PV1
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EVBatMon Readings

Fri Apr 01, 2016 8:30 am

In order to mirror the thread structure used for CaniOn, the main thread for the Android app EVBatMon was moved into the Instruments sub-forum, as that thread regards the app itself, which is an instrument.

This thread is to be used to post and discuss the data provided by EVBatMon. This thread deals only with the data, so anything regarding issues/changes to the app itself, please use the thread linked here (viewtopic.php?f=25&t=3022).
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pbui19
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Re: EvBatMon

Fri Apr 01, 2016 2:14 pm

So how does it work ? do we have to drive until the turtle shows up then charge to max capacity ? or the system has already been monitoring the capacity ?

JoeS
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Re: EvBatMon

Fri Apr 01, 2016 2:33 pm

pbui19 wrote:So how does it work ? do we have to drive until the turtle shows up then charge to max capacity ? or the system has already been monitoring the capacity ?
pbui19, we've had lots of discussions on this forum as to exactly how capacity should be measured, pointing out the errors associated with capacity calculations based on whether charging or discharging and to what limits, inability to control either charge or discharge rates precisely, differences if incrementally measuring at different SoC levels, and lots of other variables.

I suspect that EvBatMon's exact algorithm is their trade secret. :geek: Be interesting to see what the differences are between how EVBatMon does it and an 'official' Mitsubishi test.

BTW, I moved your post over to this thread as we'd like to keep the other thread focused on getting EvBatMon working in the car and issues with that.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
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PV1
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Re: EVBatMon Readings

Fri Apr 01, 2016 3:16 pm

The capacity showed up immediately after the app connected to the car. Apparently, they found where the car stores this information. I was under the impression that the MUT-3 requested this info, but apparently it's available on the CANBus.
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
Solar-powered since 10/10/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

2017 Bolt EV LT in Orange with QC - 7/31/2017

Driving electric since 2-21-2013.

Malm
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Re: EVBatMon Readings

Fri Apr 01, 2016 3:31 pm

PV1 wrote:The capacity showed up immediately after the app connected to the car. Apparently, they found where the car stores this information. I was under the impression that the MUT-3 requested this info, but apparently it's available on the CANBus.


I believe it does. So the number showed by EvBatMon is exactly the same as the MUT-3 at the Mitsubishi service. My data is in line with that idea. In the beginning of February MUT-3 showed 34 Ah in the Mitsubishi service. When I obtained for the first time the value with EvBatMon, in 13 of March, it showed 33,8 Ah, and now is at 33,7 Ah. It's always available on the CANBus. I always thought that it was there. My warranty is going to end next week, and I asked today for a new battery. I said I have a big drop in range compared to 2011, only possible to explain by one much more bigger drop in capacity that Mitsubishi suggested five years ago (20% in 5 years). There are many ways to see the actual state of my i-MiEV. Since almost nobody understands how does my i-MiEV is (but I do), I think I can have a chance. I have some astonishing values from 2013, like 175 km mRR and a trip of 201,4 km with 3 bars left, and now most of the days I only have something like 80 km of mRR, and that trip can't be done anymore, even arriving after 7 km in turtle. These are the facts that I will use to make my point. It sounds very bad, because I want to show the worst possible picture. The real picture, the true picture, I know very well and the 33,7 Ah says it all, almost 30% of loss of capacity, but not so much in relation to the loss of the inicial range (when it was new, it didn´t used a significant percentage of its capacity, so I never had avaliable all the capacity, stopped at 0,0% SoC but with the lowest cell with 3,6 V - now it goes to 2,7 5V).
Last edited by Malm on Fri Apr 01, 2016 4:01 pm, edited 2 times in total.
Riding an i-Miev since 4/2011 in Portugal, 100.000 kms.

PV1
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Re: EVBatMon Readings

Fri Apr 01, 2016 3:51 pm

I also like how the remaining Ah are shown. I've been tempted to put a feature request in for CaniOn to show Wh remaining, but Ah remaining is probably a better value to show.

I also pegged 45.4 kW of regen!
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
Solar-powered since 10/10/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

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kiev
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Re: EVBatMon Readings

Fri Apr 01, 2016 6:38 pm

i may have posted this procedure from the FSM before,

miev capacity check

To just read what the stored capacity value presently is:

1.Connect the diagnosis connector to the M.U.T.-III with electric motor switch in the "LOCK" (OFF) position.
2.From the System Selection Screen of the M.U.T.-III, select the "BMU".
3.Select the "Data List" from the BMU Screen.
4.Check the BMU data list, item No. 23: Battery current capacity.
5.Turn the electric motor switch to the "LOCK" (OFF) position, and disconnect the M.U.T.-III.


It's just a matter to determine what the CAN id is for the BMU data list item #23, then it could be read by Canion or other CAN reader--it was on my to-do list once i got my hands on that mut...
kiev = kenny's innovative electric vehicle

JoeS
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Re: EVBatMon Readings

Fri Apr 01, 2016 11:01 pm

So, why the rigmarole the dealers subjected some of our members to in order to measure capacity (e.g., charge fully and drain battery using heater), not to mention a dealer telling me they couldn't do it?

Malm, since you have a good handle on this, how do your EVBatMon (CAN) numbers compare with various other techniques for determining capacity? Incidentally, wish you all the best in getting Mitsubishi to replace your degraded (but not broken) pack. The magic number for Leaf and Kia, IIRC, is 30% capacity loss; i.e., down to 70% of original capacity.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
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zzcoopej
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Re: EVBatMon Readings

Fri Apr 01, 2016 11:17 pm

JoeS wrote:So, why the rigmarole the dealers subjected some of our members to in order to measure capacity (e.g., charge fully and drain battery using heater), not to mention a dealer telling me they couldn't do it?


There is not much to service in an EV, so the dealership has to be useful for something?

It is true, there are 2 battery capacities - true, and calculated (eg PMC, SOH). The actual true capacity can only be determined by a complete discharge from full under controlled conditions. However the capacity can also be calculated based on driving. Over time with a healthy battery this calculation can become quite accurate and is what EvBatMon reports as PMC (Percentage of Manufacturer's Capacity). However with an unhealthy battery, degraded capacity is a moving target and the calculation may not be as "scientific" as it is not based on a precise and constant load (however it could be argued that it is more accurate as it represents the actual driving experience).

When you get a normal service at the dealership, they report the same BMU calculated capacity as EvBatMon does. If this calculated capacity (or the cell voltage range when the battery is flat) indicates a problem, you should still get the full tested capacity.

EvBatMon App for iMiEV/C-Zéro/iOn
Android https://play.google.com/store/apps/details?id=com.EvPositive.EvBatMon_iMiEV
iOS (iPhone,iPad,iPod) https://itunes.apple.com/us/app/evbatmon-for-mitsubishi-imiev/id1143905475
www.EvPositive.com

Malm
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Re: EVBatMon Readings

Sat Apr 02, 2016 2:00 am

JoeS wrote:So, why the rigmarole the dealers subjected some of our members to in order to measure capacity (e.g., charge fully and drain battery using heater), not to mention a dealer telling me they couldn't do it?

Malm, since you have a good handle on this, how do your EVBatMon (CAN) numbers compare with various other techniques for determining capacity? Incidentally, wish you all the best in getting Mitsubishi to replace your degraded (but not broken) pack. The magic number for Leaf and Kia, IIRC, is 30% capacity loss; i.e., down to 70% of original capacity.


Determining capacity by discharging it to 20% and then charging it to 100%, in my opinion, doesn´t work. Why? 1 - Because SoC can sometimes jump for another number in a millisecond. 2 - Because 20% of SoC can be 35% of real charge of the battery (specially in a new car, at this stage the car can stop at 0,0% SoC with still 3,6 V in the weakest cell), at 0,0% SoC the car will be 15% full. 3 - A 100% charge is not always to 100% full, sometimes the charge stops at 359/360 total voltage, and not at 361V.

Before I had EvBatMon I had my own method. See the voltage at 0,0% SoC by Canion and how much was a bar of 5% in energy (50-55%) when charging. If the car can go to 0,0% SoC and one bar of 5% is about 630 Wh, then I think the car has a range of a new one and the remaining capacity will be over something like 42 Ah. I tested some second hand i-MiEVs for some of my friends with this method and it worked well.

For me, the best way to know the capacity in an i-MiEV is this number given by the EvBatMon. Yes, it can be not very well calculated in a old battery with cells much with more degradation then the others (I agree with zzcoopej).
Riding an i-Miev since 4/2011 in Portugal, 100.000 kms.

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