Throttle ?: Using a pot instead of hall/magnet throttle.

[goinmobile]

I'm sorting/testing various brushed controllers & questionable throttles. Either a faulty controller or throttle can damage each other, but I do not know the technical reasons why. That fact is not a question as I will not repair controllers, but will repair throttles with replacment Honeywell halls. There is no store to run to for replacements, mail order parts are in transit, international border timing unknown's too.

The jc-116 group of 5 controllers needs a resistor of 2200 ohms for a pot to work properly, according to the importer in Tenn. This isn't available, so I'm asking for help on a substitute.

Can I damage the controllers by using the pot without the 2200 ohm resistor connected? I had this pot taped to my bike for a spare for when ebike haters tamper with throttles, pull out the wires & stick back into the housing hole, This happens with brake cut out too. So this pot runs the bike very slow, but gets me home.

Does the resister go in series with the 5v power (R & B), or the signal wire (green)? Maybe its parallel?

I have scrap electronics, Wellar adjustable solder tools & my meter detects to 0.001 ohms. I can work with wire soldered resistors, not tiny flush mount ones. Issue here is eyes & hand coordination. Might be smarter to buy Magura in the future.

The only pot I can use is out of a broken throttle, 5v input gives a normal gradual increase from 0.0 v to 5.1v.

Can I series resistors to get 2200 ohms? If I meter say 3 resistors that add up to 2200, will that duplicate results of the desired 2200 resistor?

Any other part in scrap boards that will work?

[amberwolf]

You can always series resistors to get the right value. In series they just add.

In parallel they combine in a different way, though I can't figure out a good way to write the formula in text so I'll just link this calculator:
http://www.sengpielaudio.com/calculator-paralresist.htm

I don't know if it would hurt anything to leave the 2200ohm resistor out--without having a full controller schematic it's hard to say. My guess is it wouldn't *damage* anything, but it may not operate the way you expect it to, especially at the extreme ends of the pot's range.

Some controllers care about what ohms value the pot you use is, like some of hte 4QD brand ones; if it's too low or too high, it triggers it's "throttle fault" circuits. Most don't care as long as the voltage input range out of the pot is correct.

[goinmobile]

Thanks Amberwolf for helping. I can get close to the 2200 ohms by series then.

The bike got me home using this exact pot but slowly if I recall correctly. The importer says it will not get to speed without the resistor & he was guessing the exact value as he had no access to his computer Friday night. I can get this info tomorrow night, Monday, by phone. I think this is day 5 of no go lessons.

I still need to use this pot when the new controllers arrive, as I did buy throttles. I have 15 or so here that can be repaired, minus the glued in ones. There are a variety, having differing shaped sensors. The correct Honeywell's can be had a week tomorrow from a local distributor. Maybe USA from Digikey in 10 piece lots.

I just retested all my controllers. Connections are : battery last; 3.3V feed on the throttle ground(black) & + on the green signal wire; lock (jumper loop)& still off for connecting power.

Verify voltage values, then connect meter to the motor leads, 0.0v & a correct reading. Now the lock loop on, reading is 39.4 on the motor leads. This is incorrect, as the 3.3v into the throttle controller connection should result in about 65% or 24v (3.3 over 5.0v).

Result is on 5 jc-116's, all are no good. If I recall correctly there is no amps backing the 39volts, wheel is very slow when suspended. If it is top speed instead then it will be hard on the internal freewheel & spokes.

The 2 pedal first controllers mention in my other piss-up thread are no good either, one has 39.4v on above test, other does nothing. Tried PF sensor installed & moving the magnet, N/S positions, blue leads connector on & off, all the possible combinations.

So I've destroyed some good controllers, 2 jc-116, 1 PF, 1 24v and unknown number of throttles. 116's were new, rest used but tested before scrapping the bikes. Positive here is I still have all my fuses I started with!

All over a broken throttle housing, I still have it, was glued so it has parts of housing. This could work by taping to the bar just so & the magnet/grip just so. Plus a method that prevents them parting away, as its the mag that stops runaway voltage.

A light just clicked, I have a throttle housing that has a large enough gap to place this sensor, it has a magnet on each end of the gap. I have a working 12V 200w 24amp controller from a kiddy bike to test on.

My mobility options are very limited now. Direct voltage options? I'm thinking to rewire a battery pack into 3 12v, use 3 relays and 3 low voltage switches for handlebar mounting/use. I can use a 4th relay thru the brake levers to cut out the 3 power relays. The 3 relay group is under 2 watts each, so 4-5 watts going thru the brake switches. Will the brake parts take it? For a week?

I have one switch that can run 2 relays, mounted on a Magura hall type throttle. Disassembled it & found an impressive 2 position bar style contact, lots of contact surface.

Can you imagine my costs if I had BLDC parts?

Pedaling is not an option for transport should you wonder on that. Whatever you do ,don't "say you're lazy". Big grin on that, but thin ice.

[d8veh]

Iuse 10k potentiometers on all my bikes as throttles without additional resistors and have had no problems. Maybe other controllers are different. The 2200 ohms is just approximate: you don't have to match it exactly. Anything within +/- 10% will be OK - probably +/- 20% too.

[goinmobile]

Thats very helpful d8veh. I assume my pot is a potentiometer. How to measure? If mine is less than 10k then adding resistors can increase this value, until it works? Different controllers will have differing results then.

What are you using for throttle housing? Got spring return?

I but cheap mostly over theft & vandals. BLDC & decent LiFePo4 is far too expensive for parking lots.

The cage drivers sure hate ebikes here & damage parked bikes. Its that bad, demanding ebikes move to sidewalks. We have provincial laws here stating "if the curb lane is too narrow to share SAFELY, it is LEGAL to take the whole lane". Online Ref: "Cycling Skills, Ontario's guide to safe cycling". The cagers hate that & still try to force you over. Triggers road rage too as they do not know the cycling rules.

[d8veh]

Potentiometers have the value stamped on them somewhere. Also, look out for "Log" or "Lin". You want "Lin", although "Log" will still work. I don't use a return spring because I use them for cruise control with a switch that switches over from normal throttle. I house them in a little 1" cube plastic box zip-tied to the handlebars.

All the potentiometer does is split the 5v supply in proportion to the amount of turn so that you get 5v one end and 0v at the other and 2.5v in the middle for a linear ("Lin") one. I guess the guy who told you to use a 2200 ohm resistor doesn't want the full 5v dumped into the throttle signal input without any resistance, so if you put a 2k resistor on the output, the voltage would be split in the ratio 10k to(10K+2k) at full throttle, which would give a voltage of about 4.2v, which is still about enough to give full throttle because the controller doesn't use the whole band anyway, and the 2k resistor would stop excessive current to the throttle input; or maybe he was thinking about using the whole range of the pot to get better resolution for the throttle. Who knows? Anyway, it won't do any harm to use the 2200 (or thereabouts) resistor.

[goinmobile]

That clears up my issues, thank both of you, very helpful. So much good on this forum.

I measured this pot, 10k to 0.004k. My controller order is here tomorrow, cleared customs quick. Now its Monday so I can get resistors & a few 10k pots instead of salvaging used parts. The downtime doesn't hurt, just the frustration on testing & distractions in another related thread.

Cutting wires on ALL the tested controllers, even throttles, as memory does fail me. I blunder with this & hand coordination every day, some days every hour. Don't distract me while I hold liquid solder! Approach with safety glasses. Surviving is laughing them off, make reminder notes that are not in the right location at the right time.

I don't eat ice cream cones as that's real funny, feed the nose instead of the mouth occasionally , cold tongue mumbling "no I don't want a spoon" to concerned help, their eyebrows furrow deeper with concern over the speech impairment, then I crack up. Most always ends in understanding unless the concerned bolts. Day 6 or 7 downtime? haha. Thanks all.

[SamTexas]

d8veh, I never knew that a potentiometer can be used instead of a throttle. I'm going to try it myself. Thanks.

Cutting wires on ALL the tested controllers, even throttles, as memory does fail me. I blunder with this & hand coordination every day, some days every hour. Don't distract me while I hold liquid solder! Approach with safety glasses. Surviving is laughing them off, make reminder notes that are not in the right location at the right time.

I don't eat ice cream cones as that's real funny, feed the nose instead of the mouth occasionally , cold tongue mumbling "no I don't want a spoon" to concerned help, their eyebrows furrow deeper with concern over the speech impairment, then I crack up. Most always ends in understanding unless the concerned bolts. Day 6 or 7 downtime? haha.

Being able to laugh at one's own shortcomings is one of the best thing one can do to and for oneself. Cheers!

[Kin]

Pots, on the downside, are more liable to have problems with weather and age/oxidation related change in resistance.

[d8veh]

d8veh, I never knew that a potentiometer can be used instead of a throttle. I'm going to try it myself. Thanks.

Go for it. Once you get used to switching it on and off, you might find it better than a normal throttle depending on your riding style. Even though I have a normal throttle as well, I can't remember the last time I used it. If you can get one of those little 1" cube project boxes, you can fit a toggle switch on the side rigt where your thumb goes.
Edit:
I'd advise you not to do it unless you've got brake cut-outs other than for testing.

[SamTexas]

Once you get used to switching it on and off, you might find it better than a normal throttle depending on your riding style. Even though I have a normal throttle as well,...

Sounds like you have both of them active simultaneously? Are you paralleling the 3 wires before connecting them to the controller?

... If you can get one of those little 1" cube project boxes, you can fit a toggle switch on the side rigt where your thumb goes.

What 1" cube project boxes? What do they look like and where can I get them?

Edit:
I'd advise you not to do it unless you've got brake cut-outs other than for testing.

No worries. Ebrake is not an option for me, it's a requirement.

[goinmobile]

d8veh, Are you using a wheel type mounted inside the cube? I was happy seeing short sliders on Digikey of 20 & 35mm until that thought struck.

The local supply wanted $12.95 for an in-stock 10k slide 2w. Digikey's are rated at far less that 1w, doesn't mean I was on the right page. Does that rating matter?

I'm going to upgrade my brake cutouts too. I have accumulated some pairs of older metal chassis thumb shifters with finger levers levers, Shimano 21 spd. Install external switches with visible wire contacts, always soldered. I have Wajax now, lever pins are soft aluminum get sloppy/shear. Easy upgrade, bolt, nut & red lock tight. Solder iron will heat to 500F at service. I recall a build thread with photos for swt. moding. I'll buy reliable quality for these switches. Even got the road type cables for this upgrade, new from MEC's sale last year.

Kim warned of resistance change, whats the service life for our bike applications? Another thought is rain conduction, can it result in a dead short?

[d8veh]

Have a look here: Towards the bottom of the page there's a photo and schematic of how I do it. I have the KU series of controllers from BMSBattery. I'm pretty sure that it would be OK for other controllers, but you might want to try a 1K or 2K resistor on the middle pin of the pot first to make sure no damage to yours.
viewtopic.php?f=3&t=40046&p=585701&hilit=+cruise#p584873
I got the box from Maplin Electronics code FD96E, but you should be able to get them from any electronics supplier. They're called "potting boxes"
http://www.maplin.co.uk/potting-boxes-1664
Potentiometer
http://www.maplin.co.uk/standard-potentiometers-2205
Any type of linear pot should be OK because there's no significant current. A slider type too should work if that's what you want. I filled the back of my little box with silicone sealant, but didn't bother sealing the outside of the switch or pot, which has been OK in the rain so far, but I wouldn't want to leave it out in the rain for a long time, but thereagain a normal throttle isn't waterproof either.

[d8veh]

Pots, on the downside, are more liable to have problems with weather and age/oxidation related change in resistance.

True, so be mindful of this, but these problems don't normally cause sudden failure. I think the main thing to think about is water getting in. I've been using mine (real cheap one) for over a year and no problems so far - and they only cost $2 to replace if anything does go wrong. I must say that mine hsve never had a serious soaking though - just showers.

[SamTexas]

Thanks d8veh.

[goinmobile]

The importer replied that pots will damage the jc-116 controller & his entire product line with incorrect current. Should this fact be edited into the first post as few read entire threads?

So the resistor limits the voltage, how do I lower the current? I have asked for the current values, usually a day to get response, may be tired of my questions too. Also asked for specs to select the correct Honeywell halls.

He told me to use his throttles before, but I had new in-hand, at half the cost of importing. Had I known the technical then...

Is anyone aware of this info in another thread?

[SamTexas]

The importer replied that pots will damage the jc-116 controller & his entire product line with incorrect current.
...
He told me to use his throttles before,

Sounds like a typical standard answer to me. If I were you, I would ask "What is the correct current?". Most likely there won't be an answer.

Of course he wants you to use his throttles. How else can he make money?

[goinmobile]

SamT, I thought of that too, thanks for pointing it out. I have total confidence with this business. We don't know the depth of his business, if it's proprietor info, them likely for good reasons. I expect an answer from him, I believe he is busy with vendors during the day, so this evening or tomorrow. He imports from China, mass market products, I don't see a need for secrets when he stated he has the tech on file.

Meantime I need to get mobile & asked that here. I have new controllers, jc-116. The old worked nearly a year. The throttle worked the same period, the case broke, not the sensor as I got home by taping the mismatched housing .

I can trust this sensor. It was glued into the housing, so it will not fit into another. I cut most of the case bits away. I have a housing with a large gap that I can fool with, bench test first, as a loose magnet or sensor hooked to a live wheel can be trouble.

The more I look, the more questions need answers. My earlier post should have asked if hall current can be measured without damage to it or the controller. Get that value from this hall to test against the unknown group later. This needs leaving the wire attached instead of cutting off can't get funnier than that. Phone my doctor & demand a memory transplant & I neeeeed it today.

Anyone test Amberwolf's resistor conversion link? Very cool on the parallel matching. Way easier than amateur pen & paper. Tested parallel, 100 ohms + 100, = 50. Simple. Then 100 & 200, = 0.67. I would have concluded a number ending in a 25. Like AW said, the math formula is complicated, thanks for that eye opener AW.

Useful for amateurs like me.

[goinmobile]

Pot didn't survive, 2 of three legs broke, out of patience. Learned about how not to salvage resistors too.

I still want to use pots, no fatigue from the spring. New & spares.

I have rejected throttles having twist readings of 0.8v to 4.1v then decrease to 2.5v. I realized the bike ran fine for a year loosing top end on full twist & a sweet spot early in the twist. Live test soon.

Tiring.




I

[amberwolf]

You cna also get pot throttles out of old powerchair / electric wheelchair equipment. A "paddle" style pot / lever is used on some Pride three-wheel powerchairs--you could use the pot with or without the paddle. If you know anyone or anyplace near you that does powerchair repair, they probably get used good parts off scrapped chairs all the time, and might have one for cheap (or even free if you make the right friends).

[goinmobile]

The bike runs, new controller & an old throttle. I can get to radio shack, get some resistors & a 10k pot. New. This throttle has the sweet spot about half twist & a steeper power drop that the broken one, as metering indicated. Can adding resistance get a full throttle swing?

A scooter pot could work, expensive new, salvage may be hard as scrappers get it, rots in the rain on the outskirts somewhere. Offer money, them it must be gold, hoard them.

Playing with the scrap boards yesterday went beyond my skills & tools. I think a needle tip is needed, breaking wire mostly. Then the oxidized surface, getting stick, acid spreading on the board & elsewhere. Parts are too small.

"I can't do that" was never acceptable all my life. Nooooo....

Big parts, long leads, how about tubes? Wire leads from the sockets, screw mounted to metal? Joking, I'm done with salvage on scrap boards.

Best I do radio shack & make a backup pot throttle, order parts from digikey, wheel & slide pots for perfect thumb motion. Glue well for vibration then mount with silicone to get the desired position & angle. Reasoning here is getting rid of spring fatigue. Silicone over anything in the way, forget about parts servicing, change handlebars instead. No more issues with hidden bolts too !
Advanced concepts, spare bar sticking out of the saddlebags. haha.

Maybe buy a matched throttle, get the values of the importers claimed need of current values before ordering halls? Is current a hall sensor spec? How to measure this? Can this be proven without the importers specs?