Battery ECU secrets and teardown (warning: geek content)

ericbecky · Apr 29, 2018

I would really like a few of those connectors.
I have an idea for some projects
Care to contact me directly with the info? Pm, call, text, or email.

Rossini2 · Feb 1, 2020

pEEf said: ↑

I'm presently working on an outright replacement for Toyota's Battery ECU for my PHEV project. I'm sure others are also curious, so here's my initial teardown and analysis of the hardware:

The ECU sits on the end of the CAN bus, so it has a 120 ohm termination resistor. (on bottom of board) The Battery ECU has no other communication systems.

The Battery ECU monitors the Traction battery main voltage along with 13 tap points spread evenly along the pack. This is done to detect pack balance. Battery Current in/out is also sampled using a hall-effect current sensor, and this signal comes on on pin C-15. This is used internally for "coulomb counting" to keep track of battery state-of-charge (SOC). There are 4 Battery temperature probes that use temperature-dependent resistors, and finally the battery fan voltage is sampled.

The ECU also controls the Battery Fan Relay, and outputs a PWM signal to that is used by the fan motor controller to adjust the speed. There are no other control outputs used, but of interest is an additional 1A output that sits unused. (pin A-11) There are also several additional inputs that are also not used in this application.

They use little optically-coupled solid state relays to select which of the 14 battery voltage taps they wish to read, and then use another pair as a switched-capacitor sample system to preserve electrical isolation. It's interesting to note that this board was designed to support 6 additional voltage monitor taps. (components not populated however)

Note that the Battery ECU does not control precharge or the main battery relays, that is done by the Hybrid ECU.

There is a 4K non-volatile EEPROM on this board, and in addition the microcontroller memory remains powered up at all times unless the +12v battery is disconnected. It doesn't seem as though SOC is stored in the EEPROM, as it seems to go to an arbitrary value if +12v is lost. This then begs the question as to what is being stored in there?

I have not yet determined the microcontroller used, as it has house markings. It's similar to models offered by Fujitsu, so this is a possibility. I am not sure if it contains a masked ROM or flash, but there is a high probability it's Masked ROM. I will need to decap the part to inspect the silicon directly if we are to learn more.

FYI: You may repost this picture and text only if credit is properly given.
Click to expand...

Brother my Ecu is showing have one pic broken whta should I do buy new one or do something els

Rossini2 · Feb 1, 2020

Hybrid Battery Exchange said: ↑

Got my hands on a sample batch of these connectors and replaced it on a battery computer that was working fine but had corrosion on the pins, will finish a few more a test them each out for a few months to see how they hold up. I touched up a few solder joints after taking the picture (for the eagle eyed).
Click to expand...

From where did you got new conector I have same problem

bisco · Feb 1, 2020

a company in china

ericbecky · Feb 2, 2020

Get a used one from online or a local scrap yard.

edthefox5 · Feb 3, 2020

Bummer I thought pEEF was back with some interesting stuff.

Rossini2 · Feb 5, 2020

ericbecky said: ↑

Get a used one from online or a local scrap yard.
Click to expand...

Thanks I fixed it but now new problem my car doing some noice not too much but it show p0303 code what will the problem

bisco · Feb 5, 2020

Can u post a recording of the noice?

ericbecky · Feb 5, 2020

P0303 is an engine misfire.
You'll have to start tracking things down up there now .

lunacyworks · Sep 29, 2020

pEEf said: ↑

I'm presently working on an outright replacement for Toyota's Battery ECU for my PHEV project. I'm sure others are also curious, so here's my initial teardown and analysis of the hardware:

The ECU sits on the end of the CAN bus, so it has a 120 ohm termination resistor. (on bottom of board) The Battery ECU has no other communication systems.

The Battery ECU monitors the Traction battery main voltage along with 13 tap points spread evenly along the pack. This is done to detect pack balance. Battery Current in/out is also sampled using a hall-effect current sensor, and this signal comes on on pin C-15. This is used internally for "coulomb counting" to keep track of battery state-of-charge (SOC). There are 4 Battery temperature probes that use temperature-dependent resistors, and finally the battery fan voltage is sampled.

The ECU also controls the Battery Fan Relay, and outputs a PWM signal to that is used by the fan motor controller to adjust the speed. There are no other control outputs used, but of interest is an additional 1A output that sits unused. (pin A-11) There are also several additional inputs that are also not used in this application.

They use little optically-coupled solid state relays to select which of the 14 battery voltage taps they wish to read, and then use another pair as a switched-capacitor sample system to preserve electrical isolation. It's interesting to note that this board was designed to support 6 additional voltage monitor taps. (components not populated however)

Note that the Battery ECU does not control precharge or the main battery relays, that is done by the Hybrid ECU.

There is a 4K non-volatile EEPROM on this board, and in addition the microcontroller memory remains powered up at all times unless the +12v battery is disconnected. It doesn't seem as though SOC is stored in the EEPROM, as it seems to go to an arbitrary value if +12v is lost. This then begs the question as to what is being stored in there?

I have not yet determined the microcontroller used, as it has house markings. It's similar to models offered by Fujitsu, so this is a possibility. I am not sure if it contains a masked ROM or flash, but there is a high probability it's Masked ROM. I will need to decap the part to inspect the silicon directly if we are to learn more.

FYI: You may repost this picture and text only if credit is properly given.
Click to expand...

Anyone have this for Gen 3 [89892-47020]?

Battery ECU secrets and teardown (warning: geek content)

ericbecky Hybrid Battery Hero

Rossini2 New Member

Attached Files:

image.jpg

image.jpg

Rossini2 New Member

bisco cookie crumbler

ericbecky Hybrid Battery Hero

edthefox5 Senior Member

Rossini2 New Member

bisco cookie crumbler

ericbecky Hybrid Battery Hero

lunacyworks Member

About PriusChat

Quick Navigation

Like us on Facebook

Buy us a beer!

Useful Searches

Battery ECU secrets and teardown (warning: geek content)

ericbecky Hybrid Battery Hero

Rossini2 New Member

Attached Files:

image.jpg

image.jpg

Rossini2 New Member

bisco cookie crumbler

ericbecky Hybrid Battery Hero

edthefox5 Senior Member

Rossini2 New Member

bisco cookie crumbler

ericbecky Hybrid Battery Hero

lunacyworks Member