Rebuilding commuter board 5" Skikes, 18650 konions, VESC

Hi guys,
I am in the process of reworking my commuter board and since I did not share the build process, I thought I might at least share the rebuild.


The specs now:
3x2s Zippy Compact 5.8Ah
Alienpower 7s 120A Sensored ESC
Alienpower 5065 270kv Sensored Motor

195mm Paris Trucks
5" Skike Wheels (modded)
~80cm Deck lenght

Custom split aluminum enclosure
Turnigy 'poor man's BMS'
Wiiceiver+Nyko Kama

Charging/Balancing via 9pin DSUB connector
Switches for light, 'bms', antispark, EC5 Loop as main switch

Problems with the current setup:
Don't want to leave lipos charing unobserved
battery tends to unbalance
battery cant be swapped easily , I don't have a 2nd one
enclosure is not as enclosed as I would like
shitty griptape (minor problem, but still sucks!)
messy wiring so I never want to open the enclosure again for checks
I am scared of inbus head bolts stripping


Things I want to change:
switch to 18650 konion cells salvaged from makita packs bought from doctorbass
make an easily swappable battery 'ebike style'
get rid of the poor man's bms
change to VESC for testing
get rid of the EC5 loop, momentary switch and bms switch
add a proper switch when back in stock at APS or vedder develops one
change to XLR 3pin plug for charging
swap some of the higher stressed bolts to TX

Rebuilding the enclosure

I will be making a two part enclosure, one part containing the batteries and charge (xlr) and discharge (EC5) ports, the other one containing VESC and other stuff being sligthly larger so the battery one will slip about 2cm inside and connect the discharge port. The VESC enclosure will be permanently fixed to the board, the battery one will attach via clips to the VESC one and the board and be interchangeable on the go.

The battery enclosure will fit 24 cells in 6s 4p config to allow 40amp burst current, so about 1kw from that motor (which is enough power for a commuter imo). It will only offer 200mAh more than the current battery (which probably gets negated by using used cells) but I will be able to carry a 2nd or even 3rd pack in my backpack for super long range)

For the material, I see three options:
glass fibre
wood
abs

I tried glass fibre, but without a strong vacuum equipment, it will get uneven corners (check the upper left on the router pic below to see my gf experiment with wrinkles) where the fibres fold over and I need a clean outside surface to fit the stub end of the smaller enclosure into the ESC/Electronics one.

Abs requires an oven and i do not have it handy.

So I ended up shaping a wooden enclosure around a mold with a flush trim bit and angled plate on my router. After the mess I made in my workshop, maybe getting an oven or vacuum equipment would not be too bad at the end.. will see how the result turns out.

Slightly oversized 3mm plywood sheets were attached to the mold with double sided tape and trimmed (no sheet on in the pic).

Covered the mold in kitchen cling wrap to protect it from epoxy. Forgot to take a pic, but added strips of GF on the corners to make stronger joints.

Everything taped up and drying, will see how it turns out tomorrow.

Will probably cover the enclosure with thin CF just for a little stability and looks (just like the board).

What do you guys think?

Two things I am not sure about yet: What is the pin spacing for the JSt connectors on the VESC and the sensor wires of the 5065 270kv Alien sensored motor. Can anyone tell me?

About the jst connectors: they are JST-PH 2mm spacing, I don't know about the sensors though. I like your setup, need to start with something like this as well!

May i ask what mods you did to the skike wheels to make them fit the axles? i know my axles aren't long enough.
i've got a set here waiting to go on and i can't decide on modding the wheels or the trucks.

Cheers

elkick said:

About the jst connectors: they are JST-PH 2mm spacing, I don't know about the sensors though. I like your setup, need to start with something like this as well!

Click to expand...

Thanks! All those different jst connectors can be confusing and it is a pain to have to wait on that one stupid plug that just won't come in the mail.

About the sensor wires: They are JST ZH 1.5mm spacing 6 pin connectors. There are not as many of them on ebay (at least in Germany), but rc model shops seem to have the cables. I wonder if it would be a better idea to cut off the flimsy connector and solder on the jst ph 2mm spacing plug for the VESC. But the motor side wires seem to be attached to some PCB which the plug is soldered on, does that matter or is it just for mounting the plug? I'm not sure.

killisch said:

May i ask what mods you did to the skike wheels to make them fit the axles? i know my axles aren't long enough.
i've got a set here waiting to go on and i can't decide on modding the wheels or the trucks.

Cheers

Click to expand...

The wheels were trimmed down on a lathe so that the overall width of the rim is alike to those of skate wheels. Then the recess for the bearing was bored out accordingly. You can keep the bearings but need a new spacer or shorten the existing one. I had someone else do the lathe work 'cause I don't have access to one. He had to make an adapter to get the rims properly attached on the lathe, but the rest was probably easy. I don't know how difficult it would be to change the truck to fit the nonmodded wheels, but I assume modding the wheels is easier.

Took the enclosure from the mold today, seems at least as sturdy as the 6 layers of GF (even when the GF is not trimmed yet).

Covered it with unidirectional CF afterwards (forgot to take a picture) which worked ok, but I wish I had a vac setup for that.


Took a look at my programmer from ebay, turns out it has only 4 cables (could have seen that one coming..). Someone over at vedder's chat told me it should be fine and I would only need SWCLK, SWDIO, GND and 3.3V pins for the programming. Too bad it won't fit the 2mm JST Ph plugs on the VESC, so I will have to wait.

Installed Ubuntu on dual boot on my old laptop (took some time but worked in the end) and put in the commands from vedder up to the relog. Could be that not everything worked since not all commands seem to actually do something and I think one returned some kind of error. Will have to see once it is all done and I got the program cable. I think I read somewhere that dual boot might not work for the BLDC tool and programmer but I can't find that post again, so here's hoping it will turn out well.

Did some test soldering on busted cells, this will be the 'end' of the series of 6 sets of 4p, poles for further sets will alternate so the copper spans 8 cells in each go. Cells will be held together by the copper sheet, hot glue and power tape.

I was told that 20mm width of that copper sheet should be able to carry 40 amp, so with about 25mm width it should be fine. Soldering worked on, first putting solder on the cell tabs, then pressing on the sheet and applying heat from above. maybe it would work better and make a stronger joint if I drilled a tiny hole (1mm diameter or so) into the copper sheet right above the cell tap to allow solder to fill it. What do you think?

While the wooden case worked out well, it had the same problems as GF case after I covered it with CF, so no clean edges anymore due to folded fibres there. Also, it turned out to be a pain to trim it to the right height. Trimming the plywood around the mold with a router made quite a mess and always had the danger of demaging the mold.I need it to stay intact so I can make multiply exactly same sized battery boxes). So I switched to vac forming ABS, check this topic for info: http://endless-sphere.com/forums/viewtopic.php?f=35&t=70553&start=25#p1071072

Haha sweet build furp. Surprised I didn't see this thread. Nice molds. Pretty much how I made my original mold as well.

Finally got back to this project and made some progress!
Built a professional trimming table to trim the vacuumed enclosure to the right height. I used a bigger diamond sprinkled metal disk before, but it seemed to have some wiggle room in the special holder so I ruined the first enclosure by trimming it too small. Second one worked better, put the enclosure on the flat side and slid ot on a mdf plate along the trimming blade.


While I was originally planning to go 6s4p, I changed my mind and am going 7s 3p now, even tho it will give less capacity and amperage, but can be charged with a 24v liion ebike charger which is a big plus. I noticed that there are some ebike charing stations around, basically a locker with an outlet inside, but the power only comes on once the door is locked, so I needed a plug and play charger instead of my 6s rc one.
Started building the battery by glueing the 3p groups together, making sure that there is always a layer of hot glue between the cells (not that important on parralel groups, but on series ones).

Put the parralel groups together with changing polarity of each group, so I can connect 6 cells at once with a single copper strip (except the + and - pooles of course). Same hot glue method with lots of glue and a few rounds of powertape for good measure. Cut the copper strips and made small indentations to mark where to tin the strip. Tinned the nickel of the cells and the copper strip, then put the strip on and heated it enough (some extra solder on the iron helps) to solder strip and batteries together spot by spot.

Added discharge cables (10awg is way more than needed but I had them around) and balance cables, even tho the battery should not need them, but for the first build it wont hurt to be able to check parralel group voltages. Some meters of power tape and a bit of plastic form a water canister later, it looks not too bad and feels sturdy. Turned out a bit bigger than calculated, but should work fine.

Added the charging port and soldered the wires for it today, but forgot to take a picture. The battery charged up just fine with a 2A 24v liion ebike charger. Afterwards, I made the electronics enclosure by wrapping the battery enclosure in painters tape and putting it on an board, so it is slightly higher. This was in hope to get a nice fit when sliding the battery in later.

Trimmed the new enclosure much like the battery one and oh wonder, it fits! The battery enclosure will slide about 2 cm inside the electronics one and plug in the fixed EC5 in the process. I will be held by the fixed electronics enclosure, the metal clip preventing it from sliding out and the strap with plastic snap thing will keep it from falling down on the other end. At least I hope it will work out like that!


Let me know what you think!