I’m looking to create a retrofit device so that I can read the lowest and highest cell voltage values from the V2 controller. I also want to display under voltage and individual pressure difference warnings. I’m thinking about adding a microcontroller that connects to the throttle, ESC and battery CAN bus.
Battery CAN bus → microcontroller
ESC UART → microcontroller
microcontroller → V2 Throttle UART
V2 Throttle PWM → ESC (directly)
I will probably just add a few fields to the ESC UART package structure that the microcontroller sends out so the code changes to the throttle should be pretty minimal (famous last words).
Does anyone know if this is the right connector for the battery:
If it is, does anyone know where I can buy it? I reached out to ac-solutions and this was their reply:
A brief note in advance. A&C Solutions is Higo’s B2B partner in Europe.
If you are a consumer user, we recommend contacting your dealer. Unfortunately, we cannot assist you further.
Is the V2 controller RP2040-based? I’ve lost my situation awareness on the evolution of the controllers. From what I understand V2.5 is now ESP32-based. I have an early SP140 and was working on getting the RP2040 controller (2022 era) to talk to the BMS. I wanted to engineer a solution around the BMS hard-cuts due to a low cell voltage (often with sag due to load at low SoC). As far as I got was to have a friend fly-wire an unused UART of the RP2040 IC. Other projects then took priority.
I would love to chat with you. It looks like your goals are the same as mine, but your approach is different.
I was able to get a connector directly from Higo and it fits the battery. The cable faces toward the back of the unit, but it clears the motor and prop without any issues.
Control system goals:
My primary goal is preventing hard BMS cutoffs by proactively reducing output power. Specifically, I want to catch two conditions before the BMS trips: a single cell dropping too low, and excessive individual pressure differentials. I’m planning to use a PID-based approach so the system backs off power smoothly while still extracting as much usable energy from the pack as possible.
Right now, the unit can cut out abruptly if you slam the throttle even when the battery still has plenty of capacity — the voltage sag on a weak cell triggers the BMS before overall SOC is actually low. I want this handled automatically because full throttle is often a safety-critical input when you’re flying out of a bad situation and can’t be staring at the display.
Andrew — great suggestion on the motor temperature sensor. I’ll add that if I have bandwidth.
Platform & compatibility:
I’m currently building around the V2 throttle. If there’s enough interest, I’d consider buying a V2.5 throttle to support instead — that way you could upgrade an older unit using my retrofit kit plus a new throttle. That path would require some battery-side modifications that I haven’t scoped yet, and I don’t want to maintain firmware for multiple throttle versions.
If you’re interested in a retrofit kit, let me know!
In my case, the logs did not show any alarms until I had flown the unit for a while. Right now my battery is balanced at rest (at least after it sits for a while - I haven’t checked right after a flight) but under high load it will still trigger a hard cutoff for the above reasons - even at full charge.
There is more to it than that but I need to fact check everything so I make sure I’m not posting AI slop haha.
I don’t have very much time to work on this project and there doesn’t seem to be very much interest in a retrofit kit so I’m only going to make a solution for the V2 throttle. I’ll make everything open source when I can get around to working on this.
The part number for the Higo connector is S526AG A 00 B0 1000
The connector that I got from the manufacture faces outwards which is okay but it seems like it would be better if it faced inwards. Probably worth double checking before putting in an order
