After reading up intensively I’ve decided to pull the trigger and start my own build thread.
I’m aiming for a dual rear drive setup.
What I currently have planned:
Board: Loaded Dervish
Trucks: Randall R2 baseplates & bushings + Paris 195 hangers
Motor mounts: Torqueboards V1
Motors: dual RSPEC 6355 190kv
Motor management: dual VESC
I need to sort out batteries soon, but I’ll go with Lipos because I already own two balancing chargers.
More on that later.
First problem: the Paris hangers are not cylindrical, causing the motor mounts to diverge.
After asking for advice on the other forum, I decided to modify them.
I wish I had access to a lathe but I made do with what I have.
I put the hanger into a drill press and added a wheel at the bottom to stabilize the whole thing. Weird, even new hangers have bent axles.
I then carefully filed away ath the rotating hanger until my washer (you can see it on the wheel) went all the way over.
After some light polishing this is the end result:
I transplanted the Paris hangers to the Randall baseplates on my Dervish and I kept the conical Randall bushings, which I really like. No noticable difference in handling with the slightly wider hangers.
I left the baseplates on because I’m too lazy to remove them, I had already countersunk them, and they’ve acquired a very nice patina over the years:
With the modified hangers the motor mount flange is now perfectly perpendicular to the axle:
Contrary to some folks I’m really not interested in the aesthetics, as long as the board shreds. This is my trusty Dervish, I can say we’ve both been around the block a few times.
I’m waiting for motors, and then I’ll decide if I’ll keep them inboard or go outboard to the back. The dropthrough deck doesn’t allow that much clearance so I think out to the back will be my best bet.
Looking good…going to be a nice build
Nice build! What are you using for an enclosure?
I have no idea yet what I’ll be using.
I haven’t given that a lot of thought yet.
Winter is long enough to figure something out.
great idea with the drill press…
I used to have a Dervish and they are so damn awesome. One thing to watch out for is going to be board flex. They flex like crazy (being bamboo) so it’s something to keep in mind when attaching parts to the board. The board will flex and your enclosure will have to be able to as well. Screws might not like that! Straps may be the way to go for this one.
I agree on the board flex. They used to have two different levels of flex. Even the stiffer one i bottomed out sometimes when stepping hard on the edge of the board. I would worry putting anything under it for me. It is an awesome cruizin board though … still love my loaded bhangra better! =p
Ah yes, the flex. And its a dropthrough.
That is what I like about the Dervish.
If I keep my components close enough to the trucks, I think I might get away with it.
If worst come to worse… You can always mount the trucks on the bottom and even add risers.
Today was battery day.
Considering the fact that I want to use ‘fragile’ Lipo’s and the Dervish is quite flexy, I spent some time jumping up and down on the board in my garage this afternoon.
35mm thickness would be the absolute max and in that case I would need an enclosure capable of withstanding scraping the pavement when I max the board out, which I WILL do when carving, I’m not the lightest of riders. 25mm max would be ideal.
I think going with 12S makes the most sense as the current will be lower and the resistive heat losses will be considerably less.
With 12S, the 190kv motor, 90m wheels and a 15/36 reduction the calculated theoretical top speed would probably be too much for me but if I’m not mistaken the VESC will let me limit the motor RPM’s to a comfortable level. Am I right ?
So I went onto the Hobbyking battery selector and it turns out only 4 x 3S would allow me to keep the thickness under 25mm.
At least 5000mAh should get me far enough.
Theoretically a dual R-spec 6355-190 setup would be 4800W installed power. At 44,4V the corresponding max total current would be 108A but I’m guessing that would be peak so I think continuous discharge rate for the 5Ah Lipo’s should be in the 10 to 20C range, not higher. AND I can limit the battery current in the VESC anyway right ?
This query returns 5 options for the EU warehouse:
Multistar High Capacity 3S 5200mAh Multi-Rotor Lipo Pack
Cheap, light and compact. What’s not to like about these ?
Only 10C but if I read @okp’s Vanguard thread correctly I could get away with these.
The next three are very similarly priced, have 25C rating and have more or less the same dimensions.
ZIPPY Flightmax 5000mAh 3S1P 20C
Turnigy 5000mAh 3S 25C Lipo Pack
ZIPPY Flightmax 5000mAh 3S1P 25C
Finally there’s this one, which I don’t really see the advantage of using, its expensive but it can be charged ad 5C, which my chargers won’t do.
- Turnigy nano-tech 5000mah 3S 25~50C Lipo Pack
To conclude, I think I’ll risk ordering 4 of those cheap Multistars, unless any experienced users here on the forum have other recommendations ?
I have used the Zippy flight max on all of my builds for over a year now, I have put over 500km on them and they are still going stong.
the minimum I have used is 20C and there have been no issues so far.
I think as long as you care for them properly they will be fine.
lipos are great batteries just not idiot proof.
If I ever buy lipos again ill pay the premium and get the better ones, the zippy flightmax have let me down before.
That’s right @trbt555 . RPM limits on VESC work perfectly. I’m using this feature now as I get used to my build and don’t need to hit its top speed. This way I can test things without any worry. Remote signal drops? Enclosure falls off? Motor wire unattaches? NBD cuz I’m only going 12 MPH!
I made some progress today.
This week I happened upon these lunchboxes which turned out to be perfect for my build. They’re flat (33mm), they have rubber seals and reliable latches and they’re quite strong.
I temporarily mounted them on rubber bushings using M5 bolts through the deck. I drilled all holes slightly bigger to have some play to account for the board flex.
I pushed a few times around the block and took a few descents carving, the mounting seems te be rock-solid.
I also made a cutout for the anti-spark loop key:
I’m currently waiting for my fuse to arrive, after which I’ll be able to mount & wire the batteries into the box.
I did go for the Multistar batteries after all, we’ll have to see how they hold up once I get the motors & VESCS.
those boxes are perfect! great find… i remember my countless hours of searching for the perfect pre-made boxes… walking around shopping malls looking like a box zombie… i think you nailed it with these!
those are some pretty nice boxes there. how are you going to wire it? battery in one box and VESC in the other?
also are you going to remove each battery for charging?
Yes, batteries up front, VESCs towards the drive side.
Because the lids are so easily removed, I’m keeping the batteries in the box, fixed with velcro.
I already own two chargers so I’ll parallel charge 2 x 2 packs overnight.
Today I put the power meter in the drive-side box.
I like easy access so I didn’t mount it to the lid but mounted it to the bottom of the box on a riser to bring the display up to the right level.
I wasn’t happy with the look of the display in the cutout so I transplanted the original bezel:
This week I’ll be receivng my fuse and then I’ll mount the boxes and wire them up.
Then comes the countdown to the November batch of Vesc…
@trbt555 I ordered one of these lunch boxes as a replacement for my plastic screw-organizer enclosure that recently failed, thx for the inspiration! I made a flat spot on the bottom of my deck with epoxy. It also eliminates flex in that area (which you don’t want, but I prefer). Are you going to line the interior of the box with anything so that it doesn’t facilitate shorts? You mentioned some rubber bushings around the bolts but it also looks like there is a layer of black rubber\silicone between the deck and the boxes; is that a full sheet of rubber?