100w@24v, but tolerated 36v just fine.  I will need to watch the temperature of them and I could always just limit my PWM to 75% anyway.

 Time to make some final design decisions and get to work.