DIY Electric Car Forums banner

AEM VCU-200 anybody running it successfully

16724 Views 81 Replies 21 Participants Last post by  mlrtime99
I've been watching the AEM VCU-200 for a while now, but I haven't found anyone to successfully run it besides AEM in their black mustang and when they redid the EV West van. But I am assuming that both of those took forever to work and I am not really interested in being their guinea pig.

Is anyone running this and how hard was it to setup?
1 - 15 of 82 Posts
Throw me on this pile i guess, i just pulled the trigger on a vcu200 and it's sitting on my couch
Bisi of bisimoto made me do it, basically, his porsche K3v runs the vcu200

Although reading this thread gives me some pause, it sounds like I'll have to really architect the entire build around can communication between everything, which probably means making a lot of little CAN arduinos to take in can messages and spit out all kinds of signals to attached hardware
more i think on it, having everything on CAN doesn't sound so bad, converting from pwm to can will be the annoying part. i wonder if there are pe built arduinos with wifi chips for configuration or something built in
I don't think they have announced anything on that but I think its fair to say its in the works. I have no timeline or ETA.
So, does this board not work for the sport units?
and is the plan to have an entirely separate board for sport units, or will this board be usable with sport units, just needs a firmware flash to do so?
I was going by mojave's statement a bit back saying everything on CAN is easier, but i dont know if there are pins on the vcu200 for pwm fan control built in. If so that's pretty awesome and simplifies things
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.
See less See more
If you mean the vcu200/300 will work with the eluminator motor? I have no idea. From the people I talked to, they seem like decent folks so I'd be really surprised if they locked down support for such a popular motor.

If you shoot the tech team an email they'll probably give you some kind of alright answer
Edited my post, thanks for that correction Mojave

Not really sure as to the specific layout Floyd? I dropped aem tech an email asking for more specifics, this is kinda important for me since it may be more cost effective to get batteries with fewer cells
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.


See less See more
I'm 90% sure the AEM solution, whenever it happens, will be using their VCU and their bms-18 system, so it's all one big ecosystem

Also for my conversation I found a workaround of parellalizing cell taps across modules, so I can make 6 sets of three Pacifica modules but to the bms its still 96 cell, fitting neatly within the bms-18 108 max
I can't get AEM to reply via email or through their website. But they do answer the phone to answer technical questions.
Damn. That'd explain why I'm suddenly getting crickets asking about some can traffic issues I'm seeing
noticed this a while ago but aem has a nice pre-start checklist for the vcu, which might help some folks

got an email back about my canbus woes finally
apparently can2 is going to be reeeeeal quiet until i push the LDU firmware to the vcu200, a step i didnt realize existed, and put the cascadia LDU drive board in line with my benchtop setup and give it power etc

the email they respond on is [email protected] ?
Alright apparently I'm missing some crucial detail somehow but what procedure should I be following to load the necessary firmware for the drive unit control board? Does the firmware get loaded to the control board or to the VCU?

The documentation linked on this page
For the inverter control board

Mentions loading firmware to the board using the gui (although again, not sure if the VCU needs a firmware load too), and selecting G on the little switch thing for gui programming, but all that seems to require the board to be installed in a drive unit which I don't have yet. Without that, the big combined plug thing which came with the board won't work

Which begs the question, how can I power the drive unit control board on a bench? I want to get some traffic on can2 for some testing
i'd make a snide comment about windows issues but aemcal doesn't have a linux version so...
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

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
See less See more
1 - 15 of 82 Posts