throttle or controller problem???

hi there everyone

im having some issues with my throttle speed switch


when i got everything running to start with, the bike ran as it should-the low, med and high throttle settings all giving their desired results.

after about a week and a few rides things got weird-

cuttoff at full charge and strange throttle behaviour- low and med giving the same med speed, high setting giving low speed




iv properly balenced and changed to 16s2p for 20ah(headway)-same result, although no cuttoff as yet, just the funny throttle.



the odd thing is this does not occur when bms is removed and bike behaves normally.


perhaps its something in the controller?? (18fet 65Ainfenion from cellman)-but why does it only occur with the bms in the system???

anyone had similar experiences??

any help much appreciated

This does sound odd, but it's hard to know the cause for sure. Maybe someone more experienced than I will have something better to say. First thing I'd do is immediately order a spare of both the throttle and the three switch and maybe a controller if you can afford it. If they are busted some how, you'll need to replace them, if they aren't busted, then you at least have a spare or something to test against. One of the easiest methods of troubleshooting is a swap method. You replace a single part, and then test things out, if the run like normal with the swapped part, it's likely right to say that the part you swapped is the culprit.

I would check the plugs of both the switch and the throttle, if the pins look okay and appear to be seated correctly and not bent out of place or something like that, I'd unplug and replug them 5 times or so. If you have some bent pins, it should be pretty easy to gently bend them back. If replugging the throttle and such fixes it, you probably have a corrosion problem, a little dielectric grease may prevent this problem from reoccuring.

If you are still having an issue, remove the three switch. From my experience, some controllers are set to whatever throttle % medium is set to by default without the three switch in place. You can change this and other settings by programming the controller. If removing the 3 switch makes it run at whatever speed by default (program default to be wide open throttle if you can), then that may suggest that the three speed switch was the culprit. If it still runs on low, it might be the throttle. Do you have a watt meter of some kind? That would be good to have. I might recommend the cycleanalyst v3. It has a lot of neat features, one of which is a throttle gauge which would tell you if the throttle is actually getting to 100%.

If this is a controller issue, I'd have no idea how to tell, I'd start with the switch and the throttle first. You could open up the throttle and the 3 speed switch and check the continuity with a multimeter. http://www.ladyada.net/library/metertut/continuity.html

If you don't have the cable to program your controller, put that on your list of things to buy that I just suggested. Having spares of things can be an extremely good thing. It would sure suck to be sunk on riding for days or weeks because of something as simple and cheap as a busted throttle.

Thanks very much for your prompt reply bowlofsalad.

sound advice.

i do have another throttle (simpler,no speed switch ,so far never used it) and also another controller,but 24fet which im not sure will work with 48volts as it has a lvc of 60 volts or something.-may be time to give it a shot.

just a few plugs to swap first to be able to connect to current system.....

but the really strange thing is everything seems fine as long as i bypass the bms-run the battery lines straight to the controller,throttle works just fine.

so this seems to me to rule out dodgy speed switch/throttle.



yes, the program cable is also on my to-do list. i also have a new cav3 but it limits the bikes speed to 5kph by some highly annoying setting unknown to me so i dont use it riding yet. cellman also recommended routing the throttle via cav3 for better results, rather than straight to controler. cav3 seems so complicated though.
also listed for future tinkering. :?

by the way, is it possible to make a usb programming cable diy style?or not worth the hassle?

thanks again

ridethelightning said:

hi there everyone

im having some issues with my throttle speed switch


when i got everything running to start with, the bike ran as it should-the low, med and high throttle settings all giving their desired results.

after about a week and a few rides things got weird-

cuttoff at full charge and strange throttle behaviour- low and med giving the same med speed, high setting giving low speed




iv properly balenced and changed to 16s2p for 20ah(headway)-same result, although no cuttoff as yet, just the funny throttle.



the odd thing is this does not occur when bms is removed and bike behaves normally.


perhaps its something in the controller?? (18fet 65Ainfenion from cellman)-but why does it only occur with the bms in the system???

anyone had similar experiences??

any help much appreciated

Click to expand...

BMS problem.

Swapping the battery and finding that the problem vanishes with a different battery would probably mean there is a problem with the battery you removed.

The cycleanalyst is indeed a bit complicated, have you gone into the menus and made some adjustments? Is the rshunt value set correctly? Spend some time reading the manual for the CA, you may have to read sections more than once.

yeah the cav3 is quite a complex animal, menues within menues, and settings affecting other settings...i realy wanted v2.3 but got v3 with cromotor special from methods.(although im currently running hs4065)

im sure i can figure it out some time soon but want to get basic stuff sorted first.iv set the shunt r value to .77m ohm as advised by cellman, also voltage ,amps etc. it s really noticable it wont allow power imput as soon as speed goes over 5kph or someting.

battery problem? it seems pretty ok to me, all cells charging ok, and with 2p id thought there couldnt possibly be enough sag to cause current limit at full charge, 53.9V, even when not under load.....unless there was a really dead cell... hmmm more battery tinkering coming up.

under load the voltage sags to 52or51v almost emediately.(Says cav3 at 5mph)

ill try to get another battery on to it to see if theres anything going on there

im a complete nube at this,got a lot to learn, its great to get advice so easily, thanks heaps bowlofsalad.

i found the problem!!!- bent throttle plug spade. your suggestion to take a good look at the plug was spot on!
something so simple...so much trouble..check the obvious first!

thanks again B.O.S for your help

ridethelightning said:

i found the problem!!!- bent throttle plug spade. your suggestion to take a good look at the plug was spot on!
something so simple...so much trouble..check the obvious first!

thanks again B.O.S for your help

Click to expand...

I am very happy for you, happy trails.

Don't forget about the swap system, it would have saved you this headache and may very well save you ones in the future if used correctly not just in this situation. Example: Throttle A doesn't work, throttle B does work, inspect throttle A with extreme focus and patience and hope the problem shows itself to your powers of observation.