pipa92
Junior Member
Posts: 73
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Post by pipa92 on Nov 19, 2022 15:44:08 GMT
Is there a way to use OBDEleven to read and or measure car battery health on AUDI cars?
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Post by dv52 (Australia) on Nov 20, 2022 22:14:56 GMT
pipa92: Hi - and thanks for an excellent question!!
Your question is very broad and of course the answer depends on what you mean by "battery health". It also depends on the model Audi and on the equipment that was factory fitted to the car to measure battery health- like the Battery Monitor control module (it's called "J367" in the wiring diagram) - not ALL Audi's have this module. Anyhow, as an example of what's possible - for Audi's that have a MQB platform build - the car's Energy Management System (EMS) is controlled by the module that OBD11 calls the Gateway Module - which lives @ address hex19 on the CAN network. All Audi's have a EMS - but the particular form of EMS that's used is not the same across all models, nor is the EMS is the same across all cars within a model.
Of course, battery condition is a major component of interest for the car's EMS - so this module records many aspects about battery health which it then uses to calculate variables like charging profile for the Alternator. The variables that are recorded by the EMS are accessible to users via any diagnostic device such as OBD11.
The access procedure for this information is like this: - With both ignition-only and for engine running (you should use both conditions) - plug-in the OBD11 dongle into the car's OBD port and connect to the OBD11 software.
- Navigate to the Control Module screen and select Gateway Module
- Scroll-down to Live data
- In the search box - enter "Battery", then click on Select all
- The following screen should appear:
- click on Done and you should get the current readings
That's it!!!
Don
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Post by sleepyhd on Dec 17, 2023 15:50:40 GMT
the car's Energy Management System (EMS) is controlled by the module that OBD11 calls the Gateway Module - which lives @ address hex19 on the CAN network. All Audi's have a EMS - but the particular form of EMS that's used is not the same across all models, nor is the EMS is the same across all cars within a model.
Of course, battery condition is a major component of interest for the car's EMS - so this module records many aspects about battery health which it then uses to calculate variables like charging profile for the Alternator.
This is my first post so hello everyone... Is there any way to modify this Energy Management System, charging profile or maximum SOC level (by coding or hardware trick)? In my car (Skoda Fabia IV) the soc is probably set to 78%. Once this level is reached, the current to the battery is only about +0.1 amps. I have never seen a soc higher than 78%. After a few days of not using the car, it is only 53% I don't drive my car every day and only for short distances around the city, so it would be nice to set the maximum soc level to, for example, 90-95%. I was thinking of entering a higher false capacity than the car battery actually has, so that 78% of the false capacity would equal 90% of the true capacity. Would that work? |
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Post by dv52 (Australia) on Dec 17, 2023 20:33:49 GMT
sleepyhd : Hi. Hmm......... I don't think that "telling-porkies" to the Gateway module by increasing the the value of the battery capacity is a good thing because it impacts a fundamental aspect of the battery's charging profile - but I'm not sure! You haven't said - but I assume that this car has Start Stop (SS). A SOC level of about 80% is quite normal on ALL MQB platform cars like your Skoda Fabia IV that are factory fitted with SS. Therefore, I don't think that low kms traveled is a problem on this car!
The reason why the EMS does NOT completely fill the SOC to 100% is because cars fitted with SS have regenerative braking. This is a system where whenever the driver presses the brake, the voltage limit on the alternator is increased whist the car's momentum is decreasing. This causes the alternator to inject more electrical current into the battery without using any additional fuel Regenerative braking effectively converts the car's kinetic energy into electrical energy.
So, for regenerative braking to work - the designers of the car's EMS need to make sure that a proportion of the total battery capacity is available to receive the extra energy generated. This is the reason why maximum SOC on cars with SS is about 80%! It's because the remaining 20% SOC is the battery headroom that is devoted to receiving energy from the regenerative braking function!!
And the short answer about hacking the SOC level is NO, alas (at least AFAIK). I don't believe that there are many aspects of the car's EMS that are accessible to third party diagnostic devices like OBD11 - happy to be informed otherwise!!
As for your issue with low battery SOC resulting from low Kms traveled (again, a SOC of about 80% is entirely normal) - the way to manage this is with a trickle charger. I've installed many of these on cars that routinely drive low kms. My solution is to make a small wiring loom from the battery terminals (with an in-line fuse) to the front grille with a weatherproof connector that's accessible without the need to lift the bonnet. This makes it easy for the driver to connect the trickle charger whenever the car is garaged. With an appropriate plug/socket and with the correct orientation of the trickle charger connection wrt the front grill - it's also possible for the connection to be safely pulled-apart if the driver forgets to disconnect the charger before driving out of the garage (which has happened with some of my installations!).
Don
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Post by sleepyhd on Dec 18, 2023 8:35:00 GMT
Thanks dv52 for the comprehensive explanations. And for destroying my dreams  Yes, I have SS. And I never use it. An SS with a three-cylinder engine without a balance shaft is a nightmare. It's worse than grandpa's old diesel truck. I understand the need to provide additional space for recovered energy. But in the good old days it was always said that a car battery dies faster if it is not always charged to 95-100%. I have a car battery charger (Osram 6A) but I no longer have a wall socket in the underground garage (thanks to stupid plug-in car owners) So, I have to make sure that the current consumption is as low as possible when parked. When I turned off Skoda Connect, the current consumption dropped from 80 mA to 28 mA, which is within the VW standard according to the bulletin. But in the old "not so smart" car I had less than 10mA. So now the car alarm is up for investigation. But it's connected to a remote lock. Ah, I miss the old days when cars were stupid and fuel was cheap... |
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Post by dv52 (Australia) on Dec 18, 2023 20:49:27 GMT
Thanks dv52 for the comprehensive explanations. And for destroying my dreams I'm always devastated when I destroy dreams (because they are fantastic objectives). In this case however, I respectfully suggest that this particular dream might not be so important  !! Yes, I have SS. And I never use it. An SS with a three-cylinder engine without a balance shaft is a nightmare. It's worse than grandpa's old diesel truck. I understand the need to provide additional space for recovered energy. But in the good old days it was always said that a car battery dies faster if it is not always charged to 95-100%. hmm...........yes, I think that you are referring to the "good old days" when bog-standard "wet-cell" type batteries were all the rage!! On cars that are factory fitted with SS, the installed battery uses either Absorbent Glass Mat (AGM), or Enhanced flooded Battery (EFB) technology - very different operating characteristics!!
I have a car battery charger (Osram 6A) but I no longer have a wall socket in the underground garage (thanks to stupid plug-in car owners) So, I have to make sure that the current consumption is as low as possible when parked. When I turned off Skoda Connect, the current consumption dropped from 80 mA to 28 mA, which is within the VW standard according to the bulletin. But in the old "not so smart" car I had less than 10mA. So now the car alarm is up for investigation. But it's connected to a remote lock. Ah, I miss the old days when cars were stupid and fuel was cheap... Yes indeed, the electrical current-draw for the sleep-state on MQB platform cars is a tad higher than "not so smart" cars and I too miss the simplicity of cars in the old days! But, the sheer beauty of the technology in modern cars more than compensates for my nostalgia!! 
I suspect that your continued efforts to find more savings might be a case of diminishing returns!! If this car stays unused in the underground car park for an entire week and with your current sleep-state battery drain of 28 mA - the total battery load will be: - 0.028 amperes x 24 hrs x 7 days = 4.7 Amphours/week
Not too shabby!!! |
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