Small screen CA and Grin controller compatibility Q

Get all your technical information about electric bikes here.
Post Reply
User avatar
Ypedal   100 GW

100 GW
Posts: 12528
Joined: Dec 27 2006 12:55pm
Location: Moncton NB, Canada
Contact:

Small screen CA and Grin controller compatibility Q

Post by Ypedal » Sep 28 2016 11:08am

Hi guys.. i searched, and have emailed Grin but it's one of those " working on it now, need a quick answer " situations lol.

I have a recent grinfineon 20 amp ( 36 / 48 v) and on the label it says **DO NOT USE WITH SMALL SCREEN CA

Can anyone tell me why this is ? and is there something i can do ?.. i don't need any of the limiting features, just need the power data

This is the two button on the front panel small screen CA if that makes any difference ( vs the older, side, single button )
ES site status page:
http://www.ypedal.com/ES/ES.htm
----------------
http://www.ypedal.com

User avatar
teklektik   10 GW

10 GW
Posts: 4020
Joined: Mar 26 2011 1:15pm
Location: CT, USA

Re: Small screen CA and Grin controller compatibility Q

Post by teklektik » Sep 28 2016 11:42am

Ypedal wrote: I have a recent grinfineon 20 amp ( 36 / 48 v) and on the label it says **DO NOT USE WITH SMALL SCREEN CA

Can anyone tell me why this is ? and is there something i can do ?.. i don't need any of the limiting features, just need the power data
This is because of the changes in the CA-controller interface over the years. Although the connectors are the same, there was/is different assumptions made about the circuitry inside the controller and CA - specifically whether or not a diode was present to allow the CA limiting operation. The older small screen CAs did not have the diode and if connected to a new style controller will result in WOT and immediate runaway (!).

If you only want monitoring capability, simply disconnect the green throttle Override wire (pin 6) from solder pad in the CA or either side of the CA-DP connector.

[The extension bmp has been deactivated and can no longer be displayed.]

If you want limiting to work, you need only add a diode in-line with that wire someplace that's physically convenient. Just about any low power diode will work (1N914, 1N4148, 1N4001, etc). The cathode (little bar marking on the device) should be on the CA side so the diode arrow symbol is pointing towards the CA.

This extra diode will not hinder operation at a later time if you get a newer CA V2, but will prevent operation of a CA V3 - so be mindful of where you add it...
smallScreenCaFix.png
smallScreenCaFix.png (32.19 KiB) Viewed 514 times
Visit Grin Technologies at www.ebikes.ca
Build Thread: 2WD Yuba Mundo V4

User avatar
Ypedal   100 GW

100 GW
Posts: 12528
Joined: Dec 27 2006 12:55pm
Location: Moncton NB, Canada
Contact:

Re: Small screen CA and Grin controller compatibility Q

Post by Ypedal » Sep 28 2016 11:50am

Fantastic !!!!

Thank you good sir ! 8) 8) 8)
ES site status page:
http://www.ypedal.com/ES/ES.htm
----------------
http://www.ypedal.com

User avatar
Toorbough ULL-Zeveigh   100 MW

100 MW
Posts: 2592
Joined: Feb 09 2007 3:02am
Location: Marlboro

Re: Small screen CA and Grin controller compatibility Q

Post by Toorbough ULL-Zeveigh » Sep 28 2016 5:09pm

Just about any low power diode will work
1N34a?

User avatar
teklektik   10 GW

10 GW
Posts: 4020
Joined: Mar 26 2011 1:15pm
Location: CT, USA

Re: Small screen CA and Grin controller compatibility Q

Post by teklektik » Sep 28 2016 5:28pm

Sure.
The 1N34A germanium diode looks to have about Ifwd0=50ma, PIV=65V.

We are looking at a 5V throttle voltage and no more than 15ma forward current worst case (very much less typically), so well in spec.

The CA limiting operation will take care of any Vfwd (actually works fine with two diodes in series for setups where the controller had a diode and so did the CA). The low Vfwd of the germanium part is nice but in the end won't really be of material benefit. This is really a high frequency rf part and not my first choice, but use what you've got on hand...
Visit Grin Technologies at www.ebikes.ca
Build Thread: 2WD Yuba Mundo V4

Post Reply