Wednesday, July 15, 2015

HDS Consumption Current History

I'm starting set of posts about what you can do with HDS.

First will be Consumption Current History.
This option you have on new cars.

Why should you care about consumption history?
This information is measured periodically by ECU when ignition is off.

Theory of operation (skip if not interested).
On Honda, we got Bosch EBS sensor (part-num 38920-TR0-A01) on negative terminal of the battery.
One method of reliably determining the battery charge level is provided by the Bosch Electronic Battery Sensor (EBS), a key component of the energy management system. Installed in the battery pole niche, it dynamically records the battery parameters of current, voltage and temperature with the utmost precision. The battery status recognition software integrated in the EBS uses these readings to determine the current and anticipated future status of the battery. In addition, the EBS offers advanced diagnostic functions during production, vehicle transportation and service operations. - from here

X-ray view of similar to Bosch sensor from Freescale (from here)
Interesting quotes from Freescale specs:
- Measurement range up to +/-2000A with an accuracy of 5 mA and a resolution of 1 mA
- Temperature  Accuracy: +/-2°C (-20 to 60°C) and +/-3°C (-40 to 125°C)

This is how it looks on my car.
Sensor 38920-TR0-A016-M1, made in Hungary.
HW (hardware = board and components) version 06.02, SW (software) version 03.01.
Also, you can see production date on it 2013-02-04.

End of theory.
More theory in austriamicrosystems Automotive Battery Management (PDF).

Say you have dashcam that works when engine is off. Should it drain your battery too much? You can end up in situation when you need to jump-start your car or even replace a battery if you not checked this things before (better) or after installation. Or you have other electronics connected.

Of course, you can do checks with DMM but now we have all data in ECU and it's more cool because it checks few times.

So, opening HDS

This is how my Civic is detected.

Main menu. Choosing Consumption Current History.

Little note what is about. Press Yes!

Next slide is first period.
When I turned ignition off, consumption was about 430 mA.
1 hour later that is my dashcam + security code staff + Honda's cunsumption.
2 hours - the same.
11 hours later my dashcam was switched off because I got a controller that monitors battery voltage and if it drops below setting (12V) it shuts off load - dashcam.
So 70 mA is car stuff. Not good actually, it shoul be around 20-40 mA. Need to check it.

Looks like it measures first 2 hours intervals and last one just before start, probably, when you inserted the key or opened the car.

UPDATE (2016-04-30)
Snapshot from manual mk9 Civic with original Israel's pass key secure and Blaupunkt New York 830.
Looks almost good. I would expect it to be around 30 mA. Probably local installs added ~20 mA.

Bonus slide.
That is which modules you can access with HDS. Most of them available, but not all.
PGM FI - is Engine Control Unit (ECU), AT - transmission, SRS - airbags, and so on.. Stay tuned! ;-)

32,841 km | 2Y 1M