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Post by stoffl on May 12, 2020 15:40:06 GMT
Hello, my OBDeleven pro says voltage is 11.5 V or 11.6 V on ist main page (yellow battery symbol), when I measure it on the battery terminals it is close to 13 Volts. But when I try to change i in settings/calibrate voltage it says calibration done, but there is no change on the intro page, still yellow Symbol and 11.5 V displayed. Has someone changed this successfully? Thanks in advance
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Post by reppad on May 29, 2020 10:29:35 GMT
Hello, I have the same behavior. The main screen displays a voltage under 12V but when I measure it or display the voltage in live datas the value is over 12V. The application displays green confirmation message when I use the voltage calibration feature (no error) but the value does not change in the main screen. I tried with the real voltage value and some false value just to see if the calibration has an effect on the value displayed and I can't see any effect. This behavior appear only with my next gen device, when I try the same thing with my old gen device (same phone, same car), the voltage calibration has an effet on the vaue displayed on te main screen. stoffl you use a next gen device (black dongle) or a old gen device (white dongle) ?
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Post by aleone1994 on Apr 16, 2021 8:26:41 GMT
Hi. I have a similar issue. I charged my seat ibiza kj battery and with the multimeter I read 12.47V but when I attach obd eleven I read 12.12V in live data and 12.0V in the home screen next the battery symbol...how is thst possibile? Pla help
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Post by doc0427 on Apr 16, 2021 12:33:12 GMT
I also have this same issue... about 0.2-0.4V lower than what it should be. I’m using the 2nd gen (black) device with an iPhone.
By the way, where is this “calibration “ function located? I have not seen this in the app?
Cheers... DoC
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Post by doc0427 on Apr 16, 2021 16:59:19 GMT
This makes sense because 12.47v is measured with the multimeter, the 12.12v is what the car’s computer is measuring and you are just viewing that measurement in the live data. The 12.0v is what the OBDeleven is measuring itself.
There are expected differences in readings from different measuring devices and measuring at different parts of the circuit may measure different values. The detected value at the OBD connector should be very close to the value right at the battery since its usually a direct connection.
Clearly, like the rest of us on this thread you too have an OBDeleven device that does not measure the battery voltage correctly.
Again, live data is just viewed value from somewhere, not a measured value by the OBDeleven.
Cheers... DoC
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Post by dv52 (Australia) on Apr 16, 2021 19:34:32 GMT
hmmm........... without intending any offense to the thoughts that have been espoused above - there might be a number of electrical concepts being confused here. First, I learned long ago (as a very young and naive engineering student) that simply because a meter reads a certain number - doesn't mean that it's correct (meters do lie - often)! At the heart of the differences between voltage readings taken by different devices at different points on the car's electrical system is the dreaded "VD". Not the VD that you are probably thinking about - this VD stands for Volt Drop and it happens because of the famous Ohm's law.
It's convenient to consider a vehicle's voltage rail as a single power source that has the same electrical potential as the battery, and as a first approximation, this is true. However where we start comparing vehicle voltage measurements to the decimal point, VD starts to become important, as does the accuracy of the meter.
The reality is that a car has a continuously variable voltage rail depending on how and where the reading is taken - and depending on what method is used to take the measurement. I suspect that's why OBD11 allows the reading on the main screen to be adjusted!
Don
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Post by doc0427 on Apr 16, 2021 21:17:04 GMT
I agree entirely Don, no offence taken!
My experience has been that indeed meters do “lie” but they are generally pretty accurate to the tenth of a volt (0.1) when measuring potential. Nevertheless what the OP started with was the reading on the front page of the OBDeleven app, which is basically what the OBDeleven device itself is measuring on the OBD connector.
At that point, it’s most definitely measuring low. I have put 2 different Fluke DMMs on the back of the connector while the OBDeleven is connected, and the 2 DMMs read the same, the OBDeleven reads consistently 0.4V lower at both when the engine is running or not. Looks like a calibration issue but...
1) I don’t see any calibration function on my iPhone app version. 2) users above report the calibration function has no effect anyway.
The good thing is that this is nothing more than a minor annoyance, for me anyway.
Cheers, DoC
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Post by dv52 (Australia) on Apr 16, 2021 22:04:01 GMT
DoC: The crucial question is what exactly is OBD11 measuring - and is it useful? As you already know, the OBD port has its own T30 Voltage which is invariably fused (so already some in-line resistance) and this fuse is always shared with other equipment.
Ain't nothing remarkable about measuring a VD on a pin on a downstream connector. A delta of 0.4V doesn't sound too bad - particularly since I doubt that you were able to make really firm contact with the pin and the earth connection was likely remote from the battery negative terminal.
I'm not sure what voltage the OBD11 dongle measures - it could be volts on the T30 pin on the OBD port, or it could be the CAN network voltage or it could be any number of other voltages.
To be frank (or, I can be earnest if you want ), I never-ever take ANY notice of this voltage - it's palpable nonsense IMO. If I have concerns about battery voltage, I will measure true battery volts. Or if there is a problem with the downstream voltage rail and the VD is material, I expect CAN error messages telling me just that.
My suggestion (again, no offense intended) - put your Fluke MMs to better use. Life's too short!!
Don
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Post by aleone1994 on Apr 18, 2021 6:11:56 GMT
This makes sense because 12.47v is measured with the multimeter, the 12.12v is what the car’s computer is measuring and you are just viewing that measurement in the live data. The 12.0v is what the OBDeleven is measuring itself. There are expected differences in readings from different measuring devices and measuring at different parts of the circuit may measure different values. The detected value at the OBD connector should be very close to the value right at the battery since its usually a direct connection. Clearly, like the rest of us on this thread you too have an OBDeleven device that does not measure the battery voltage correctly. Again, live data is just viewed value from somewhere, not a measured value by the OBDeleven. Cheers... DoC Thanks a lot. However my battery is still good after 3 years of life. I never had battery problems even when I start the car..i was having this doubt during a voltage drop while I was making the backup of a centraline (but it's normal). So thank you for your answer!
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Post by aleone1994 on Apr 18, 2021 6:21:22 GMT
DoC: The crucial question is what exactly is OBD11 measuring - and is it useful? As you already know, the OBD port has its own T30 Voltage which is invariably fused (so already some in-line resistance) and this fuse is always shared with other equipment.
Ain't nothing remarkable about measuring a VD on a pin on a downstream connector. A delta of 0.4V doesn't sound too bad - particularly since I doubt that you were able to make really firm contact with the pin and the earth connection was likely remote from the battery negative terminal.
I'm not sure what voltage the OBD11 dongle measures - it could be volts on the T30 pin on the OBD port, or it could be the CAN network voltage or it could be any number of other voltages.
To be frank (or, I can be earnest if you want ), I never-ever take ANY notice of this voltage - it's palpable nonsense IMO. If I have concerns about battery voltage, I will measure true battery volts. Or if there is a problem with the downstream voltage rail and the VD is material, I expect CAN error messages telling me just that.
My suggestion (again, no offense intended) - put your Fluke MMs to better use. Life's too short!!
Don
Thank you too mod! So I learned that the better thing is measure the value directly from the battery. However I used a ctek mxs 5.0 to recond my 3 year battery becouse it was on 12.10V (measured directly with a tester). After that, now, the voltage in rest state is 12.30V. I think that my battery is still in good state. I'm thinking to use recond mode another time the next month
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tt225
New Member
Posts: 2
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Post by tt225 on Jun 14, 2021 10:50:05 GMT
I'm so glad I found this thread because I started to worry that my battery was dying. Good to see that the 11.5v (and yellow battery icon) is either an app glitch or the OBD port gives a voltage drop reading - either way, my battery is fine and that's good.
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