A few months ago, there was an Insight engine (including IMA etc) on ebay. Matt Muelver, who is on the yahoo group, bought it.
He sold me the BCM last week (the box that monitors battery sub-module voltages and temperatures). I posted a picture here:
http://homepage.mac.com/kusig/PhotoAlbum2.html
The one thing that seems pretty obvious from looking at it: there is no active charge equalization. This surprises me somewhat. I still don't understand how they keep the cells from building up major differences over time.
The ten green single inline modules you see along the top are connected to the module voltages. Apparently, they provide galvanic isolation for each voltage input. On the other side of the isolation barrier, they have a power supply bus (6 lines, for some strange reason!), a signal bus (two lines) and one line each going to the micro.
My going theory is that each SIM has an A/D converter on the battery side of the isolation and optocouplers for the digital signals (probably an SPI or similar serial bus). This would make a lot of sense and explain the two bus lines common to all SIMs and the one chip select unique for each module. The overall size of the SIMs and the tiny traces going to the battery all indicate that there is no power supply for charge equalisation.
Some other facts: The micro is a Hitachi H8. The frame is ultra-light magnesium alloy (Honda crazyness!). The rest of the circuitry is pretty much temperature measurement, two-speed fan control, serial bus to MCM and a bunch of power supplies for different isolated circuits.
He sold me the BCM last week (the box that monitors battery sub-module voltages and temperatures). I posted a picture here:
http://homepage.mac.com/kusig/PhotoAlbum2.html
The one thing that seems pretty obvious from looking at it: there is no active charge equalization. This surprises me somewhat. I still don't understand how they keep the cells from building up major differences over time.
The ten green single inline modules you see along the top are connected to the module voltages. Apparently, they provide galvanic isolation for each voltage input. On the other side of the isolation barrier, they have a power supply bus (6 lines, for some strange reason!), a signal bus (two lines) and one line each going to the micro.
My going theory is that each SIM has an A/D converter on the battery side of the isolation and optocouplers for the digital signals (probably an SPI or similar serial bus). This would make a lot of sense and explain the two bus lines common to all SIMs and the one chip select unique for each module. The overall size of the SIMs and the tiny traces going to the battery all indicate that there is no power supply for charge equalisation.
Some other facts: The micro is a Hitachi H8. The frame is ultra-light magnesium alloy (Honda crazyness!). The rest of the circuitry is pretty much temperature measurement, two-speed fan control, serial bus to MCM and a bunch of power supplies for different isolated circuits.