Yes, that circuit is pretty much it, for the LVC circuit. Just the TC-54, an 820 ohm resistor and the CNY-17F optocoupler, for each channel. In the BMS, and the later versions of the LVC boards I've done, we use a dual-channel ILD2 optocoupler, one for every two channels on the LVC. For the BMS, half of the ILD2 is used for the LVC, and the other half is used for the charger control logic.
Unless you have a space problem, I'm not sure why you would need to separate the LVC out from the rest of the charger control logic in the BMS. The LVC circuits work completely independent of the charge control logic, which is not even enabled unless the charger is connected, and on.
I have an updated, LVC-only board that I have ready to get made, but I'm just not sure there's much demand for just the LVC board. I could do a small run of these, but that makes them pretty expensive, so I'd have to charge about $25-$30 each for them. Here is the layout:
This uses the same "tear-off" feature to support any number of channels up to 24. It also includes Randomly's active cutoff circuit, which doesn't have to be populated if not used. Actually, you can simply break off how ever many channels are needed from the right side of the board, if the active cuttoff is not needed. If active cutoff is needed, by using a pair of 4110 FETs, it will handle 100A+. It draws next to nothing in standby current.
Anyway, if there is enough interest, I'll get these done this week.
On the BMS front, Richard an I are working on a slightly updated version. The big change here is that the new version will now also support using other Lithium chemistries, like LiMn/LiCo, simply by cutting a jumper for each channel. Actually, the jumper will be simply a through-hole connection pad, so all that need to be done is the holes would need to be drilled out to break the connection. What this will do is change the LVC cuttoff from 2.1V up to about 3.0V, and it will change the shunt cutoff from about 3.68V to 4.18-4.19V.
We are also adding a couple parts to the 12V regulator circuit so that much larger pack voltages can be supported. I think the limit right now is about 72V. but now it should be able to support up to a 48s/144V pack configuration.
Finally, I'm thinking about adding Randomly's active LVC cutoff circuit to this version, as I continue to get requests for this feature for some who want to do 12V and 24V SLA replacement packs, which need to be stand-alone (i.e. -- no ebrake/throttle cutoff on the controller...). What I'm thinking is that can add it to the far left part of the board, and add the "tearoff" holes for those that don't want active cutoff. The other option is simply to do a separate 4/8-channel version, with the active cutoff.
We are alos working on the surface mount cersion of the BMS. After we fully test the new version, we'll finish up the conversion, and get fully populated boards done. This will still be a couple of months away, before we can actually have them ready to sell, but this is the path we are on.
Anyway, I hope to get this new version in for production early this coming week. Because we are so close, I've decided not to do another run of the current version (v2.2), so for those still waiting for these to be back in stock, you will have to wait another week, or so.
-- Gary
I hope to get it finished tonight still, and submit it in the morning. That would get the boards back to me by Thursday.
