Battery Vehicle Society

i don't see any difference between those optos. the downside with both of them is the current transfer ratio (CTR) is really variable, 50-600%. so they could have extremely varying results, depending on which batch you got (like happened to me.) these might be better: http://uk.farnell.com/vishay/tc...

i agree a resistor pressed directly against the case might not be the best idea, but heat conductive, electrically insulating material is pretty common that could be stuck to the inside of the box. would give a little more room for error on resistor placement, as well. paul holmes has used it on his...

heat inside those boxes shouldn't be a problem, as the load resistors can be mounted so that they press against the inside of the case. this would work exceptionally well for ceramic resistors, since they have big flat faces that would offer a lot of surface area. a guy on endless sphere has been us...

yeah i can set it up and get a new pic. 2v/div on the y scale, what x scale do you prefer? should i stretch it out and just capture one with better res, or leave it compressed so you can see multiple slave signals?
or one of each

here is the new scope plot, using my sub-par opto's with 160 ohm resistors for R1 and R3. http://desmond.imageshack.us/Himg717/scaled.php?server=717&filename=scope3.png&res=medium still only just barely over 4.5 volts, but it's working on the bench. hopefully it will still work when i instal...

played around with it and got the speedo input and wh/mile calculations working. it should be accurate to 1 mile/hour right now, but i have to test the VSS sender and see if it's supplying 2 pulses per revolution, or four. might also mount the VSS to the motor tailshaft instead of to the drive shaft...

i'll do that shortly! just got it working on the bench so that it turns on the slave loads, i'm not sure why it wasn't doing it before. the only thing i changed is that i toggled the charger bit so it knew the charger was on, but it didn't automatically turn all the loads off when i toggled the char...

changed R1 and R3 to 160 ohms on every slave, and it's working perfectly on the bench now. thanks!

thanks for the confirmation, i'll get them all changed. i'm going to need to change R1 as well, but resistors are MUCH easier to desolder and replace than optos are :) also realized i only ordered 50 optos before, and each slave needs 2, not 1. so i'll order another 64 of the better optos and do the...

scoped the output on the master bus, this is what i found. this is from the first three slave boards, the problem child is now easily identified :roll: http://img62.imageshack.us/img62/7468/slaveoptosout.png added a second 330 ohm resistor in parallel with R3 on the third slave, and now i get this s...