Does anyone know which servo testers us a 5k potentiometer? I'm building a drive for my girlfriend's bike and have a bunch of ev warrior throttles (they use a 5k pot). I'd rather not make another custom throttle for her (her bike doesn't need to be than fancy, lol) so my search is on. The last cheap hobbycity tester I purchased used a 20k pot.
Servo testers that use a 5k pot
- Thread starter EVTodd
- Start date
recumpence
1 GW
Todd,
The Astro Flight servo tester uses a 10K pot. However, you can wire a 5K pot to it and it runs fine. Changing the POT value merely drives the circuitry a bit harder, but it still runs fine.
I hope that helps.
Matt
The Astro Flight servo tester uses a 10K pot. However, you can wire a 5K pot to it and it runs fine. Changing the POT value merely drives the circuitry a bit harder, but it still runs fine.
I hope that helps.
Matt
Hmmm, I tried using the 5k pot throttle on the cheap servo tester I mentioned and it wouldn't ramp up all the way. I assumed you had to use a pot that was rated at or higher to get full throttle. On the throttle I made myself I'm using a 50k pot on the tester that originally had a 20k.
I'm confused! :|
I'm confused! :|
recumpence
1 GW
The servo tester looks for the difference between the high leg and the low leg of the POT in relation to the center leg. So, the impedence really means very little. There may have been something else going on with your other tester.
At any rate, I have made many throttles with the Astro tester and a 5K pot and it always works fine.
Matt
At any rate, I have made many throttles with the Astro tester and a 5K pot and it always works fine.
Matt
I'm putting my girlfriend's bike together and I ran into the same problem with her throttle that I had with mine. This time the servo tester I got has a 10k pot and my throttle has a 5k. When wired to the servo tester the 5k won't let me fully accelerate.
I thought about swapping the pot in the throttle out for a 10k but it's one that I can't find locally and really don't feel like ordering it if I don't have to.
Matt says any pot should work fine but I'm just not finding that. Am I doing something wrong? I have the throttle pot wired exactly the same as the one the servo tester came with. Checked it with a meter and all that good stuff. It ramps the speed up but only halfway.
I remember reading a thread where someone used a hall throttle on a servo tester. Has anyone done that? If so, how? I have one sitting around here somewhere.
I thought about swapping the pot in the throttle out for a 10k but it's one that I can't find locally and really don't feel like ordering it if I don't have to.
Matt says any pot should work fine but I'm just not finding that. Am I doing something wrong? I have the throttle pot wired exactly the same as the one the servo tester came with. Checked it with a meter and all that good stuff. It ramps the speed up but only halfway.
I remember reading a thread where someone used a hall throttle on a servo tester. Has anyone done that? If so, how? I have one sitting around here somewhere.
olaf-lampe
10 kW
Maybe your servotester has some inline resitors before and/or after the potmeter? These values have to be reduced in the same ratio as the original poti vs the 5k poti ( eg 20k/5k=1/4)
-Olaf
-Olaf
olaf-lampe said:
I don't think it does but I'll take a look.
I wish i could just find a servo tester that I knew for sure used a 5k pot. Maybe I should just make one. Anyone have a really easy schematic of a servo tester I can make with parts from radio shack?
GGoodrum
1 MW
First of all, you did take the 20K pot out, or completely disconnected it, didn't you?
Instead of re-inventing the wheel, why not do what Matt said, and get yourself an AstoFlight servo tester? If you have any RC hobby shops in your area, you can probably find one, or you can order one off their website.
-- Gary
Instead of re-inventing the wheel, why not do what Matt said, and get yourself an AstoFlight servo tester? If you have any RC hobby shops in your area, you can probably find one, or you can order one off their website.
-- Gary
GGoodrum said:
I did completely remove the old pot on both servo testers I´ve tried.
And first off... I´m hardly trying to re-invent anything. I ordered a couple of cheap servo testers from Hobby King when I ordered other parts. I paid a couple of bucks for them instead of what? $25 for the Astro. I realize it´s not worth spending a bunch of time making something work but I am doing this for fun after all. May as well try to get the stuff I have working.
Second... I asked the question after I already had the testers.
Sorry, but I´m trying cheap stuff. So far so good.
I´ll just swap out the pot in the throttle. Then I´ll have a whopping $6.00 in the tester.
mani9876 said:
I have to admit I´m much better mechanically than I am with electronics. I´m learning but I was never really that into it before I got into e-biking.
The current tester I´m trying is this one: http://cgi.ebay.com/ws/eBayISAPI.dl...Category=34056&_trkparms=algo=LVI&its=I&otn=1
I´ll get a couple of pictures taken of it later. Thanks for the help.
I think I got it working. I simply added a 5k resistor to bump the throttle up to a total of 10k. It starts with 5k of resistance but the cheap controller I'm using on her bike simply uses that as it's starting point.
I noticed that whatever position you put the throttle at when you start up the controller is where it calibrates itself. Do all r/c controllers do this? I'll have to try it with my cc esc tomorrow. If so then it's a simple fix to use any pot throttle you want.
I noticed that whatever position you put the throttle at when you start up the controller is where it calibrates itself. Do all r/c controllers do this? I'll have to try it with my cc esc tomorrow. If so then it's a simple fix to use any pot throttle you want.
drewjet
10 kW
Your EV Warior throttle may not be using the full sweep of the pot. I have a finger throttle from a scooter that I really like. it uses a 10K pot but doesn't use the full travel. It effectivly is 0 to 5K, but is only good if you are using a controller that works with 0 to 5K. I am using it with a turnigy servo tester and ESC. Fortunately the Turnigy will do like you say and arm at wherever it sees when pluged in. I couldn't get my Castle 110 HV to do that.
drewjet said:
I think that's probably true. The EV Warrior throttle measures a bit over 5k so I'm guessing it's a 10k pot inside. I know the pot itself has more travel since you have to rotate it past it's stop point to take the throttle apart.
I had a bit of a scare with my bike tonight. I was done riding and dismounting the bike. I must have caught the throttle cable and somehow managed to pull two of the wires from my pot throttle that were soldered on to the servo tester. This resulted in the bike going full throttle. Luckily I had both hands on the handlebars but the bike almost flipped right out from under me. I was able to get a handful of brake just in time to stop it. Scary stuff.
Is there any fail safe thing I can do to stop that from ever happening again? I suppose I need a more positive way of holding the throttle cable so it can't be yanked on but stuff happens. I suppose a kill switch attached to the rider that pulls out if they come apart. I guess I'm hoping for a solution that would stop it from accelerating at all of the pot gets disconnected.
Is there any fail safe thing I can do to stop that from ever happening again? I suppose I need a more positive way of holding the throttle cable so it can't be yanked on but stuff happens. I suppose a kill switch attached to the rider that pulls out if they come apart. I guess I'm hoping for a solution that would stop it from accelerating at all of the pot gets disconnected.
drewjet
10 kW
You have to be carefull with these high power drives, they will bite. Just disconecting the Pot from the servo driver will usually not shut the motor down. You have to connect the negative to the signal wire to make it go to zero.
drewjet said:
Exactly, that's what I'm saying. I must have caught the throttle cable and yanked the wires right off the servo tester resulting in full throttle. I'm not sure how it happened. Maybe my shoe caught it was I was getting off the bike.
I guess the only thing I can do to prevent that in the future is to mount the throttle cable and servo tester in such a way where it's hard to yank the wires out.
And I agree, ya gotta be careful!
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