Need advice on upgrading amps on controller

[Wesyeed]

Hi, long time lurker. Decided to join up because I'm in a bit of a jam right now. I built an ebike, bought a 2000w kit from high powered cycles. Their service is excellent, I don't care what anybody says. Couldn't be happier. But yesterday I was just going to the library to do some studying on Einstein's theory of relativity (because I felt like it) and I left my bike out in the rain. Long story short, it appears the controller got water damaged. From reading the board it seems to be something called the mosfets. Well I'm glad it wasn't the motor or the battery that was busted. I dusted off my old voltage meter and tested the battery, still giving off 52 v of power, no prob with that. I have to conclude the controller's just dead. I figure i'll just replace the controller and be back in business. Problem is, I go to purchase my controller a 48v-25a sensorless controller and they're out of stock. All they have is the 40a version. Would going with the 40a be a problem? From what I've read about it, seems like it'd give the motor more juice but drain the battery faster? I dunno.... Any advice would be much appreciated.

 

[mwkeefer]

You should be able to program any decent controller to adapt it to fit your needs, if you can't program what they are offering then I would look elsewhere like Ed Lyen or a Methods or many other possible locations... Then you can program in your own current limits.

If you want further assistance with this, or determining settings then we will need to know the chemistry of your battery, the C rate and capacity in AH and also more information about your motor, geared or direct drive hub, average top speeds on old controller, etc.

You are right more amps would be quicker performance (more torque, faster acceleration) but the trade off may be more than faster battery depletion it could in fact burn out your motor if too much power is applied.

Since you mention "sensorless" I presume the motor doesn't have hall sensors (a connector with 5 tiny wires)?

Regards,
Mike

 

[Wesyeed]

Nevermind. I found it at electric rider. Though thanks for taking the time to help, didn't know more amps could burn out the motor, I'll play it safe and stick with 25a. A mod can close this if they wish. Thanks again.

 

[agniusm]

You said you purchased 2000w kit. At 48v and 25a it is only 1300w so if you will get 40A controller it should be fine case 52*40=2080w

 

[Kingfish]

Glad you found replacement. Although to complete the answer...
The simplest way to upgrade a lower-amp controller to accept more are:

• Upgrade controller traces. These can be easily upgraded with a soldering gun and larger wire. Upping to 12- or 10-AWG will significantly improve the bottom-end and add torque.
• Buttering up the shunt(s); applying a bit of solder to increase current handling. It doesn't take much, so go lightly.

12-FET with wimpy wire pulled off and replaced with 10-AWG stranded.

Lesser factors, though important are:

• Higher current-capacity connectors. Something like 45A APP, or HTX 4mm, or EC5 :wink:
• Battery & Phase wire gauge upgrade. At least 12-AWG, though 10 is better

These are some of the earliest mods I learned to create, and they are well documented by ES Graybeards.

Enjoy! KF

 

[wesnewell]

You can change controller max amps by cutting shunts to lower it or modding them to increase it.
http://endless-sphere.com/forums/viewtopic.php?f=2&t=31643