Voyage Systems: Megan and Minnie

[xsynatic]

Assuming Minnie has the same Tabs in the “expert” tab (i only own a Megan), then you could try changing the “Minimum Wi-Fi signal strength”. I set mine to -90 after i had some trouble uploading records. Issue has been fixed since that change.

[patrickcleary]

@xsynatic

“Minimum Wi-Fi signal strength”. I set mine to -90

I scrolled right past it a couple of times & didn’t mentally register the need to change from its default.

Thanks for the tip! Will see if it auto uploads after my next ride.

Edit: It veerks!

[macfly1202]

Hi, I’m using metr Minnie on my eFoil now since 2 months and I’m so happy. It’s far more excellent than features descibed on your website. Thanks. But I have an issue with apple watch - not really an issue but when riding eFoil, metr.app on apple watch (7) goes in background - not stay on 1st level application and I don’t understand why. Is there a way to have same behavior other sport app I mean application (sport, waterpseed) stay in first plan (always active ?) - hope to be clear enough - Regards from France

[fessyfoo]

@fessyfoo

Just had a convo in vesc discord leaving me less sure any of it is more “right” than the other.

PWM vs PPM vs Servo Control: Vesc PPM app is named wrong.

Aafter a bunch of internet research into how the control mode the PPM app is using is normally referred to here’s what i’ve found: Servo Control the vesc PPM app doesn’t decode PPM. it decodes “servo control”. which is a defacto standard without much of a name. but under the name servo control it does have a wikipedia page. PWM most commonly that protocol is referred to as PWM by RC manufacturers. but importantly it’s not “full PWM”. Servo control does not expect full duty_cycle n…

Servo Control > PWM > PPM (PPM is just totally wrong)

[patrickcleary]

In ride logs, how does one identify which logical ESC corresponds to which data trace?

For example - my board is a 4WD and so has four logical ESCs linked over CAN. When I expand individual traces for motor temp and motor current, this is what I see:

Intuitively I think the first two correspond to my front motors, since they show lower current during accel and higher current while braking. But how does one know which specific ESC corresponds to which trace?

I initially thought they were in ascending order of CAN ID - mine are 50, 55, 60, 65 for FL, FR, RL, RR. But then I saw this VESC error and realized it may not be the case (unless Metr ESC IDs start count at 0):

[BenjaminF]

@fessyfoo

Servo Control > PWM > PPM (PPM is just totally wrong)

I dont care what @janpom calls it, as long as Minnie can log it

[fessyfoo]

@BenjaminF

I dont care what @janpom calls it, as long as Minnie can log it

@fessyfoo

we should update the vesc code to send a standardized throttle input value in the regular telemetry packet. vesc remote or ppm[it’s PWM!] (or adc?)

yeah and in the back of my head I keep thinking we should make this easier
to log upstream.

I appreciate that metr has made the special telemtry request to get it.

[rpasichnyk]

In case Megan / Minnie is connected to CAN bus, the data traces are arranged in ascending order of CAN IDs, your assumption was correct.

Regarding the faults, you also guessed it right, ESC 3 means, ESC with index 3, and those start with 0, so in your case it’s ESC with CAN ID 65. We should improve that and display CAN ID instead of index.

[rpasichnyk]

We didn’t have enough time to work on smart watch support recently, sorry about that. It’s a big investment time-wise and unfortunately “make and forget” approach does not work, Apple and Google constantly change the requirements and SDKs, it’s tricky to keep up. We will try to improve smartwatch apps in the future.

[Ash]

@rpasichnyk

We should improve that and display CAN ID instead of index.

this reminds me of when elon was talking about the thruster system for starship and realizing improvements to be made in real time.
thanks for the work y’all are doing to improve everything

[rpasichnyk]

We have now added PPM logging + realtime data support for Megan / Minnie. For now in Beta firmware (v0.17.17), please give it a try! Make sure you have updated Metr app to latest as well.

[BenjaminF]

That was remarkably fast! Thank you so much!

[Kodin]

Just ordered my Megan, have a few questions - I have an old Metr CAN with the LTE module; I’ll probably re-use the LTE radio on the new Megan setup; Since I find myself building two boards at the moment, I’ll eventually want a second Megan, and preferably, I’d like another LTE modem… Is it still possible to do a production run of these if they are otherwise sold out? How much money do I have to pay to make it worth the time/effort to produce them again?

Second question, or rather, first feature request: JKBMS support? Some pretty nice BMS’s with active balancing, up to 300A discharge, and up to 2A (non-simultaneous) active balance current capabilities, (discharge highest voltage cell through transformer into lowest voltage cell,) with uart, RS485, CAN, some have battery pack heater control support for cold weather, etc…
(Main reason I ask is I already have a few lying around)

[Kodin]

48S isn’t nearly as ridiculous when you run LTO or sodium ion cells in a pack… 40S LTO is only 92V

[rpasichnyk]

@Kodin

I’d like another LTE modem… Is it still possible to do a production run of these if they are otherwise sold out?

We still have about 20 of those! Will add to the shop during the weekend.

@Kodin

(discharge highest voltage cell through transformer into lowest voltage cell,)

This is cool! We will have a look.

[Kodin]

There’s two types of “active” balancers/equalizers - Capacitive, and transformer based. Capacitive charge a cap from a high cell and discharge into a low cell with a bunch of mosfets in the mix. Transformer based units transfer power between the high/low cells one pair at a time via a big toroid transformer with as many taps as you have cells. Daly makes some active balancers that are self-contained, and JKBMS has all-in-one balancer/BMS units.

[Kodin]

If it helps, here’s a reference for a JKBMS CAN implementation for ESPHome:

GitHub - Sleeper85/esphome-jk-bms-can

I’ve also reached out to JKBMS via email to request developer documentation on protocol, command list, etc…

EDIT:
Oh wait, nope; they implement canbus on a esp32 to talk to an inverter, but talk to the BMS via UART… Still, interesting, but not what I was actually looking for. Hopefully the manufacturer emails back with more useful information. Also, forgot to mention most models have bluetooth.

EDIT 2:
From this doc:

• GitHub - syssi/esphome-jk-bms: ESPHome component to monitor and control a Jikong Battery Management System (JK-BMS) via UART-TTL or BLE Thanks go to syssi for help and making the original RS485 code!
• JK-B1A24S / JK-B2A24S Active Balancer | Second Life Storage & Solar
• GitHub - jblance/jkbms: repo with attempts to test connectivity to JK-BMS via BLE
• jblance/mpp-solar#112
• mpp-solar/mppsolar/protocols/jk232.py at master · jblance/mpp-solar · GitHub
• mpp-solar/mppsolar/protocols/jk485.py at master · jblance/mpp-solar · GitHub
• GitHub - sshoecraft/jktool: JIKONG BMS Linux command line utility
• https://github.com/Louisvdw/dbus-serialbattery/blob/master/etc/dbus-serialbattery/jkbms.py
• Decoding the Smart BMS Protocol | Jake’s Blog

Hope this helps some if you’re interested in implementing! I’ll update in this thread if I get a response back from Jikong regarding my documentation request.

[rpasichnyk]

@Kodin

I’d like another LTE modem… Is it still possible to do a production run of these if they are otherwise sold out? How much money do I have to pay to make it worth the time/effort to produce them again?

Metr LTE

[patrickcleary]

Gosh, Roman. This module looks so freaking cool!

Can I have your $0.02 (or kr0.21 I suppose) on a valid setup with Minnie + Metr LTE to provide 24/7 GPS tracking?

My Minnie came with a really tiny GPS module (Beitan BE-180). I assume it’s UART by the silkscreen (TX/RX). Fortunately, module size is not a constraint as I have plenty of space in my enclosure.

I understand from Metr LTE docs that, for 24/7 GPS tracking to work, either of these scenarios are valid:

1. GPS via Minnie: BE-180 UART GPS module plugged into Minnie’s UART port. 5v UPS (fed by drive battery) would connect to Minnie’s upstream CAN port 5v & GND pins. This would also power a Metr LTE plugged into Minnie’s downstream CAN port. Minnie + Metr LTE would remain “on” all the time.

2. GPS via Metr LTE: BN-250 CAN GPS module (source) plugged into Metr LTE’s downstream CAN port. 5v UPS (fed by drive battery) would connect to Metr LTE’s upstream CAN port 5v & GND pins. Minnie would sit upstream of Metr LTE. Therefore, only Metr LTE would remain “on” all the time.

Would you recommend I get a Metr LTE with GPS module, or should I use the one I already have?

I.e. Does the larger module offer some improvement in reception, etc? Or, will using the smaller module - and thus having Minnie on all the time - draw significantly more “standby” current?

[xsynatic]

@patrickcleary

GPS via Metr LTE
Therefore, only Metr LTE would remain “on” all the time.

Metr LTE need an active connection to some other main Metr/Voyage device to work.

So both Metr CAN/Minnie and the LTE need to be powered. Connecting the GPS to either devices is fine.

Roman please correct me if i’m wrong.