eBike Emergency Triage - aka - Field Repairs

mwkeefer

1 MW
Joined
Jun 14, 2009
Messages
2,263
Location
Malvern, PA USA
[Hall Throttle Failure]

Hello all,

I'm sure this exists elsewhere (doesn't everything now) but last night I noticed my trailer hitch on a Dahon Jack (FWD geared hub 18S) was causing the rear wheel to move in it's mount (it's the receiver type hitch which wedges between the QR skewer for the rear wheel) thus royally screwing up my rear V brakes.

Needless to say - I did what any of us may, flipped the bike upside down and adjusted the tension on the rear skewer, reseated the axle and flipped it right side up.

Came out of the store and ... OH NO now my bike won't work!

As many would (who have had the experience)... I started checking wires, flipped the power off on the controller (I have a switch installed) and disconnected the pack... when reconnecting the pack I could see/hear the mildest of spark (caps are precharged so spark is minimal) so power was coming in... checked handlebar bag (installed on a front rack) battery pack for disconnection or somthing... all was good (darn near 9AH remaining)...

Next I pulled and reconnected the throttle - no good. Begin process again starting this time with sniffing the controller - whew no stink of burnt anything (worried somthing could have fallen loose when flipped upside down - the one test I never though of trying before hitting the road on the new build)!

The following time I connected the throttle (this was by accident) I must have connected it so only the VCC 5v and Return wires were connected to the throttle and the front wheel began to hum and nearly ripped the bike from my hands. Hmmm.

Powered down the controller and opened the throttle guard (screw panel) to find one of the hall sensor wires had come undone - directly at the base of the sensor. Normally breaking down outside a radioshack is a good thing - sadly they dont' even know what a hall sensor is (tried to send me to the pharmacy for throat lozenges) but not with this issue... I thought quickly of doing some form of 5K pot just to adjust return voltage, then it dawned on me ... I ripped the wiring off the hall which was damaged anyway... seperated and stripped (yep with my teeth) the RED and GREEN (your results may vary but it will almost always be the RED and the non-black line for return) and after remembering to flip the controller back on and lift the front wheel, touching them together (the Green and Red) made the wheel spin up to full speed.

Now being close to RS came in handy, I could have just taped down the red wire to my handlegrip and physically held the green to it - would have even been sort of a dead mans switch but not much for control or stopping - I ran in and grabbed some momentary switches, quickly tape wrapped a switch to my bars between my thumb throttle and my hand grip and wired it up to the RED and GREEN wires.

Started off pedaling into 2nd then push the button and whalla... pulse and go with NO other option but it got me home!

Normally I would have taken it as a challenge, grabbed some bits and parts from Radio Shack and created my own POT based throttle to take the 5v input and return appprox 0v to 4.7 (wouldn't be fully possible but maybe 4.4v if done right) but as luck would have it my ex was having her car repaired and called me just as I was noticing the issue (about 4:30pm yesterday) asking if I could retrieve both kids from daycare (by 5:30pm) so elegance was not an option (neither was pedaling 7mi back home in under 40min, then fetching the kids 20min)!

I've got some pics I'll post later when I can re-rez them, I have a few other "gotcha" situations I've had to "rig" some in the field hack for and I will post those too... I'm sure others out here have similar experiences we can all learn some basic Emergency eBike Triage from?

Hope it helps!
-Mike
 
mwkeefer said:
Now being close to RS came in handy... I ran in and grabbed some momentary switches

How many times did they try and get you to buy a cell phone with that? Did you get the extended warranty? How many times did they try and put you on their mailing list? :x

That place is just way too annoying for me... I haven't set foot in one after the counter dork accused me of being a terrorist since I would not give them my name, address, etc after buying a few parts... well actually I didn't buy them... left them on the counter to be restocked. If they had an emergency exit slide, I'd have been on my way with a couple 'o beers in hand.
 
My radioshacks know better - they provide all their recyclables to me and call my company when they have questions with no answers.

Really I collect (free of charge) 2-400 lbs of sla and 100 lbs of nihm and liion a month from 6 stores within 15 miles. I desulfate what I can and donate them for wheelchairs and recycle the rest.

They also send me all their computer conulting work :)

a few even ride Ebikes by mike :)

- Mike
 
Nice save. My last failure was high on a hill, and the fried controller wouldn't let me coast down even with pedal help due to full force plug braking. I don't ride with any tools anymore, and my connections are bolt together with everything under a motorcycle seat that requires a small crescent or pliers and a phillips to get off and access anything. By some miracle I had forgotten a pair of nippers in my backpack and was able to snip through the wiring harness from the motor (at least in a fairly convenient location for later repair). Otherwise I might still be walking/pushing the bike down that mountain a week later. :oops: That's exactly what I get for being too cocky about how long I've gone without being stranded. F'ing current limiting with partial throttle up that very same hill is the only other time it's happened 19 months, so my cockiness was warranted, just not regarding that hill. :mrgreen: Maybe tomorrow I'll take off on a 50 mile ride with no tools at all just as a big F U to the breakdown gremlins. :twisted:

John
 
mwkeefer said:
My radioshacks know better

I wish mine did... In a previous life, a company that I founded sold MANY millions of dollars of computer boards to Radio Shack. Their engineering and quality people were first-rate++ and a real pleasure to work with. Their buyers were ruthless bastards and drove a hard bargain. Our salesmen were ruthless bastards and drove a hard bargain. A good (and profitable) time was had by all. Sometime afterwards the company seems to have lost its soul... probably stabbed in the back and thrown in a bog by clueless suits... such is life in the fast lane of consumer electronics. And if I wanted a freakin' cell phone, I would have asked for one.
 
I hate rat shack. I still find myself going in from time to time even though I know my personal electronics stock vastly exceeds what they now carry in terms of parts. I go inside, the sales clerk says "can I help you find something?", I say "do you carry flux capacitors?", they go to the catalog to look it up, I wander over to the single drawer that now houses their complete electronic parts inventory, shake my head in disgust, and leave.
 
KTP said:
I wander over to the single drawer that now houses their complete electronic parts inventory, shake my head in disgust, and leave.

A long way from the days when there was a 50 foot wall covered floor to ceiling with rows upon rows of bags of all sorts of nifty electro crap. And not a cell phone in sight. And free batteries. Dem's was 'da good ole days. Electrons came in glowing glass tubes. Dynamotors anyone? Can you say Poly Paks, Lafayette, Applebys, Meshna, Fair Radio (OK, actually still alive), and a few dozen other infamous places of yore?
 
I think there is a post with pics in my early Electricle blog, but once on a friction drive test the bike fell over and broke my scootngo hall throttle, so I repalced it with a pot out of a CRT computer monitor, and cleverly put it in the end of the handlebar so taht it's knob would be rotated by the mostly-working ex-hall-throttle's twist grip plastic. On a future test ride of other things, it fell over and broke that cleverly placed pot (shoved the shaft thru the back of the pot's PCB). :roll:

dinking with it allowed me to go a bit further, where I found a bigscreen CRT TV smashed at the end of an alleyway, main circuit board exposed. I found that one edge had a bunch of pots similar to waht I had used before, and broke away bits of PCB until I got some free. Fortunately the value must've been close enough to use because when I twisted the wires onto the pins and shoved it in the end of the bars, it worked well enough to get me home. :) (since then I've used a lot of parts off that TV board for other things, too).
 
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