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OBD II dongles for LeafSpy

Posted: Wed, 10 Jul 2019, 09:23
by coulomb
I want to be able to read the internals of my new-to-me Leaf, so I ordered a OBD-II Bluetooth dongle. (OBD-II = On Board Diagnostic version 2). The program of choice for this is LeafSpy, available for Android and IOS. To connect your phone to the car, you need one of these dongles. They come in Bluetooth and Wi-Fi varieties, but people are nervous about the theoretical possibility of someone controlling your car over Wi-Fi while you are driving it; at least Bluetooth has a more limited range. Bluetooth probably can't be accessed outside a metal car with the doors closed, though I haven't tried.

I did a little research before buying, but it seems, not enough. I knew enough to get one with Bluetooth V1.5 (they're up to V4.1 at least now), since that seemed to be what was needed for LeafSpy. I ended up getting this one, for $11:

Cheap OBD-II front.jpg
Cheap OBD-II front.jpg (39.34 KiB) Viewed 301 times
Below is the more expensive one (by about $4) that it may be designed to look like:

Vgate Scan.jpg
Vgate Scan.jpg (49.57 KiB) Viewed 301 times
When I went to plug it in, lo and behold I found an OBD II dongle already plugged in! Well, that's a bit of good luck, because presumably it is known to work with LeafSpy, and mine wasn't necessarily going to work. Indeed, after a bit of trial and error and some help from the seller (of my Leaf, not the OBD-II dongle), I found that I could get LeafSpy-Lite working using the dongle already in the car, but not the cheap one I bought. (I paid $11 for mine with free postage, it's since gone up to about $13). LeafSpy Lite is the free, limited feature version, recommended to get your dongle working. [ Edit: I'll be posting the Leaf seller's dongle back to them today. ]

A little more research indicates that for extreme cost cutting, the cheapest models don't have a separate PIC processor for handling all the commands required for LeafSpy; they squeeze the code into the Bluetooth processor, which has limited flash space. (I can't find the reference for this now; frustrating.) It seems that some clones don't even use a proper ELM327 chip, and emulate parts of the real chip in a tiny, cheap microcontroller. As you can see, there aren't many chips in my cheap version:

Cheap OBDII parts labelled.jpg
Cheap OBDII parts labelled.jpg (240.89 KiB) Viewed 301 times
You can see that the Vgate model is packed with more electronics, and even a larger antenna. The cheap one has no parts on the other side of the PCB (the side you can see through the translucent plastic case). The plastic case is much large than needed for the electronics. This is a nuisance, since in the Leaf, if you don't use an OBD extender cable, the dongle points downwards under the steering wheel, and people have reported knocking them out while driving.

So the take-home message is this: don't do as I did :oops:

I've ordered another dongle, for about $25.50 this time, which is much shorter, and according to my slightly extended research should work. I'll post the details when it arrives next week.

Re: OBD II dongles for LeafSpy

Posted: Sun, 14 Jul 2019, 18:02
by peter_mcc
I'm 99% sure the cheap blue dongle doesn't have a "real" ELM327 chip in it - they only appear to come in 28 lead DIP or SMD packages. ELM have had huge problems with people copying their design and calling it the same thing (ie counterfeiting). The quality of the counterfeits varies...

Some info on the "real" ELM327:

I got the recommended one from this place - it's on special at the moment. It hasn't arrived yet (and I don't have a Leaf yet!)

Re: OBD II dongles for LeafSpy

Posted: Sun, 14 Jul 2019, 19:51
by coulomb
peter_mcc wrote:
Sun, 14 Jul 2019, 18:02
doesn't have a "real" ELM327 chip in it - they only appear to come in 28 lead DIP or SMD packages.
Ah! I can see a 28-pin SMD package in the Vgate one. Also, the page you linked to specifies a 4.00 MHz crystal - the cheap blue one has a 24 MHz crystal.

If the real ELM327 really costs CA$15 in 1000+ quantities, then it's obvious that the AU$11 models can't have that chip inside. In fact, my AU$25.50 model probably doesn't have one either; in fact it wouldn't fit! I'll just have to hope that they emulate it well.

Re: OBD II dongles for LeafSpy

Posted: Sun, 21 Jul 2019, 11:41
by coulomb
I ended up getting this one (but a different colour):

Konnwei KW903.jpg
Konnwei KW903.jpg (25.69 KiB) Viewed 213 times
It works fine with LeafSpy Lite, but don't try to pair with it on your phone; it will refuse pairing. Instead, inside LeafSpy Lite, you select "Bluetooth 4.x LE" from the "Select OBDII" menu (tap the menu icon at the top right of any screen, like an equals sign but with three lines). For me, it searched for the dongle and found it in a few seconds. This seems to be the recommended type of dongle now, and this Konnwei KW903 model seems to be the cheapest of this dongle type. It remains to be seen whether it will keep up with logging and other activities that demand high throughput, although I logged a short granny charge successfully.

Alas, when I bought LeafSpy standard (not Lite, not Pro), it didn't have the "Bluetooth 4.x LE" item on the "Select OBDII" menu. I emailed the author using the address in the About & Help menu (WattsLeft dot meter at gmail dot com), and he replied with a URL to join the beta test group. I accepted, and then the app updated (I found I could force an update on my Android phone using Settings / Apps / LeafSpy / App details). So now I'm running test version 0.34.48 instead of the release version 0.34.42. The "Bluetooth 4.x LE" menu item appeared, and it immediately connected to my dongle.

[ Edit: corrected spelling of Konnwei, model KW903 ]