New Ground Up DIY for Mark

This thread is about recording a custom build for a fellow esk8er here in Perth. (Thread started 11 December 2017)

Basic specification is

• custom deck - not too flexy
• designed for evolve AT wheels
• desirable 50km range on ATs
• Proper battery back with high spec 18650 cells with 60 cells .
• VESCs for speed control
• EBoardShop fancy Photon remote with telemetry
• Addressable RGB led lights with braking function
• Front lights operated from battery
• Top speed 35km/hr
• Bluetooth iPhone connection
• Smart configurable BMS ( external to board)

First is a bit of design for battery ( range) , motor KV , motor/wheel ratio and vesc basics

 

Have looked at preliminary motor/wheel cog ratios with AT wheels
So basic drive train kit is

• Racestar 140KV 5065 motors
• 15T motor gear
• 66 T Wheel gear
• ATR wheels 175mm diameter

Plugging these into my calculator gives data in table below
- all looks OK with good board speed all the way down to 30V . VESC max ERPM is well below recommended max of 60,000

 

Next is battery type vs range
Intent to use LG MJ1 cells ( after good performance on my other build ) in a 10S6P configuration.
This gives calculated range as below- so all good on battery pack capacity vs. desired range

 

Looks Great Mate, I'm excited to have such a knowledgeable person building my DIY board! This thing will be off the chain! : )

 

Have worked out basic wiring and connection diagram as below

 

A post re BMS and charging
When I de-evolved my board and changed over to VESCs a month or so ago - decided to not have a BMS in the board. A few reasons were:

• Its extra electronics in the board and not really required for discharging due to VESCs having configurable ( with a slow ramp) low voltage cut-off to protect batteries from over discharging.

• On the DIY forums there are numerous posts re BMS cutting out when braking due to the reverse current flow through BMS back to the battery - This would cut all power to the motors and hence coast which is not what you want braking down-hill. The BMS has an unknown performance with reverse current as it is not designed for this - so best to eliminate BMS on discharge path on safety grounds

• With a quality battery pack ( read at least 4P or 6P quality 18650 cells) the packs will discharge and charge in synch - so there is no need to balance charge every time.

So my solution was to wire the balance leads to a 12 pin socket on side of the board and to build an external BMS box.
You can still charge the battery pack through the charge socket on the board OR you can charge through the external BMS .

The external BMS has a voltage digital display for each pack and a combined LCD meter showing voltage , total charging current , charging power and Wh . A normal 10S charger plugs into BMS box for balanced charging.

The BMS itself is a smart configurable BMS ( from PC or phone) but concept would still work with a dumb BMS.

Photos below are of my BMS box - so intention is to build another identical one for this build

 

Mark has chosen the deck

 

I also have new Evolve GT Trucks front and rear along with motor plates and will be running on a new set of Evolve GT AT Wheels (mostly!)

 

Don’t get me wrong here Team, I currently have an Evolve CGT with all the trimmings and love it! This is a passion of mine and I’m really excited about this new DIY Board, not to mention having a true master like Roger Nottage in charge of my build! We’ll keep you updated with the progress, I hope to have my deck, trucks and wheels here next week!

 

12Boards Melbourne emailed me today suggesting the board is a little different...

 

Cool graphic

 

Once again excellent choice of deck Mark.
I think that one is better than the one in the first pic as it is drop through, has less build in drop.
Also interesting to see a battery enclosure in the pic they sent.
Following with great interest
Max

 

G'day Roger, do you have a particular brand/model of anti spark switch in mind?

 

Max - this one - with a quality weatherproof pushbutton/led switch on outside of board
Upgraded Vedder/Fechter Antispark switch 6s-16s DUAL

 

Mark

You know that I can't go-ahead with this unless you renounce the devil !

Cheers

 

View attachment 3184 View attachment 3185 View attachment 3186 View attachment 3186 View attachment 3184 View attachment 3185 View attachment 3184 Board is in and together, all we need now is the electrics!

 

Love the deck profile

 

Second that. It's beautiful!