Well it has been a while since I posted. I now have about 2,800 miles on my Triac who I have named Mack.
Mack is performing very well. I am driving him daily, and usually never get below 45% charge. I am going to try and get some video done and put on YouTube as soon as the weather gets better. Somehow video always looks better when it is not pouring down rain.
I have seen a lot of debate going on in the EV community on battery management systems, and I would like to put my comment out there. The biggest issue I have seen is over charging or over discharging. Lithium batteries will be damaged if you charge them to high, or drain them to far. The chargers I have seen appear to do a good job at charging without going to high. The big issue I see is with Battery management systems not allowing the voltage to drop below a certain voltage, and they are doing a bad job. And by bad job I do not mean they are damaging the battery. What they are doing is stopping or limiting the amount of power because of false readings.
Here is my understanding on lithium batteries. I am going to use Mack (my Triac) as an example, but it applies to all Battery management systems I have seen.
My cut off voltage is 2.5V per cell. That means if one of the 45 cells goes to 2.59V it will shut off to protect the batteries from being damaged. The battery can go below 2.59V under load as long as it is still above 2.59V at rest. When you are going up a hill drawing about 150-200 amps the voltage in the batteries will drop. I have seen it drop as much as .3V. If my voltage is at 2.9V, going up a hill could fool my BMS system into thinking my batteries are to low, and shut the car off, when in fact I have almost half a charge left. I have not run into this yet because I usually only drain my pack to 50%, and I do not have any hills at the end of my trip.
There is my long winded two cents on BMS systems. I think they are great used as a visual aid, but I would much rather not have it making the decisions for me until it can do a better job. The big problem is the small range of voltage from full to empty. Mack is usually at 3.3V per cell when charged, and 2.5V when empty. That is only .8V difference.