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Discussion Starter · #1 · (Edited)
Hello
The 500e is a wonderful hauler even if the range is a bit short .... More so with how it's reporting the battery health. I just don't get it.

Wheel Tire Vehicle Automotive tire Car




It reports Battery health and SOH-R at 99-100%
But SOH-C is at 74% witch according to my understanding should follow SOH-R and the available amperage is just 45aH .
Did the test at draining the battery until it the stopped moving and the charged it up. It didn't go that far when meter reached zero and only result was the gauge showed 95% at full charge for some time after
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Also the cell balancing seams more than okay with with the lowest and highest being under10mV difference. It also passes all test.

Full log in the attachment.

Could there be some limiter left on from when the car had the app available? I seriously don't get why it's reporting such a low usable battery

I would also like to trick the stupid park motor so i could remove it. It's annoyingly slow to get in to drive when you come from a manual car. Would be happy to just use the handbrake... But that's for another time for now.
 

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All of those numbers are bogus and highly variable. They are not to be trusted.

As @Electric Tire Shredder has pointed out in several different threads, there is really only one way to determine the true battery capacity of a 500e:

1. Run the battery down to 0%.
2. Then run the battery down to the 12V DC-DC cutoff. ETS suggests doing this by engaging the emergency brake, then applying power with the accelerator. You can also add other loads such as lights and heater (which will cut off before you reach bottom). For obvious reasons you do this parked at a charging station. Specifically a charging station that will report the total number of kWh transferred, like a ChargePoint. Once you've reached the 12V DC-DC cutoff, the 12V battery will register 12-13V instead of 14V because the DC-DC connected to the high voltage battery is no longer charging the 12V battery.
3. Charge the EV fully to 100%. The kWh transferred is in fact the capacity of the battery since it was charged from completely empty to completely full.

Then and only then do you have the data to determine the capacity. If the batteries are truly at 45 Ah then the energy transferred would by 4.15V/cell * 96 cells * 45 Ah -> 18 Kwh. However, if it transfers 21 or 22 kWh then the capacity is much higher than that. The maximum is 60 Ah, which is just a shade under 24 kWh.

I really don't like that EVs often deliver bogus battery information. Because of it, folks who really have no idea what's going on (which ends up being all of us) make a determination that the battery is faulty due to faulty data. I think it would be better to give no information at all than to deliver unreliable information.

ga2500ev
 

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Peak voltage is limited to 4.1 volts per cell. That would give 17.7 kWh for a 45 Ah pack. If charging efficiency is 90%, then expect to see 19.66 kWh put back into the pack.

Your log shows 48.6 Ah of total capacity.

Another thing to check is a log at a low SOC and see what the lowest cell voltage is compared to the highest. This will give you an idea if you have a weak cell.
 

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Discussion Starter · #5 ·
Separate question: What kind of range do you get when the hauler is attached? What's the miles/kWh or MPGe for trips with it attached?

ga2500ev
Summer with mixed city and 50-60mph roads and not kind to the accelerator. 1% equals pretty much one km, so range is about 60? miles then. Never really exactly calculated other than I can get where I need to in day to day life since i haven't filled up the petrol car since i got the Fiat half a year ago and a lot is with trailer attached :)
 

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Discussion Starter · #6 ·
Summer with mixed city and 50-60mph roads and not kind to the accelerator. 1% equals pretty much one km, so range is about 60? miles then. Never really exactly calculated other than I can get where I need to in day to day life since i haven't filled up the petrol car since i got the Fiat half a year ago and a lot is with trailer attached :)
All of those numbers are bogus and highly variable. They are not to be trusted.

As @Electric Tire Shredder has pointed out in several different threads, there is really only one way to determine the true battery capacity of a 500e:

1. Run the battery down to 0%.
2. Then run the battery down to the 12V DC-DC cutoff. ETS suggests doing this by engaging the emergency brake, then applying power with the accelerator. You can also add other loads such as lights and heater (which will cut off before you reach bottom). For obvious reasons you do this parked at a charging station. Specifically a charging station that will report the total number of kWh transferred, like a ChargePoint. Once you've reached the 12V DC-DC cutoff, the 12V battery will register 12-13V instead of 14V because the DC-DC connected to the high voltage battery is no longer charging the 12V battery.
3. Charge the EV fully to 100%. The kWh transferred is in fact the capacity of the battery since it was charged from completely empty to completely full.

Then and only then do you have the data to determine the capacity. If the batteries are truly at 45 Ah then the energy transferred would by 4.15V/cell * 96 cells * 45 Ah -> 18 Kwh. However, if it transfers 21 or 22 kWh then the capacity is much higher than that. The maximum is 60 Ah, which is just a shade under 24 kWh.

I really don't like that EVs often deliver bogus battery information. Because of it, folks who really have no idea what's going on (which ends up being all of us) make a determination that the battery is faulty due to faulty data. I think it would be better to give no information at all than to deliver unreliable information.

ga2500ev
If the battery indicator is about accurate. The capacity is exactly what the obd suggest. The stations at work always suggest exactly about 7-8kw/h when it's about 50%. Highest I ever seen is 14kw/H and then it was quite run down. So no I say the readings and info are accurate.
Question is is they really that worn or if there is a limiter on.

Anyway, have to get a reading with a low charge and se the cell voltage then
 

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Answer: No, it's likely not that worn, but it doesn't seem to matter much, since the car can get where you need to in day to day life.

As @ga2500ev mentioned, all the SOH numbers in OBD are extremely unreliable. For example, many users report Ah loss numbers anywhere from an unbelievably-low 0.1% or less per 10k miles, all the way to an unbelievably-high 10% or more per 10k.

IF you want to estimate capacity like in post #2, you have to take it all the way to 100% first, in order to fully balance the cells. Otherwise, when you recharge, the meter will show extra energy for balancing, giving the false impression of higher battery capacity. After going to 100% & doing your normal drives, discharge to motor shutoff, using the FOOT brake to lock the wheels while you apply a bit of power.

The EPA's "dead-to-full" spec is 25kWh to recharge, presumably at room temperature, so try to copy that too. Just divide your meter reading by 25 to get your approximate % of new capacity.
 

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If the battery indicator is about accurate. The capacity is exactly what the obd suggest. The stations at work always suggest exactly about 7-8kw/h when it's about 50%. Highest I ever seen is 14kw/H and then it was quite run down. So no I say the readings and info are accurate.
Question is is they really that worn or if there is a limiter on.

Anyway, have to get a reading with a low charge and se the cell voltage then
It is virtual capacity since the useable HV battery capacity is managed to extend the life of HV battery. There are buffers put into the HV battery that try to maintain the HV Bat SOH-C: near 75% giving you about 25% buffer. This buffer will go down as the battery resistance increases. I think that as the HV Bat SOH-R: goes down from 100% the buffer will get smaller so the HV Bat SOH-C will go up.

The HV Bat SOH is the most important number.

If you are getting 60 miles of range towing that large trailer you are doing very well. Especially at 60 mph.
 

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Discussion Starter · #9 ·
Answer: No, it's likely not that worn, but it doesn't seem to matter much, since the car can get where you need to in day to day life.

As @ga2500ev mentioned, all the SOH numbers in OBD are extremely unreliable. For example, many users report Ah loss numbers anywhere from an unbelievably-low 0.1% or less per 10k miles, all the way to an unbelievably-high 10% or more per 10k.

IF you want to estimate capacity like in post #2, you have to take it all the way to 100% first, in order to fully balance the cells. Otherwise, it will use extra energy to do that later, which will give the appearance of higher battery capacity. THEN after doing your normal drives, discharge to motor shutoff, using the FOOT brake to lock the wheels while you apply a bit of power.

The EPA's "dead to full" spec is 25kWh to recharge, presumably at room temperature, so try to copy that too. Just divide your meter reading by 25 to get your approximate % of new capacity.

It would matter since I could actually charge when it's cheap. Right now you always have to charge. Spot prices warry from 1 to 50cent/kwh sometimes over a day.

I have tried to have it in drive and give gas and it shuts down after a while due to overheating as it should. You are just heating up the engine windings by doing, who really came up with that idea? Anyone that has played around with a Frequency unit should now how quickly you can destroy engine windings. (have done it a couple of times my self 😇 with an oversized drive and small motor)
 

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At least 2 users reported successfully giving it a LITTLE bit of "gas" so it takes less time to go from 0% to motor shutoff.

I think I finally understand your motivation now: The numbers look low, so you thought maybe there was some "reserve" power you could access in order to be able to keep driving & charge later at a lower rate, right?

Unfortunately you've already done as much as you can in that regard, by resetting the % gauge with full discharge.
 

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Discussion Starter · #11 ·
At least 2 users reported successfully giving it a LITTLE bit of "gas" so it takes less time to go from 0% to motor shutoff.
Well it really is not something people should go round and recommend. I seriously burned one winding in less than minute and it was at just 20hz when the engine got stuck and it took some time for me to get to the drive.


Well yes
This is tomorrows price
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makes quite a difference already from 1 - 34 cent/kwh at peak.
 

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Okay, thank you. Users could be inducing motor shut-down due to overheating, before they reach the goal of motor shut-down due to low battery. Now I need to change my instructions back to just driving until it's nearly 0% on OBD, & then park with everything turned on, until it shifts itself out of D. (I guess that's the easiest way, in case any "motor shutdown" warning doesn't stay on the screen)
 

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SOH-R and SOH-C are different ways to estimate the battery capacity as this article explains:

However, the number of Ah is imho the best estimate of the capacity, but unlike gas cars you don’t want to get close to zero anyway…besides the risk of getting stranded, it’s not healthy for the battery.
 

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SOH-R and SOH-C are different ways to estimate the battery capacity as this article explains:

However, the number of Ah is imho the best estimate of the capacity, but unlike gas cars you don’t want to get close to zero anyway…besides the risk of getting stranded, it’s not healthy for the battery.
I don't see it. Can you copy and paste the specific paragraph? Thanks!
 

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As it relates to this thread, it seems to me the very reason for the article is that it's not easy to accurately determine capacity outside of a laboratory.

That may be the reason why "All of those numbers are bogus and highly variable. They are not to be trusted.", as @ga2500ev stated so well.

The article is the first place I've seen a number for the temporary battery capacity loss when cold*. It equates to a whopping 10% less driving range at 30°F than at 100°F. That's in addition to the extra drag due to cold air being more dense.

It also means that if we're not at the right temperature to measure our ~2% loss per 10k miles, we'd be significantly inaccurate.

* "enhancement of battery capacity by 7.7% at 45 °C in comparison to 15 °C". Click to enlarge:
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unlike gas cars you don’t want to get close to zero anyway…besides the risk of getting stranded, it’s not healthy for the battery.
Agreed, except I don't like to get close to zero in a gas car either! If there's a power outage you can't fill up.

Also, what we were discussing was discharge past zero just once, to reset an inaccurately-low % gauge that's hiding usable range from the driver. The slight impact on battery health is why I recommend to not even bother:

 

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Discussion Starter · #18 ·
Can report back now that I happend to be at 0% at our company that has chargestations with meters that are inspected. From 0-100% 18,5kwh. So the obd report is I would say a 100% correct.
Quite a huge degredation
 

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Can report back now that I happend to be at 0% at our company that has chargestations with meters that are inspected. From 0-100% 18,5kwh. So the obd report is I would say a 100% correct.
Quite a huge degredation
Is that 0% as reported by AlfaOBD or by the dash display? Or what was the per cell voltage? When I took my car down to where it wouldn't move anymore, the individual cells were around 3.0X to 3.1 volts.
 
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