More battery pack data - GreenHybrid - Hybrid Cars


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Old 10-18-2017, 10:51 PM
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Default More battery pack data

I collected some OBD data today from a short (roughly 3 minute) drive of my 2010 Escalade Hybrid including a bit of WOT and some hard braking. SOC varied from 44 to 48% during the drive.

The data doesn't look great to me. Here's a summary:
Highest voltage of any cell pair: 18.1 V
Lowest voltage of any cell pair: 12.1 V
Largest instantaneous delta between lowest and highest cell pair: 4.3 V
Largest delta between lowest and highest voltage of a single cell pair: 5.7 V

A chart of the cell pair voltages is attached. I would appreciate any feedback about what this says about the condition of the battery.
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More battery pack data-battery-voltages.png  
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Old 10-18-2017, 11:08 PM
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Default Re: More battery pack data

Absolutely atrocious; however, I expect it's likely a function of the data collection. I suspect that you're gathering data very slowly, which can introduce huge errors.

I have found that 2 readings per second gives reasonably good results.
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Old 10-19-2017, 06:48 AM
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Default Re: More battery pack data

Yes, for sure there are some slow reads. I was logging data every 500 ms to make sure I did not miss any readings. However, all that means is that the various batteries aren't all read simultaneously. Any time you see a flat section in the graphline it means there was no new data for that battery. Having said that, the data collected was real. There definitely is a cell (#6 in this case) that reached 17.8 V when charging and 12.1 V when discharging.

To get faster data I will try reading fewer batteries at a time. I'll pick a couple of the cells that seem to be the worst and graph them next.
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Old 10-19-2017, 07:33 AM
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Default Re: More battery pack data

Without the ability to compare block voltages at nearly the same moment in time, this exercise won't get you anything. BTW, you are not reading cells. You are reading blocks - groups of 12 cells. You need to take single point data within about 25ms.
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Old 12-05-2017, 02:54 PM
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Default Re: More battery pack data

I know this is an old thread but I am trying to find someone that has detailed information on the GM 2 mode hybrid system. I have a 2013 Yukon Denali hybrid with an OBD2 reader using Torque Pro. I am using the custom CSV file found on this forum. My specific issue is with how much state of charge percentage maximum with engine running. I drive with Uber and Lyft and sometimes sit a lot or drive around town all night less than 35 miles per hour. While sitting the engine starts at 42 percent SOC. The engine shuts off at 47% SOC. Is this normal because it really doesn't do me any good when I can't stay on battery because I never reach 60% SOC. Is this adjustable or if I replace the cables on the alternator will that improve how much contribution the engine provides to the battery charge.
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Old 12-05-2017, 03:34 PM
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Default Re: More battery pack data

Are you serious?
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Old 12-05-2017, 07:04 PM
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Default Re: More battery pack data

Quote:
Originally Posted by S Keith View Post
Are you serious?
Are you referring to my post? Yes I'm serious. It makes no sense to me that when engine is running that it doesn't top off the hybrid battery. Even when at highway speeds it doesn't get past 50%. I know there is some concern about leaving enough room for regenerative braking, but come on we don't get over 62% as it is. Why not top off to that point with any charging cycle?
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Old 12-05-2017, 07:14 PM
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Default Re: More battery pack data

You were talking about an alternator on a hybrid... bigger cables and somehow implying that a 14.4V alternator, if present, would have some function in charging a battery that readily attains 330V+

I didn't see how you could be serious.

You clearly don't even have a basic understanding of your vehicle. I recommend you do a little research before pretending you know better.

Since most of your post doesn't make much sense, I'll just focus on the one question you asked:

Because it's not a good idea. It's wasteful (not fuel efficient), and it damages the battery.
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Old 12-06-2017, 10:49 AM
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Default Re: More battery pack data

Quote:
Originally Posted by S Keith View Post
You were talking about an alternator on a hybrid... bigger cables and somehow implying that a 14.4V alternator, if present, would have some function in charging a battery that readily attains 330V+

I didn't see how you could be serious.

You clearly don't even have a basic understanding of your vehicle. I recommend you do a little research before pretending you know better.

Since most of your post doesn't make much sense, I'll just focus on the one question you asked:

Because it's not a good idea. It's wasteful (not fuel efficient), and it damages the battery.
I would like others to weigh in, but my research tells me that these have a high amperage alternator that is boosted to apply 300+ volts to drive motor and charge. Imperically I can sit and watch the engine alone charge the battery banks from 14.8v. Per bank 280v calculated at 42.7 SOC. to 16.2v per bank 314.8v calculated and 46.7 SOC. So the alternator is capable but set too low for in town efficient use. Local mecjanic said they were told by GM that lots of stop and go driving will keep from being in auto stop. Seems there is some way to make more efficient like Outlander is. Just had a passenger tell me their outlander stays on battery mostly rhrough city. These should too. Im looking for GM engineer on here.
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Old 12-06-2017, 11:40 AM
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Default Re: More battery pack data

Your research is completely wrong, which suggests you've done no research whatsoever. The car does not have an alternator. It has two motor-generators:

https://www.thoughtco.com/what-is-a-...e-hybrid-85455

What you also don't understand is that SoC, block voltage, current and direction of current are all interrelated, which makes it essentially impossible to equate voltage to SoC.

Other things you don't understand:
1) charging is less than 100% efficient.
2) discharging is less than 100% efficient.
3) 100% of the propulsive energy used by the car ultimately comes from gas.
4) Running in pure EV mode is false economy in most conditions.

As a result, running the engine exclusively to charge the battery is always worse than using the same engine power for propulsion.

Hybrids get better mileage by:
1) auto-stop.
2) storing kinetic energy as chemical energy by charging the battery during braking.
3) Using electrical power to replace/supplement gas power during the most inefficient phases of gas engine operation.
4) Providing low level charge during peak gas efficiency operation.

Outlander is a PHEV with an all electric range of 32.5 miles maximum. Comparing a hybrid to a plug-in is about as valid as comparing a non-hybrid to a hybrid.

The usable capacity of the GM hybrid battery is equivalent to 2 large 12V batteries with maybe 3 miles of pure EV range if under completely optimal conditions.

Again, do some more research before thinking your gut or intuition has any value whatsoever. Yes, the GM engineers could have done things better, but what you want is not possible and not beneficial.
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