Quote:
Originally Posted by e*clipse
First qualification: I haven't read the whole thread.
Issues that bother me:
1) Isolation. What is the rated voltage? Yes, there is one. Remember, we're talking about 650V here. Many isolators, etc have voltage limitations far below that.
|
It uses opto isolators. So you would just have to ensure the electrical isolation of the one you use is appropriate to the pack voltage you are using.
Quote:
Originally Posted by e*clipse
2) GND is local - the cell's local ground, I assume. This is ok, BUT data must be completely isolated from GND. (see below)
|
As with item above, uses opto isolator so no sharing of grounds etc. The two wires from the data out of one cell provides a voltage to drive the led in the next cells opto. So the opto's isolation rating is the cell to cell isolation rating providing the layout is appropriate and the opto pins are well separated from other components.
Quote:
Originally Posted by e*clipse
3) Dout is near the cell's voltage. That is fine when we're talking about cell 1. how about cell XXX - the one near 650V??  |
With higher voltages would come an increased attention to layout. On large Ah cells there is more than enough room to keep things well separated. A 650V pack is probably less common than a 144v pack and so the builder would (i hope) be aware of the higher isolation requirements of anything they built.
Quote:
Originally Posted by e*clipse
4) Any safety for the balance resistor's control? If it locks on, any sensor or override? Lee Hart has some excellent suggestions about this.
|
There was some discussion in the thread as to how best to implement this. Some were talking about adding fuses. I have the LED and resistor in parallel with the load resistors so i get a visual indication of when the cell is being loaded. Then there is the master module which monitors the each cells voltage and turns on the error led if there are any problems. If the car is unattended (charging) it wouldn't be difficult to wire up the error led output so that it sounded the car horn or something equally noticeable.
