Did I just fry my throttle?

ClintBX

1 kW
Joined
Mar 6, 2014
Messages
419
Hi ESFMs,

I recently had to replace my twist throttle after an incident on an escalator destroying my last throttle.

The new throttle is a twist throttle with 3 speed wires and a voltage display wire.

Ever since I've had it, I've noticed that it would display less voltage than normal. 54.1v instead of 54.6v on a full charge. And I know it's the throttle and not the battery packs because my multimeter is showing it's full capacity.

I made the mistake of playing with the wires. I tried to put one of the blue speed wires into my controller's voltage display wire. When I connected the pack to the controller, there was a loud spark and some smoke coming from both the battery connector and the display connector.

Now the throttle doesn't respond and the display is showing 43v instead of 54v. I know the controller is still fine because I tested my emergency thumb throttle and it worked.

I didn't realize that swapping the display with one of the three speeds was going to kill it. I didn't touch the essential black, red and green wires.Thoughts?
 
ClintBX said:
Ever since I've had it, I've noticed that it would display less voltage than normal. 54.1v instead of 54.6v on a full charge. And I know it's the throttle and not the battery packs because my multimeter is showing it's full capacity.

I didn't realize that swapping the display with one of the three speeds was going to kill it. I didn't touch the essential black, red and green wires.Thoughts?
Likely. swapping wires randomly rarely ends well.
You'd be lucky to find one of those combo throttle/voltmeter displays that come closer than a half volt of the actual voltage. Just poorly calibrated, so nothing "wrong" with it, but tolerences. I've had a couple.
 
Surely you meant that the throttle was just cheap as Borscht soup, for not reading the voltage accurately because of B.O.M. and price point reaching. It could also be a loss-leader where they dont make what they ought to make off an item, taking a loss of that maxed out potential price point for ultimate sales. Why anyone expects the world from cheapness is beyond me, but I know you know, I'm just saying. It's not like that Dollarama can opener is going to last you very long, lucky if it reaches 2+ yrs in most cases, for everyone I ever owned because I wanted a cheap can opener. But you see that can opener cost me $2.50 for that bad line of thinking, where as a Walmart can opener would last 4 maybe 5 yrs and cost $9.99, but a good quality can opener could cost as much as $20-$25 if its made by Kitchen Aid. That item has lasted decades man, friggin decades. I miss those times when you could easily buy a quality item and it will last. Now, you have to search far and wide, skip Walmart and dont even look in the direction of any dollar store. And funny enough, Kitchen Aid can openers are probably made in the country that shall be un-named C.

You get what you pay for, when buying cheap stuff.
The game works the other, but in reverse because just because something is expensive doesnt mean it will last.

We all know this, but we seem to shove it under the rug. Its easier that way, easier on the pocket book too in these tough inflationary times.

E-HP said:
Just poorly calibrated, so nothing "wrong" with it, but tolerences. I've had a couple.
 
calab said:
You get what you pay for, when buying cheap stuff.
The game works the other, but in reverse because just because something is expensive doesnt mean it will last.

For monitoring battery voltage, you don't need anything expensive. Not much technology going into a voltmeter, so they are cheap, and just need calibration. I got a couple of ones like this to monitor my lipos. I adjusted it so it's spot on with my multimeter. $7 and more accurate than my $130 Cycle Analyst, that's off by a tenth or so.

I bought this type because it's a two wire, when most require a lower voltage input to drive the display, this one can just take battery voltage up to 120V without the lower volatage inputs:
https://www.amazon.com/gp/product/B0969S42QP/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
 
ClintBX said:
I made the mistake of playing with the wires. I tried to put one of the blue speed wires into my controller's voltage display wire. When I connected the pack to the controller, there was a loud spark and some smoke coming from both the battery connector and the display connector.
The voltage display wire has full battery voltage on it.

Connecting battery voltage to ANYTHING that is not designed and intended to be used with that voltage is not recommended; it can destroy things not designed for it and even cause fires from arcing and overheating. (it might not, but it certainly happens)


THe three-speed wires are normally a ground wire in the center, and two other wires that go to your controller's connector for this function if it has one. If you had the switch on either high or low position when connecting one of the speed wires to battery positive, and the center wire was wired to ground (either internally at the factory or by you when hooking it up), then you directly shorted the battery to ground.

The current flow will be enormous, and if the internal ground is the same one used by the throttle (likely) it probably blew the trace or wire open, so the throttle wouldn't work because it doesn't have a ground anymore. (though this usually results in full-throttle output by the controller, some of them have safety features that prevent that).

The arcing that can happen during an event like this makes a lot of high energy RF, which can destroy electronics on the same circuit, so this could have blown the hall sensor itself, as well. (not common, but it can happen).
 
I dont know much about that, but I have opened up a few dmm's, I buy the cheap ones when they are on sale. So the final price could range between $10-20 depending on the features, so regular price would have been $50+, do the same with digital calipers which go on sale for $5 instead of $25.
About the best I can read is xx.x volts, so 20.2v for example is all I can read. I may have to splurge on that Aussie guy EEV blog dmm thats branded.
Yes, I've played around with the rc lipo volt readers, they always seemed to be off when checked by the cheap dmm. Maybe splurge hard and buy a used Fluke. Should switch to mechanical connectors, getting low on solder and buying the small rolls adds up fast, $4 (1g) vs $20 (10g)
Even the 50 or 80w rc balance charger read the voltage wrong, but you'd always compensate, saying arghhh good enough.
 
Turns out I did destroy my controller. The throttle still works fine. My spare throttle gave me a false positive when I tested it briefly before leaving the house for work.

When I came back home thinking I just had to prep and install the new throttle I had (lying around just in casies), that's when I discovered that it was not a throttle issue, as the new throttle was failing to respond and it too was displaying only 44.7v(instead of a full 54.6v). It's as if the controller is not receiving the packs' full charge.

I had a spare controller lying around, so I ended up swapping that in.

I opened up the controller expecting to see a singed component but it actually looks quite good inside. How can I identify the damage? How do I troubleshoot it?
 
amberwolf said:
THe three-speed wires are normally a ground wire in the center, and two other wires that go to your controller's connector for this function if it has one. If you had the switch on either high or low position when connecting one of the speed wires to battery positive, and the center wire was wired to ground (either internally at the factory or by you when hooking it up), then you directly shorted the battery to ground.

This might be a clue to what happened.

In order to get my voltage display to work on these kinds of throttles, I have to splice the yellow display wire info the red+ line. On this controller, I chose to use the ignition wire pairing. The red/purple pair. I replaced the molex connector with a bullet connector so I could bridge my ignition circuit and use for my voltage indicator simultaneously. Works well. Anyway, I think the blue wire on the throttle that I thoughtlessly tried to plug into my "indicator/ignition" port may have been the ground wire for the throttle. Good lesson
 
If battery voltage was passed thru the throttle signal via the throttle from it's ground, then the MCU (and the throttle hall sensor) is probably fried, because the input for the throttle on the MCU is only able to handle 5v or less inputs.

If the controller no longer outputs 5v, then it may also have fried the low voltage power supply in the controller.

But a fried MCU is unrepairable, anyway, because even if you get a new MCU, you can't get the firmware to flash it with. :(
 
amberwolf said:
But a fried MCU is unrepairable, anyway, because even if you get a new MCU, you can't get the firmware to flash it with. :(

I don't think I have a soldering tip fine enough or hands steady enough to solder an MCU chip in. Maybe when I was 20 something. If you do it, take videos.
 
Generally I'd expect people would want to use hot-air reflow machines for this kind of work (though some people are good enough with the right tools to do it by hand).

But in this case, unless there is another identical controller to pull an MCU from, I don't know where else a new MCU with the firmware on it could be had, and so if the MCU in this controller *is* damaged, it's just a brick now.

(and if you did have an identical controller, presuming it works, there's no reason to break it to fix this one; if it's broken in some other way that doesn't involve the MCU, it might be, but personally I'd rather use this one's parts to fix the one with a working MCU, as the solder/desolder operations should be easier. ;) )
 
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