Your battery voltage - truck off and at rest

[J Sierra]

The numbers look wrong to me looks like a data format problem. These numbers are the same past 3.5 and 3.0.
3.59999990463257
3.09999990463257

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[ShadowsPapa]

The numbers look wrong to me looks like a data format problem. These numbers are the same past 3.5 and 3.0.
3.59999990463257
3.09999990463257

I can't disagree with how it appears. The numbers look OK in the live display but leave question marks in my mind in their logs.

If you look at the raw numbers as it's being displayed, live in the app, it's correct, to the hundredths position.
I've used my Fluke, for example, to compare to what these apps display vs. what the cluster displays and so on - live it's fine. At least as far as voltages.
Either way, regardless of where things lie, anyone should for the sake of sanity ignore anything past 2 decimal places in this sort of thing.
I contacted JSCAN a while back about their log export format for other reasons besides this.

Even if you paid for the equipment to go out several places - IMO, for our purposes, it's just noise.

For comparison, this was a different Gladiator (my 2020) but this is how AlfaOBD exports the numbers -
Intelligent Battery Sensor Calculated Battery Resistance: 1.90 Ohm
Intelligent Battery Sensor Resistance at 100 % SOC and 25 Deg.C: 3.31 Ohm

So yeah, in the other posts anything beyond hundredths should be ignored as noise, data issues.
(it's a good call)

But the basic numbers do show that you aren't "pushing that many amps into the battery/batteries" at 14.9 volts because of resistances in the circuit - IBS and battery itself.

 

[J Sierra]

I bought a battery monitor $25 from Amazon. It gives battery voltage and temperature to your phone. Measures percent of charge, staring test, charging test, all while you drive. It gives a rolling graph for all the tests.

 

[ShadowsPapa]

I bought a battery monitor $25 from Amazon. It gives battery voltage and temperature to your phone. Measures percent of charge, staring test, charging test, all while you drive. It gives a rolling graph for all the tests.

And........ ?

Percent of charge is an estimate based on the battery voltage, temperature and other conditions (including battery type) so it's not likely to be totally accurate for $25 unless it's AGM specific and knows the battery like the IBS/PCM is programmed for.
So technically, you use your Off Road Pages or cluster and look at the voltage and can know the SoC as close as a $25 volt meter can.
Unless it also goes between the cable and the terminal, it can't do much more.

Starting test - can't do anything other than tell you the voltage as you crank it - and that doesn't mean a lot without knowing the starter draw (is the starter healthy, hot? cold?) battery health (the older a battery gets, the further the same starter draw will drop the battery voltage).
Charging test - it has no idea unless it's fit between the terminal and a cable and measures amperage. It would have to know resistance levels, and more to know how it's charging. A battery with high resistance will not take the same "amps" in at 15 volts as a different battery and temperature will matter.

I have voltage, temperature and more on my phone reading directly from the truck's computers via historical data in the BCM and PCM and the currents from the IBS.

Such a device is off the map as far as the purpose of this thread getting to the root of a few other things.

 

[Gatorized]

The numbers look wrong to me looks like a data format problem. These numbers are the same past 3.5 and 3.0.
3.59999990463257
3.09999990463257

I can't disagree with how it appears. The numbers look OK in the live display but leave question marks in my mind in their logs.

If you look at the raw numbers as it's being displayed, live in the app, it's correct, to the hundredths position.
I've used my Fluke, for example, to compare to what these apps display vs. what the cluster displays and so on - live it's fine. At least as far as voltages.
Either way, regardless of where things lie, anyone should for the sake of sanity ignore anything past 2 decimal places in this sort of thing.
I contacted JSCAN a while back about their log export format for other reasons besides this.

So yeah, in the other posts anything beyond hundredths should be ignored as noise, data issues.
(it's a good call)

I wonder if the additional digits are just log identifiers for each reading: resistance, current, voltage… in JScan.

 

[ShadowsPapa]

I wonder if the additional digits are just log identifiers for each reading: resistance, current, voltage… in JScan.

I've contacted the jscan folks to see what's up because the "logs" such as they are, are also filled with a lot of white space - in some cases dozens of blank lines between lines.

 

[J Sierra]

The meter does what you were doing with your Fluke meter. It can be programed from AGM. I also Have A 1000A shunt so I know how much current draw there is.

 

[ShadowsPapa]

Still not sure what your point is in this thread, though.
Many of us already have such devices - it's called a Bluetooth OBD adapter. And with free software, we can capture the data on our phones directly from the truck's systems. (and can chart it)

This is to determine other factors. (and it's gotten off track, of course)
So for a few bucks, one can gather all of this data with their phone - and use the adapter for changes to things like tire size and so on.

The problem with a shunt is that it's not going to be accurate since the batteries are connected in parallel so other than draw from a specific battery during an ESS stop event, it's not going to be accurate. You can measure what comes out of or goes into one battery (truck already does that) but can't account for what's coming out of the other.
The EHPS and cooling fans come directly from the crank battery while dash and cluster switches, HVAC, the ECUs (mostly) and so on come from the aux battery.
During an ESS stop I've read the voltages of each battery independently.

Anyway, this is supposed to be gathering info on voltages when shut down, a few hours later and so on.

 

[ShadowsPapa]

As I had hoped to do yesterday but life got in the way....... I went out and took readings of the truck at rest.
Drove 30 minutes, parked 45 minutes, drove 30 minutes back home and parked it at about 5:30 on Saturday so it had been sitting 36+ hours untouched.
No fob with me so as to not activate anything, didn't so much as touch a door so as to not awaken some of the electronics.
Voltage was 12.56
I opened the door and measured using my leads inside and just that action dropped the voltage 0.15 volts. I woke a sleeping giant.
Confirmed with readings directly from crank battery terminals - and it was 12.40 but slowly coming back up just a little bit.
Just opening a door wakes certain systems (the thing comes to life if you watch the dash as you open the door - even the passenger door)
I was pretty happy to see 12.56 volts after sitting for those hours.
I didn't bother to see if things were at 100% when I shut down on Saturday so it's possible things were not up to 12.7 or 12.8 when I parked it. Even if a measurement said it was that high - it can read high due to surface charge and only be 12.6 after draining off the surface charge.

 

[jebiruph]

And........ ?

Percent of charge is an estimate based on the battery voltage, temperature and other conditions (including battery type) so it's not likely to be totally accurate for $25 unless it's AGM specific and knows the battery like the IBS/PCM is programmed for.
So technically, you use your Off Road Pages or cluster and look at the voltage and can know the SoC as close as a $25 volt meter can.
Unless it also goes between the cable and the terminal, it can't do much more.

Starting test - can't do anything other than tell you the voltage as you crank it - and that doesn't mean a lot without knowing the starter draw (is the starter healthy, hot? cold?) battery health (the older a battery gets, the further the same starter draw will drop the battery voltage).
Charging test - it has no idea unless it's fit between the terminal and a cable and measures amperage. It would have to know resistance levels, and more to know how it's charging. A battery with high resistance will not take the same "amps" in at 15 volts as a different battery and temperature will matter.

I have voltage, temperature and more on my phone reading directly from the truck's computers via historical data in the BCM and PCM and the currents from the IBS.

Such a device is off the map as far as the purpose of this thread getting to the root of a few other things.

I'm not sure I agree with your assesment of the value of a Bluetooth battery testor for the purpose of this thread. If your goal is to test "Your battery voltage - truck off and at rest", then having the BT battery testor hooked up allows you to read the voltage without touching the truck.

While you can do the same thing with a Bluetooth OBD adapter, do we know if the BT OBD adapter is reading voltage directly or reading it from another module? If reading from another module, does having a BT OBD adaptor plugged in have any impact on the resting state of control modules it may communicate with?

As for the value of the BT battery tester's starting and charging tests, these tests aren't intended as battery tests, they are testing the external systems related to the battery, how low does the voltage drop when starting and how high does the voltage go when charging. One thing that the BT battery tester can do the the BT OBD adapter can't is test the aux battery.

 

[ShadowsPapa]

One thing that the BT battery tester can do the the BT OBD adapter can't is test the aux battery.

Can't actually test the battery, only measure the voltage unless that's what you meant - and at that, it can't do that unless the PCR is open. It's measuring the equalized voltage of both batteries.
Unless you trigger the PCR to open it, you can't get the voltage of the aux battery alone.
That's why I have a lead at N1 so I can read things during an ESS stop. Otherwise they are tied together. If such a device had two voltage inputs, that would be absolutely ideal.

While you can do the same thing with a Bluetooth OBD adapter, do we know if the BT OBD adapter is reading voltage directly or reading it from another module?

Would be dependent on the software used. There's 12v at the port.

I've got multiple software apps that read from the adapters, need to see where they are taking their information. (other than JSCAN, etc.)

I have an Amazon auto volt meter - it always reads lower than reality. I use it mostly when camping to watch for low voltage. Any future testing, methods, equipment, etc. will be higher end because we've seen how far off things can be - even two identical units can be different by tenths.

 

[J Sierra]

I have 2 one on the AUX, one on the main battery. They have rolling displays, as I drive the ESS event is captured. I can see the restart as a dip in the main battery voltage. I can see the AUX battery during the ESS event, goes down a bit. The rolling display goes as long as the phone is near the jeep, weeks in my case. I can see all the starts all the ESS events.

 

[ShadowsPapa]

I have 2 one on the AUX, one on the main battery. They have rolling displays, as I drive the ESS event is captured. I can see the restart as a dip in the main battery voltage. I can see the AUX battery during the ESS event, goes down a bit. The rolling display goes as long as the phone is near the jeep, weeks in my case. I can see all the starts all the ESS events.

That makes sense. You could chart BOTH batteries. However, will the app let you compare or display both, or is it a choose this device or choose that device and one at a time?
Can you export the "logs" - like maybe a comma delimited file for use in a spreadsheet and making charts?
I assume you are talking the Quicklynks (or however it's spelled, I know it's not like "links" - it's something else as I've seen them before.

Since you have two - have you observed the main battery AND aux battery both dropping by similar amounts during ESS events?

Call me dense here - I think I finally see where you are going.

What does it log - a week? 30 days? (without the phone - so if you left it sitting while you were elsewhere)

 

[J Sierra]

One at a time so on a long trip I used my wife's phone. This is what I found, the battery's never get fully charged 90 percent max. Going down hill for miles the battery voltage went up 0.2V. I think it is intentional not to charge the battery's all the way, to protect the battery's from over charge and to leave room for charge going down long hills. That sounds silly to me, might save gas. It will log 2 weeks I think. You can export the logs to a file of some sort I have not tried that. The current draw is 1.5 milli amps.

 

[ShadowsPapa]

One at a time so on a long trip I used my wife's phone. This is what I found, the battery's never get fully charged 90 percent max. Going down hill for miles the battery voltage went up 0.2V. I think it is intentional not to charge the battery's all the way, to protect the battery's from over charge and to leave room for charge going down long hills. That sounds silly to me, might save gas. It will log 2 weeks I think. You can export the logs to a file of some sort I have not tried that. The current draw is 1.5 milli amps.

LOL - I've wondered for a couple of years why they don't do something better about charging these.
I have noted on a HOT day, driving as far as a tank of gas will take me, interstate travel, about 80 mph, that the thing will cut voltage when the IBS says the battery is hot. (and in that case well charge, too). it will cut down to 12.6 - that's the lowest I've seen it.
Yes, I've watched on long drives when things are pretty well charged up that it varies voltage depending on the engine torque needed. Down hill, esp with any braking, it increases the voltage, back up a hill it drops again. Not a lot, but noticeable. (0.4 volts, for example)
I can't see why they'd not want the batteries fully charged - they monitor the temperature via the IBS and how much is going out vs going in.
I've noticed big differences between my 2020 and my 2022 as far as voltages. This 2022 voltage tracks a lot higher much of the time, but then I wasn't watching the 2020 as much when new - but never saw it over about 14.7. This one is routinely at 15.0 when it's really cold.

My other concern was anything on the batteries while it was at rest, stopped in my garage for 3 or so days, adding another parasitic draw. That's why I used the fluke (plus it's handy and I ran leads directly to the batteries - positive post of crank battery and N1 for aux battery - so I could switch the Fluke between batteries. Inconvenient, though.
My main motivation for this thread was to see if these ever fully charged on their own, and the results of them sitting, untouched, for 2, 3 or 4 days. I see numbers all over the place from others so obviously how they are driven, length of the drives (anything under 30 minutes isn't really doing anything for the batteries, they hardly come up at all) - information gathering.

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