Dimensions
- Width:
- Length:
- Height:
- Mass: 13kg
Separating the case
To fit the EVBMW control board you will need to separate the casing of the inverter.
- Put the inverter with the (usually black) stamped steel cover down.
- Undo the M6 bolts (10mm hex head) around the L-shaped plate on the top.
- Remove the shiny bolts (also M6/10mm hex) below that retain the high voltage connectors. Note: you will need to remove all of these bolts, even if there are no connectors attached as otherwise you will pull out some of the captive nuts when you withdraw the top half of the inverter
- Pull out any high voltage connectors.
- Next, remove the next ring of bolts positioned about a quarter of the way up the inverter body
- Remove the two oval black plastic covers on the sides of the inverter. Slowly lever them out with a small screwdriver, getting under the lowest face of the cover. The covers will snap into two pieces if you lever on the protruding parts. They can be easily glued back together but this can be avoided.
- Undo and remove the bolts behind each of the plastic covers.
- Now you can crack the case. Remember: cast aluminium cracks pretty easily so you don’t want to be hammering on it if you can avoid it.
- Insert a flat blade into the crack between the two halves of the case and run it around to cut the sealant.
- Gently lever the two halves apart until you can insert a screwdriver or similar. Avoid levering on any protruding parts of the case as these may snap off. Stick to the main body.
- Once you can open up some distance, move slowly as the sealant will take time to part. Run the knife around again carefully.
- Work your way around the case slowly until it comes apart. Try not to put any pressure on thin parts of the casing. Eventually it will separate.
- Lift away the top part and put it to one side.
EVBMW Prius Gen3 Control Board
Read the wiki here before beginning.
Control of the Prius Gen 3 inverter can be captured by the replacement of its main logic board with one from EVBMW. Note: this approach is being phased out in favour of serial or CANbus control of inverters.
Fitting the EVBMW Board
- Inside the inverter you will see two logic boards, one on top of the other.
- The one you will be replacing is the top one so go around undoing all of the connections on it, making sure to find the unlocking tabs on each. They can be a little fiddly but they will come.
- Particularly challenging is the 50 pin connector in the centre. This is best removed by very gentle levering of the sides while pinching the locking clips.
- In order to remove the board you will need to remove the white plastic frame that holds various sensors and connections. Undo the hex head bolts around the base.
- Then undo the screws holding this board in and remove it.
- Replace the board with your open inverter board
- Reconnect all of the sensors
- Follow the voltage testing procedure on the open inverter wiki here.
- Once you are confident the board is working properly, reassemble the inverter
Tweaking the DC-DC Converter
By default the DC-DC converter in the Prius Gen 3 Inverter will shut down at something over 200 volts. If you want to run the DC-DC converter at something over this, you will need to change some of the resistors on the logic board that is found under the black steel plate on the opposite side of the inverter to the primary logic board.
Removal is very much the same as for the top half of the casing: undo the bolts then slowly and carefully cut through the sealant goop and lever the cover up.
Follow the instructions here: https://youtu.be/Nu5_OBOPk4s. The resistors you need to replace are all 120kohm – you will need eight 210kohm surface mount resistors (1%, 0.5W, 0805, Manufacturer part#: ERJP06F2103V Farnell #: 2326773 ). On the top side of the control board these are numbered R629, R627, R625, R623 and on the bottom side, R630, R628, R626, R624.
High Voltage Connections
Battery Terminals
The battery connections for the modified inverter are now made at behind one of the plastic plugs you removed in disassembly. Check the wiki for details or see this video for more information: https://youtu.be/ECTBuC8i7Yg. Check the STL file library below for shrouds for these connections.
Motor Connections
The motor is typically driven by the MG2 side of the inverter. This is the three phase connections on the left hand side of the inverter as you look at the face where the high voltage connections enter.
It is also possible to bridge MG1 and MG2 for greater output. See the wiki for more information.
Ancillary Connections
The original connection points for the battery and air conditioning system on the Prius – behind the two round ports on the face of the inverter – provide space for connecting a charger, heater, or other ancillary. The positive connection is the one that is fused on the side port. The negative is common between the two ancillary ports.
In order to use these ancillary ports, OR the DC-DC converter, you will need to bridge the positive battery terminal with the third terminal in the same location. Again, see the wiki for more information.
Low Voltage Connections
You can connect to the 34-way IDC directly on the EVBMW board or use a daughter board from EVBMW to translate these connections into an automotive standard AMPSeal connector via a short IDC cable and daughterboard.
Sealing the Inverter
You can find a library of 3D printable blanking plates, shrouds and mountings for the AMPSeal and high voltage connections here.
