very weird problem

[alonstar]

Hey!
i have a Chinese 36-48V 350W controller (adding picture below)
When i connect my 48V battery everything works fine goes 34KMH aprox..
But when i connect my 36V battery it barely go over 13KMH and hardly drives me on it.
Anyone knows what it might be??

 

[Chalo]

How high is the voltage of your 36V battery when you're trying this? If it's high enough, the controller may interpret it as a deeply discharged 48V battery and switch to a "limp home" mode. Try it with the battery below 40V, and give the controller enough time between disconnecting the 48V pack and attaching the 36V pack for the capacitors to discharge.

 

[alonstar]

How high is the voltage of your 36V battery when you're trying this? If it's high enough, the controller may interpret it as a deeply discharged 48V battery and switch to a "limp home" mode. Try it with the battery below 40V, and give the controller enough time between disconnecting the 48V pack and attaching the 36V pack for the capacitors to discharge.

makes much sense i will try it out.
By steps i should empty the battery below 40V and then connect it to the controller and its enough or am i missing a step?

 

[E-HP]

makes much sense i will try it out.
By steps i should empty the battery below 40V and then connect it to the controller and its enough or am i missing a step?

As Chalo stated, you have to leave it unplugged long enough for the capacitors to discharge. It has to forget that it’s running on 48v and discharging does that. Leave it unplugged while you’re discharging the 36v battery; a couple of hours should be good.

 

[Chalo]

makes much sense i will try it out.
By steps i should empty the battery below 40V and then connect it to the controller and its enough or am i missing a step?

That should be enough to find out if the controller's protective features are the problem. Don't pull the 48V battery right off the controller and immediately substitute the 36V one; give it time to deplete the caps. If you have a display or an on/off switch, cycle those things while no battery is connected.

 

[alonstar]

h

How high is the voltage of your 36V battery when you're trying this? If it's high enough, the controller may interpret it as a deeply discharged 48V battery and switch to a "limp home" mode. Try it with the battery below 40V, and give the controller enough time between disconnecting the 48V pack and attaching the 36V pack for the capacitors to discharge

is there a way to discharge the capacitors? maybe if i touch the positive-negative of the controller without extranal power? it should spark and discharge?

 

[Chalo]

is there a way to discharge the capacitors? maybe if i touch the positive-negative of the controller without extranal power? it should spark and discharge?

That would do it, but it's a little risky to the plug and the the controller electronics. If you have a resistor you can use to short the controller power leads, that would be better. A two pin incandescent light bulb would work.

 

[alonstar]

h

How high is the voltage of your 36V battery when you're trying this? If it's high enough, the controller may interpret it as a deeply discharged 48V battery and switch to a "limp home" mode. Try it with the battery below 40V, and give the controller enough time between disconnecting the 48V pack and attaching the 36V pack for the capacitors to discharge

is there a way to discharge the capacitors? maybe if i touch the positive-negative of the controller without extranal power

That would do it, but it's a little risky to the plug and the the controller electronics. If you have a resistor you can use to short the controller power leads, that would be better. A two pin incandescent light bulb would work.

Hey thanks again for all your help.
my 36V is now around 39.4 and i connected it (after shorting the controller to empty capacitors) and now it wont drive. sometimes when i connect the battery it will give little push and then turns off. it thinks its an empty battery. what should i do?

 

[Chalo]

my 36V is now around 39.4 and i connected it (after shorting the controller to empty capacitors) and now it wont drive. sometimes when i connect the battery it will give little push and then turns off. it thinks its an empty battery. what should i do?

Maybe you have a 48V controller that has been misrepresented. Maybe once it sets LVC to 40V, it doesn't automatically recalibrate to a lower voltage battery. Whatever the problem, it looks like it won't be straightforward for you to switch back and forth between battery voltages.

 

[E-HP]

Can you provide an actual link to the controller rather than a screen shot? Your pic doesn’t show all of th wires and connectors.
I have a cheap controller that runs at 60v or 72v. It uses a jumper (two single conductors with a male and female JST) to set whether it’s 60v vs 72v.

 

[alonstar]

sure

Can you provide an actual link to the controller rather than a screen shot? Your pic doesn’t show all of th wires and connectors.
I have a cheap controller that runs at 60v or 72v. It uses a jumper (two single conductors with a male and female JST) to set whether it’s 60v vs 72v.

 

[alonstar]

sure

and the link

https://a.aliexpress.com/_oDZJ0X8

 

[alonstar]

t

Maybe you have a 48V controller that has been misrepresented. Maybe once it sets LVC to 40V, it doesn't automatically recalibrate to a lower voltage battery. Whatever the problem, it looks like it won't be straightforward for you to switch back and forth between battery voltages.

yeah i understand.
In my situation i dont want to switch between batteries, i will use 36V permanently.
thanks you for your help if you have any other ideas how can i reset it would be super helpful!

 

[E-HP]

and the link

https://a.aliexpress.com/_oDZJ0X8

Based on the installation instructions, that don't mention any settings for 36V vs 48V, it's probably supposed to auto-sense the voltage (between the 30V and 39V LVC). Defective.

 

[alonstar]

Ok everyone, i sent a message to the seller. he said to re connect the Self-learning wire.
it worked!
Thank you all for your help!

 

[E-HP]

Ok everyone, i sent a message to the seller. he said to re connect the Self-learning wire.
it worked!
Thank you all for your help!

Good info! Thanks for the update.

 

[calab]

The ignition wires have to be off for a few moments in some circumstances. I used hard wired ignition wires.

The reset problem has happened to me dozens of times, switching between 48 and 36v batteries with a generic controller. The controller just wouldnt work after switching. It was a 36v controller with using 48v battery first, then 36v battery. It never didnt work when I used the batteries up 36v first then 48v second, one at a time always!

Unplug battery wires to controller
Unplug ignition wires
^Plug in both
Then I'd connect the learn wires
& make the learn function spin the right way
Unplug the learn wires
all trail/path-side
ride on

Speed problems after switching batteries I have not come across that issue.

 

[Chalo]

Ok everyone, i sent a message to the seller. he said to re connect the Self-learning wire.
it worked!

Awesome! That's good intel to file away for a future problem.

 

[E-HP]

Awesome! That's good intel to file away for a future problem.

Yup, adding it to my FAQ. First time hearing that self learning does more than just the hall combos.