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Originally Posted by NeilBlanchard
Thanks for that info - I am a newbie to all the technical stuff on EV's. Does the Orion actively balance the pack while it is in use? One of the things I have been told consumes some energy is when BMS does this. And also, some BMS units shunt the excess energy to ground when a particular cell is fully charged, and a few divert it to other cells that are still charging.
As I understand it, both of these are advantages of bottom balancing the pack.
I totally agree with you on regen, and the way you have implemented it is exactly how I like it. Only the e-Golf and the Fit EV in Eco mode, have coasting. Does your car require you to hold the "shifter" to control the regen, and if you let go of the lever, does it return to coasting?
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The Orion does not balance cells while the car is driving. When the charger is running and cell voltages are rising, the Orion will put a tiny bit of resistance on the cells that are filling up the fastest. The point where the Orion begins to add resistance is user programmed, so you can tell it when, if at all, to do it. The Orion will shut the charger off when the first cell reaches whatever value you program in, and then will continue putting resistance on the high cells as the pack settles, until a second user programmed point is reached, at which point it no longer puts resistance on those cells. I set this rig up so that as my pack is charging, it puts resistance on each cell as it passes 3.42 volts, and then the Orion shuts the charger down when the first cell reaches 3.55 volts. I set the Orion up to continue to put resistance on the high cells as the pack settles to resting voltage, and I programmed 3.40 volts as the stopping point. Once the last cell settles below 3.4 volts, the Orion is no longer doing anything. The amount of energy lost to balancing is very trivial, and would be expressed in milliamps.
As for the bottom balancing thing, there is a never ending debate about bottom vs top balancing. With all due respect to the knowledgeable folks who support bottom balancing, I do not believe that they understand the implications of an Orion, and still look at it as just a "BMS". Although I am not fond of the Prius, I do respect Toyota's educated decision to use a 16 cell version of this on the Prius. They have invested a lot more money than I have to go with this top balancing technology, and they are more up to date than the bottom balancing crowd. To me, the Orion makes bottom balancing look like obsolete practice.
As for holding the shifter button to maintain regen, that is exactly how it works. I can push the button as much or little as I want during a non regen coast, regulating the regen level, and when I release the button completely, it is back to no regen coasting that feels like a car that is in neutral.