AEM VCU-200 anybody running it successfully

Some random extra info I've gotten direct from aem over email or from talking to aem people at Holley high voltage....take all of this with some salt.

Their BMS system (currently in development but very close to release) is master/slave based which saves a lot on huge wiring looms. They all just sit on CAN so ideally each slave only needs two wires going to the rest of the system instead of like, 16.
I want to say they're shooting for like $1600 for a set of one master and 5 slaves, which would cover 108 total cells. That seems expensive for the number of cells covered though, but Orion costs like $1200 for a set of 96 so maybe it isn't too bad. Also I think they only do discharge balancing, since I don't think they'll have a power line to do charge balancing

They're working on CCS fast charge support, [edit; it will be some kind of addon module, not something the bms-18 will be able to do with a firmware update], and they're doing software work now to support it (mostly around really tight temperature monitoring, requiring a chiller in the battery cooling loop etc).
The support will be rolled out in phases as they validate it. 50kw max at first, then slowly opening it up as they validate it can safely do that with most batteries.
However this is still deep in development so, no idea when this'll be.

Their PDUs (little satellite power units which can switch accessories and stuff) I believe have multiple PWM pins, so they can be used to run basically everything including cooling pumps and fans and power steering pumps, all over CAN from the main unit. They're 8 channels each but $800 per unit which seems a little high. I want to say they can also run contactors but that might be something the VCU does directly.

So, for a moderate price increase per piece of hardware you can cut down a hell of a lot on wiring and abstract a lot of the fiddly shit, which sounds gr8 to me.

Might be boned in my conversion, at least when it comes to the bms-18

Discussing with the techs over email, it seems like the vcu200 can only have one bms-18 connected to it? Meaning my maximum number of cell taps tops out at 108 which seems low

The newer LG chem bricks seem to have a minimum of 13 cell taps coming out of them, 12 bricks x 13 cell taps is 156...and the older LG chem bricks have 16 taps per battery so 196(!) Connections.

They're saying having two parallel strings of these bricks would be not a great idea, and better to parallel then at the cell level and have one tap per paralleled cell, gives you better power output which would also equate to faster charging (yay)

They drew me a fancy diagram to illustrate, attached (below is the default battery, and what I thought I was going with)


However I don't think making them parallel at the cell level is feasible, it may not even be safe

I think I'm just missing something here, but a max of 108 taps per install seems to massively limit the flexibility of the system, which doesn't seem like something aem would do. For instance that design completely cuts out the Chevy volt packs, I think that also rules out some larger configurations of Tesla modules? That can't be right.

Since this is sort of becoming a VCU200 support thread

Anyone find it weird that while the precharge and positive contactors are driven directly by the vcu to close, the negative contactor control connection just connects to ground when it's active? Meaning you need to get a relay to trip to actually power the coil on the negative contactor to close

That seems weirdly obtuse to me, is there some safety case I'm not thinking of?

Also does anyone have a single negative contactor for their entire system with positive contactors to turn on various other systems as needed, or one negative contactor for the charging and HVAC systems with another for the traction systems?

So there's no chance of a roll-away while charging

Edit;
Email to the AEM guys seems to imply that the normal port doesn't push any amps but they use a pdu-8 internally to drive stuff like that

I'm....trying to avoid buying even more AEM stuff but I guess a pdu8 would be handy to drive all the contactors and cooling fans/pumps, high voltage AC compressor, etc