JoeS
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Posts: 3537
Joined: Thu Dec 15, 2011 5:47 am
Location: Los Altos Hills, California

Re: Charging Interruption

Sat Jul 13, 2013 8:57 am

We had discussed the charge interruption on a number of other threads, and I see that I had forgotten to update this one. I had posted these screenshots off my TED5000 display (taken on the evening of 22 March, 2012) elsewhere, but am repeating them here -

The red line represents line voltage and is the nominal 120vac off one of the two power input legs.
The green line (kW) is the day's tail end of my solar generation, showing it decaying to zero as it got dark.
The orange line (kW) represents my other EV charging and is showing zero as nothing was charging.
The blue line (kW) represents my iMiEV, charging at a nominal 240vac.

Image
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You can see that about an hour into the charging process the charger paused for a few minutes by itself before starting back up. This is normal, and I surmise that this is part of the BMS testing to see if any cell(s) exhibits an inordinate voltage drop when power is removed. At the end of charge you can see that from the point the power draw starts to decay to the actual cut off by the charger the time is about an hour.

In their cell monitoring unit update reprogramming last year, Mitsubish evidently changed the timeout duration from a nominal ten minutes to six minutes, although I've seen longer durations occasionally, but have never seen TWO timeouts in one charging session.

Don wrote: I told my wife I could easily spend nearly as much money and the better part of a year of my time and still not be able to build an EV half as good as this one.
OT. As the owner of two EV conversions and a couple of spartan high-performance single-seater Sparrows, I completely agree with Don that a DIY conversion of an older vehicle nowadays is definitely not cost-effective (but it's a great father-son/daughter technical project). Don't forget, there were virtually no production EVs available for years, and an EV conversion was the only game in town. We're at the dawn of a new era...
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
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

JoeS
Site Moderator
Posts: 3537
Joined: Thu Dec 15, 2011 5:47 am
Location: Los Altos Hills, California

Re: Charging Interruption

Fri Apr 27, 2018 2:35 pm

Thought I'd revive this thread as DBMandrake interjected some new thoughts into this old subject in the Topic Is my battery dying?

Specifically, in that thread -
DBMandrake wrote:...If the car is at 2 bars or less when you start charging it sometimes after about 10 minutes charging "pauses" for up to 30 minutes where the car and charge point says the car is still charging but the power drawn drops from 3.3kW right down to about 30 watts. I can only assume balancing is occuring, I have not tried putting my diagnostic tool on to confirm this but I think it's a fair bet.
Over the past six years the charging "Timeout" has been addressed or buried in many other threads as well - here are a few I found -

http://myimiev.com/forum/viewtopic.php?f=23&t=1356&p=7933

http://myimiev.com/forum/viewtopic.php?f=9&t=773&p=5627

http://myimiev.com/forum/viewtopic.php?f=9&t=686&p=4932

http://myimiev.com/forum/viewtopic.php?f=24&t=1894

http://myimiev.com/forum/viewtopic.php?f=23&t=3811

Specifically addressing whether a low SOC (two bars or less) is required for this Timeout to occur, I can confirm that it does not. Over the last couple of days I looked at the power consumption graph for my i-MiEV for two charges: the Timeout occurred both times, and each time I started charging from about seven bars. The Timeouts each lasted about six minutes. The first time the Timeout started about forty minutes after I started charging, and the second time it occurred about 1-1/2 hours after I started charging.

Look a look at the previous post on this page to see a graph of the car's power draw and Timeout while charging.

Now, what we have are two ideas as to what's going on:

JoeS: the Timeout is used to measure voltage sag while charging is temporarily suspended; if it's excessive, the charging would be aborted (I don't know of any instance when that has occurred). I've seen this feature on conventional 12v lead-acid chargers.

DBMandrake: Timeout is used to allow cell balancing at a low SoC (in addition to the usual top-balancing that occurs at the end of a full charging session)

I like DBMandrake's hypothesis as it would explain the variable nature of this Timeout duration, ranging anywhere from 6 minutes to 20 minutes (or even more?).

Just thought I'd reopen this topic, in case anyone is recording CaniOn during this Timeout to confirm DBMandrake's hypothesis that the cells are being balanced during this interval.
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
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

DBMandrake
Posts: 54
Joined: Mon Mar 20, 2017 4:57 am
Location: Scotland

Re: Charging Interruption

Tue May 01, 2018 1:40 am

JoeS wrote:Just thought I'd reopen this topic, in case anyone is recording CaniOn during this Timeout to confirm DBMandrake's hypothesis that the cells are being balanced during this interval.

As far as I know, Canion can't report the state of the cell balancers ? In which case you could only infer that balancing was occuring by watching for changes in cell voltages.

Diagbox will report the state of each individual cell balancer in real time (active / inactive) and you can see them flicker on and off towards the end of the charge cycle.

I have not had a chance to put Diagbox on the car during a "bottom balance" at 2 bars to see if it is truly balancing that is occuring, as it's difficult to predict when/whether it will do it, and getting the laptop out, connected, booted up and in the right diagnostic screen of Diagbox is a bit of a hassle. But maybe one day I will catch it, especially now I have Canion and a splitter cable so I can run Canion and Diagbox simultaneously.

Display of the status of the cell balancers in Canion would be a great feature if it could be added - the way I would visualise it would be to change the colour of the voltage bar of a cell whose balancer is currently turned on to something other than blue. Then you could see the relative voltages and the action of all the balancers at a glance in a very intuitive fashion... :)
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

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