Battery leakage detector (presumed)

[coulomb]

[ Edit: I neglected to mention that this detector resides inside the iMiEV battery enclosure. ]
I've seen this described as a "battery detector"; I'd say it's actually the battery leakage / insulation detector. Note the long plastic legs separating this device from the metalwork. (The mounting holes are cropped off in this photo, sorry).

Here is the PCB from above:

Two components stand out to me. The thing that looks like a battery (especially with code BAA3 on it), but it seems to be a zener diode, ZD8.

And this rectangular thing, that initially I thought was a PCB relay, is a capacitor, C13, 1 μF, presumably with a very high DC voltage rating. It connects from the double insulated orange cable to "earth" (the large area under the PCB, connects to what I assume is pin 1 of the 5-pin connector).

I count 6 8-pin chips, one (the smallest, marked LTTH e3) by Linear Technology, and three by Analog Devices (hence, quality and expensive). It seems like a lot of electronics just to measure insulation leakage. I'd love top know if this is way over-engineered, or just what it takes to make a reliable EV. [ Edit: the "e3" isn't a part number marking code, it's a code for the finishing of the leads. So that's no help. But see several posts down. ]

[ Edit: modified last paragraph to add "LTTH e3" and the mention of Analog Devices.
Changed subject insulation -> leakage. ]

 

[kiev]

Nice pictures of the Main Battery Ground Fault Detector. It has a pre-check/self-check feature so maybe that's the reason for so many chips.

Found this in the FSM:
The main battery ground fault detector is installed in the main battery. The main battery ground fault detector has the ground fault detection circuit. When a ground fault occurs in the high voltage circuit, the main battery ground fault detector should output the voltage into the BMU. This allows the BMU to detect the ground fault occurring in the high voltage circuit. The main battery ground fault detector has a pre-check circuit. When the pre-check signal is input from the BMU, the main battery ground fault detector should be quasi-state of detecting the ground fault. The BMU detects this signal to check that the main battery ground fault detector normally operates.

 

[kiev]

i can't find anything on the "LTTH" chip; all the others are dual op-amps (AD8617) and a dual comparator (2903Q1).

Is there anything of interest on the back side?

 

[coulomb]

Is there anything of interest on the back side?

No, no components, and only a handful of tracks.

 

[coulomb]

i can't find anything on the "LTTH" chip;

It seems to be a true RMS to DC converter. Why they want this I don't know. This definitely seems overkill to me.

Datasheet: https://datasheetspdf.com/pdf/635832/LinearTechnology/LTC1966/1

 

[kiev]

Thanks for finding the datasheet, i used up all my google-foo, even searching the LT site for part marking codes...

Well that is a very unusual datasheet. It would likely make more sense to know why this chip was needed if we knew how the rest of the board functioned. It appears that the entire board was designed around this chip based upon it's location in the center of the board and the fat silk screen borders.

 

[coulomb]

I believe that connector C-21, which connects to the battery leakage detector, is different between some models of iMiEV. C-21 looks the same in all the schematics that I've found (2011, 2012, and 2013), so I don't know any details. I wonder what might change that would require a different connector.

 

[nuggetgalore]

[ Edit: I neglected to mention that this detector resides inside the iMiEV battery enclosure. ]
I've seen this described as a "battery detector"; I'd say it's actually the battery leakage / insulation detector. Note the long plastic legs separating this device from the metalwork. (The mounting holes are cropped off in this photo, sorry).

Here is the PCB from above:

Two components stand out to me. The thing that looks like a battery (especially with code BAA3 on it), but it seems to be a zener diode, ZD8.

And this rectangular thing, that initially I thought was a PCB relay, is a capacitor, C13, 1 μF, presumably with a very high DC voltage rating. It connects from the double insulated orange cable to "earth" (the large area under the PCB, connects to what I assume is pin 1 of the 5-pin connector).

I count 6 8-pin chips, one (the smallest, marked LTTH e3) by Linear Technology, and three by Analog Devices (hence, quality and expensive). It seems like a lot of electronics just to measure insulation leakage. I'd love top know if this is way over-engineered, or just what it takes to make a reliable EV. [ Edit: the "e3" isn't a part number marking code, it's a code for the finishing of the leads. So that's no help. But see several posts down. ]

[ Edit: modified last paragraph to add "LTTH e3" and the mention of Analog Devices.
Changed subject insulation -> leakage. ]

Just a follow up on the leak detector ( presumed; but I am fairly confident it is, the only PCB I find in the battery enclosure apart from the ones on the modules).
Like so many other parts on my 2010 model, this too is different from what later iMiEVs have.
For a start, the PCB appears to be upside down, compared to the one you photographed.

here is the PCB from above

I can see some similarities but more differences.
I wonder if they would be compatible? the 5 pin connector looks similar.

Google/wikipedia have nothing on this part no.
I had a close look at all the components ,no obvious breaks or burn marks. If it is faulty I certainly would not be able to test it.