It’s been quite warm in the Seattle area these past couple of days so since my shop is about 10 degrees cooler than the house I figured I’d go down there and work on one of the projects that’s been on my list, fixing the bushings on my Propel Endeavor.
The original bushings are these weird rivet looking things that are made from copper or brass, but after a time they get beat down and the board developed a distinct clunk on that corner.
A bit of time on the lathe with some Delrin (delrin is magic, change my mind!) I turned and installed new bushings on both sides of the rear outer suspension.
So of course a test ride was in order. So I headed out to a local wathershed which is almost unknown and has very eMTB friendly trails (and is similarly 10 degrees cooler).
The ride started out fine, the trails are suffering from mid summer rocks and roots but nothing unusual. About 2/3rds through the loop I went over a piece of wood and started down a hill when the board stopped responding to the throttle and started making a humming noise. I stepped off of it and it started to back up, then copious amounts of magic smoke.
So then I had a nice 1.4 mile hike and a very very smelly drive home.
My protocol in cases like this is to keep the board in a fireproof place for at least 3 weeks before bringing it indoors again, so I’ll keep it in the fire pit in the back yard with a tarp over it. Sort of an ignominious ending but better than burning down the house.
I’ll post pictures of the wreckage. Hopefully a new ESC (I have a makerX in stock) will bring it back to life, but I was really hoping that since this is a retail board it wouldn’t become yet another esk8 project. I already have plenty of those.
So you know what the first thing I noticed on this is? There’s no cover plate over the ESC board. All the aftermarket boards (save for the Flipsky maybe) have a cover over the top and a heat sink on the bottom. So no bits of metal could possibly short out a component of the board.
Which was just floating around in the battery box. So far as I know this spring has no place on this board - the only (small) springs I’m aware of are on the outside of the box near the bushings.
So theory 1 is that this spring shorted the wrong thing at the wrong time. Presumably it’s been bouncing around in there since I got the board (possibly since the board was manufactured) so I guess I’m lucky that it lasted as long as it did.
Propel! If you’re listening, put a cover over your PCB’s!!! Also, Propel, if you’re listening, send me a new Endeavor. Without the spring this time.
The last thing I noticed is that on that board absolutely no component went undestroyed. Like everything that could have burned burned.
On the upside the battery pack took minimal damage, and both battery wires de-soldered themselves from the PCB (which makes them a “fuse” based on the melting temperature of solder) so probably the pack is still good. I’m going to leave it in quarantine for 3 weeks then test it.
Also, I know where the spring came from. These boards have little twist covers over the charge port which is on the bottom of the board. The cover has a spring in it that causes it to lock in place when you close it after a charge.
So when the cover gets snapped off by a root or whatever I happen to hit the spring is left on the inside of the board unfettered from its tether and free to wreak all manner of havoc.
Here’s the hole where the spring used to be part of the assembly
Well, Propel responded typically - out of warranty not our problem. So I guess for me they are off my preferred vendor list.
It feels like yes, it’s out of warranty, yes it’s a 4 year old board (as they adroitly pointed out) but it’s my opinion that if something literally goes up in smoke in the middle of the ride it’s a slightly bigger issue than warranty.
But there you have.
I’ll see if I can get it back up and running with the MakerX. Assuming there’s no funny business with the wires it might be a plug and play affair.
The only thing I’m concerned about is that it has an aluminum base and a carbon fiber top so not RF friendly. The original board had an external stub antenna but I’ll have to put a Hoyt receiver in there which I don’t think has u.fl for external antenna.
I also want to add a loop key so that means cutting through the aluminum tub.
Maybe I can figure out a way to cut a void big enough so I can have a plastic panel that includes the loop port and space for the receiver.
Ok, so despite my rather packed schedule I’ve begun working on rebuilding this board.
First, to get the smell out I cleaned all the surfaces with soapy water, then rubbing alcohol. After a little Googling I decided on 2 more steps. First, baking soda and second a small fan pointed at the smelliest areas. My theory being that if odor is particulate I can speed up the degradation process by moving more air over it.
Next, I inspected all the wires and they seemed intact, so to get to the MakerX I had to swap motor sensor connectors. They didn’t color match, but I made the possibly wrong assumption that they position matched between the original board which was a Flipsky Dual FSESC 4.2. and the MakerX.
Then I found out that I have zero motor connectors in stock, so I ordered some of those, an anti-spark and a Bluetooth module which should arrive today.
I don’t know if the motor sensors are still electrically operational after the big flameout but I’m hoping they are. I guess I’ll know when I power the thing up.
Someone (probably me) should make a little handheld motor sensor tester. I actually made a very similar device for work a long time ago that I could pretty easily modify… It was called “The Tick” and it told me the number of ticks away from index the rotor was in. So it already understands halls. Might just be a matter of swapping the connector and rewriting the logic.
But of course that won’t happen if the motors work
I still haven’t solved the RF problem, but I’m wondering if the “P” in the middle of the board is plastic and if there’s CF underneath it. If so (and not) then I could position the Hoyt and BT receivers there.
Success! Took it out on a nice hilly gravelly route and it ran perfectly. I started at 60 battery amps and 36.5 motor amps, then upped the motor amps to 46.5 and the battery amps to 70. I think there’s still some headroom available because it seems like it isn’t as powerful as the original driver, but I need to check the numbers for how Propel configures their ESC’s.
(does anyone actually know what the Propel factory ESC settings are? My Google fu failed me on this one)
anyway here are the stats:
test miles: 6.5
fires: 0
magic smoke: None
bloody knees: 0
sudden inexplicable disconnects: 0
times flung off the front of the board: 0
times flung off the back of the board: 0
things I didn’t do that I should have:
put a fuse inline with the battery connection
account for RF loss from CF deck
Loop Key
telematics (battery level, distance, current speed, etc.)
test charging
Those are on the list as well as replacing all the copper bushings with Delrin.
I still get the occasional whiff of magic smoke smell when I’m driving too and from the sk8 destination but time should fix that. And keeping it in the carport.
But for now I’m really happy that I have a full suspension board back in the quiver.
We’ll see…
