I actually believe it might be using FOC for low speed torque control. The boards are dead silent until you get around 11mph.
I cannot speak for the ESC since i haven’t seen the top or bottom of it, but the BMS system is incredible both in physical design and hardware. Essentially the 12 cells are welded with outward extending tabs. Thus the PCB slides on top of the battery such that the tabs fit through the PCB and are soldered then and there (virtually no balance leads), I believe each cell may feature thermal sensors, etc. Boosted’s use of the can bus isn’t just to relay battery status. Their PIC based ESC has a primitive elegance at the ESC side making it a very inexpensive component to repair and replace. I believe that unlike the VESC which burns out all the time, the processing and bluetooth radio/nunchuck/remote and primary functions such as the odometer are actually integrated into the STM based BMS which is in a watertight container.
The ESC is very expendable and costs very little to replace because the BMS unit is the actual processing unit/brain. The ESC acts like a trained muscle - take input and modulate motor speeds and report back to the battery.
This is how an electric car works - its focused on the battery side, not on the motor side. Motors are cheap and easy to replace, batteries no so much. Their use of automotive grade components and design is not a coincidence.
I don’t remember where I saw it, but boosted stated somewhere that their controller runs in BLDC. The sensors are why it has better torque at low speeds. Any specialized specific design should be better in a sense than a generic design. The tabs sound cool. But if a cell breaks, it can be more work to replace.
I’ve had issues with low quality vescs, never with a chaka vesc. I have 8 chaka vescs, and never had any issues. So to say they brn out all the time is not true.
How is the ESC expandable?
And why would you do logical processing on the BMS?
The ESC is generally the brain. When your doing calculations, you want the shortest bus possible. Separating this to the BMS via cables from the esc would slow the processing speeds way down (this is why you have multiple layers of cache on a processor for example)
Yea I doubt this is case too. Their ESC looks like a full fledged unit to me. The BMS is also a smart BMS that lets the BMS and ESC communicate with each other.
I’m thinking about this from a cost perspective. When my board comes back with new motors, I plan to measure the Bluetooth signal. I suspect it’ll be inside the BMS.
Nevermind then. Voltage sag will continue to be a pain in cold weather.
No. Your listening to the buck converter switching action and probably some degree of harmonics caused by the EMF of switching system.
I suspect their cell quality suffered from counterfeit A123s OR the cell ratings for dis/recharge 18650 have a fraction of the 26650 dis/recharge and their math didn’t account for this some how. Weird thing is, LiFePO4 can take a LOT of abuse before they get dangerous. Its a real mystery.
100% doubt they are counterfeit. They buy directly from A123 at this point. Tens of thousands of cells can be purchased directly.
LiFePO4s only last a few charge cycles if overcharged to 5v.(US Military study did an overcharge test with A123 18650s) If they are not limiting the charge current properly on the 50v charger, then the LiFePO4s will be charged to 4.2-4.5v. After about 10 charge cycles I am guessing that the cells are deteriorating enough to vent with little current draw.
The new charger is 54.4v that’s basically 13x 4.18v logical for boosted to not charge there batteries to 4.2v. Boosted said 199wh so 13s2p of 1.8ah batteries sounds great. or they are using 15s lifepo4 safer and better life cycles and what they currently use. the reasons for increasing voltage, basically if they have a torque control ESC then they can draw on the voltage and also stop voltage sagging from reducing the top speeds that they provide. Every thing is regulated. You buy a v2 with a 99wh battery the pack is still the same as the V1 but the charge voltage is 54.4. They have 2 depths of the charging port one for 43.2v so you can use your V1 charger and the second for 54.4v that runs through a regulator to then drop the voltage to charge the cells.
The v2 has gone away from a decoder and now use hall sensors. Basically sanjay told me that it was a cost compromise and they felt that the control they can get from hall sensors is still great because there ESC is made for 1 motor so they can dial in on settings and others tellemitry.
In the v2 the have a larger diameter stator but shorter. This wasn’t so much about torque increase it was about heat while using a sealed motor and while increasing the amount of plastic they used on the motor mounts to again to reduce cost. The V1 mounts where heat sinks.
This is the thing that differs many companies every one is trying to get more power, range, reduce weight while boosted are refining what they have. There battery issue sucks but there service has been great. Evolves mounts snap (could be just as bad) and they say nothing about it.