Better charging controls

Mitsubishi i-MiEV Forum

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Active member
Dec 22, 2011
Mountain View, CA
The controls over when the vehicle charges leave a bit to be desired: You plug the car in, it starts charging immediately. Then you use the remote to set a number of hours of delay (in half hour increments), at which point the car stops charging and waits for that time period.

Given my electric rates, what I want is for the car to start charging after midnight, no matter when I bring it home and plug it in. That's because I'm on time-of-use rates with my electric company, and it is much cheaper then.

A much much better user interface for the timed charging feature would be: I set a start time (and optional end time, though I can't see much use for that) for charging that is a time of day, like, say, 12:15am. Then whenever I plug the car in, it doesn't charge until the set time comes 'round.
MtnViewMark, thanks for posting. Sounds like another gadget not completely thought-through. Never want to turn something on only to have it turn off soon thereafter.

Since the iMiEV (can't bring myself to calling it the "i") 120v EVSE limits the current to only 8A, I would imagine that permanently mounting a $5 lamp timer on your 120vac wall socket would do the trick. Simply set its on/off cycle for your desired time of use. Or is there something else you need to do after the unit is plugged in?

More significantly, when the 240vac EVSE gets installed, it may be a good idea to have it fed through, for example, an Intermatic timer commonly used for water heaters and swimming pool pumps. You could install a 7-day timer to take into account the different weekend time-of-use.

Since I'm less worried about TOU but want to never fully charge (I live up a 600' hill and would thus start off every trip by regenning), I plan on using a countdown timer to always shut off the charger input power before she's 'full'. I do that presently with all my EVs (I have five) as a safety backup, anyway.

Nice to know ahead of time so we can plan for it.
Since I have the Leviton L2 EVSE with a NEMA 6-20 plug I am going to try this 240 volt 16 amp light timer. In this case I can just plug it in.

jjlink, thank you very much for this timer suggestion - I've been looking for something like this 240v unit. In reading their manual, it looks as though their countdown feature seems to turn something ON instead of OFF at the end of the countdown.
Interesting idea with the timer! I guess that would work, although I always thought the charger needed to be plugged in and then turned on? Or if you have the car plugged in, and then plug in the charger (manually or via a timer switching it on), will the charging start without any other user input? Lots of modern day electronics, like my surround sound, require me to push the power button even if I left it on when I flicked off the power bar last time.
It is an open question on if it will work with a timer: If you follow the instructions, and plug the EVSE in to the power source first, then plug it into the car, indeed it starts charing immediately (though we don't know if you've set a delay with the remote if the delay reapplies, or is reset after it has run out...) But, as there is logic interlock with the car connector, it isn't certain that if you plug it into the car first, then power (or connect it on a timer) it will just start. We'll have to wait until someone tries it.

However, I have to admit, I feel a bit cheesed-off that after buying a $30k car, and $1k charging station - I still have to use a timer!
Yes, the timer will take some experimentation to see what works best. In the case of the Leviton EVB22-3PM the user guide says once charging is started, in the event of a power outage, when the power is restored the charging station will enter a Cold Load Pickup mode. This is a random (2-15 min) delay for the self-test start and is indicated by a flashing charging LED. The fault LED will flash momentarily while performing a self-test. Charging will resume when the self-test is complete.

So I am thing there are to scenarios to try:

1) With the timer in OFF mode connect the charging connector to the car and wait for the timer to automatically turn ON at the designated charging time and see if charging starts normally after the EVSE self test completes.

2) With the timer in ON mode connect the charging connector to the car. Then manually shut OFF the timer right after charging starts. Then wait for the timer to automatically turn ON at the designated charging time and see if the charge cycle starts normally after the EVSE self test (and random delay) completes.
Aha - careful reading of the owner's manual indicates that function of the remote might be sneakier than appeared. It seems that if you on one day, at 9pm, use the remote to delay the charging by 3 hours (to midnight), then the next day, if you plug in the car at say 7pm and turn on the remote, it will indicate 5 hours until start of charging. Seems like one will only need use the remote to enable the charge timer and not have to reset the delay each time, assuming you want a constant start time.

Now, why they just couldn't have the remote have a clock (which I realize you'd have to set...) and let you clearly set start time is beyond me. The other oddness is that it would be nice to be able to choose delay/non-delay when I plug it in - say with a button in the charging port well... Having to fumble with the remote seems awkward.

Anyhow - for now we are on 120v charging until the 240 charger is installed, so experimentation with the remote will have to wait until a few weeks.
I assume you don't have to use the remote to initiate the charging cycle, correct? Does just plunging in the car to a charge station cause it to start charging?

Its too bad they wont let us look at the owners manuals they have on-line but you have to already be Mitsubishi car owner to do that (not just on the waiting list).
I agree that the delayed charging with the remote is hokey. But, I have a possible explanation for why it is that way.

First, I highly suspect that delayed charging function was added late in the design to try to match what the Leaf has.

Second, note that the while the timing is set by the remote, but the car keeps track of when to start and/or stop charging. That is, the remote only "talks" to the car when you press the buttons on the remote. It does not send a signal to the car when the time to start/stop charging actually occurs (if the remote were to try to send the signal at the actual start/stop time, you might have set it somewhere where the signal was blocked, so the message wouldn't get through and your car wouldn't charge).

For the system the way it is, the on-board charge controller doesn't need a clock, only a timer. And, the timer doesn't even need to be very accurate. However, to start charging at 12:30 pm every day, the charge controller would need a clock. The way it is now, it only needs to know when approximately when the set number of hours have passed.

I suspect that their charge controller was already designed, or mostly designed, when the engineers got the requirement to have delayed charging. The charging controller undoubtedly already had circuits in it that could count time, but maybe not to the accuracy we expect of a clock. Mitsubishi probably decided that adding a clock or, the user interface to set the clock, would take too long or be too expensive. Getting the time from the dash clock (radio) seems like an obvious solution, but getting two pieces of electronics to talk to each other when they weren't designed to do that may not be an easy task. Add in that these components may be being designed or produced under contract by other companies, and changes can be really hard to implement late in the game.
jjlink said:
I assume you don't have to use the remote to initiate the charging cycle, correct? Does just plunging in the car to a charge station cause it to start charging?

Yep, just plug'er in, and you'll hear the contactor clunk within the charging station (EVSE), followed immediately by a blower purge of the iMiEV battery compartment. The lithium batts shouldn't be generating any hydrogen, but it's a nice safety step and gives audible confirmation that charging has commenced. I'm finding m i self opening the doors with annoying frequency to check the SOC because the key fob only has a 3 bar indicator rather than 16 bars or a NUMBER :geek: , and the i doesn't have status LEDs on the top of the dash, like a Leaf.
As the present owner of a number of EVs, I have a good feel for the time required to recharge each one based on the number of miles driven (and who drove them - my wife's a featherfoot whereas I'm a leadfoot unless I need to hypermile). I use mechanical timers to shut off the input power about when I think the car's fully charged, despite having fairly intelligent chargers and BMS.

I'm on Time-Of-Use metering, which means that between noon and 6pm my rates are extremely high (~35cents/kWh) whereas between 6pm and noon they're quite low (~9cents/kWh).

I would like to put my iMiEV's EVSE on a power input timer, set to be OFF between noon and 6pm.

Since I don't have an "i" yet and can't access the manual online, I'd appreciate it if someone could answer the following:

1. Can I preset the iMiEV's timer to charge for a preset amount of time?

2. Can I leave the EVSE input power off and will the "i" automatically commence charging when power is applied to the EVSE?

3. When charging commences, I will normally want to let it charge to what I feel is about the 80% point and would like to have pre-set a timer to do this. Feasible to do with the iMiEV's built-in timer?

My fallback is to simply do it the old-fashioned way: go back into the garage after 6pm and activate vehicle charging using a manual timer.

Any hints or suggestions from present owners?

jjlink: how did that Sunleaves timer work out?

Thank you.
JoeS: The Sunleaves timer works just fine turning on/off my Leviton L2 EVSE daily. However I don't have the car yet. They say its still on the boat. I suspect the timer will work fine.

Maybe someone could download the user manual for the 'i' for us.
Joe, I'll say Yes, Yes, and not really...
The charger will start up whether J1772 or the EVSE power supply is connected first, or if a tripped breaker is switched back on, so external timers should work just fine.
I don't have any info about how high the onboard charger takes the batteries when left plugged in for extended periods, or whether there's a periodic conditioning/balancing function that can be affected by the user.
I've experienced a couple of premature charging shutdowns. Have ruled out temperature and SOC as factors, and may have just caused it by fooling around with the remote!
The remote is hokey, but very useful. The first couple of times I tried to preheat the car, it got lukewarm and then shut off, but this morning, with proper instruction, the windshield got 100% clear and the car was toasty after less than 30 minutes, and this was after a 22 degree night with heavy frost!
Hi jjlink and jray3, thanks for the inputs. Nice to know that I can always time my charging externally without having some weird interlocks prevent that.

My own situation is that I live in the hills and invariably start every trip with a three-mile downgrade, and thus my desire to terminate charging prematurely (besides, Lithiums don't like to sit at full charge for any extended period of time). Since we don't have the option of programming the charger to stop at 80% charge (like the Leaf), I'll be stopping my charger early as I want to maximize my battery life.

Wonderful about being able to pre-condition the car while it's still plugged in. Hope I get my car in time to try it out this winter...
Woo-Hoo; solving my charger confusion :D
Now I'm an early adopter type, (early Palm user, Blackberry picker, managed to use a Windows Mobile device when forced to, love my iPhone), but this remote is shall we say, non-intuitive. Turns out that the little icon of an unplugged electrical cord actually means that the car is charging! ;) Seriously though, I now attribute my few problematic charging sessions to user interference. That is, if you plug the car in, it starts charging, but then if you set the "ON timer", it will turn off the charger.
Microsoft must have inspired an iMiEV engineer. This is just like selecting "Start" to shut down your computer...
Every time I send any timer command, charging stops for a couple of seconds while the car considers it's options. It appears to restart every time it's told to, but this will take further study. Read y'all's manuals carefully!
Since I also live 1400 feet above Hilo, I like to set the timer so the car doesn't fully charge. One reason is that there is hardly any braking provided by the regen system if the battery is full, and you have to use friction brakes on the way down. Also, I like to be able to recover some of the energy used in coming home UP the hill. The key fob timer function definitely takes some trial and error. For my normal driving...I can take four trips into town and then do a 2.5 hour Level2 charge and that leaves me with 14 bars charged.

One thing that could be improved on the next version of the car, is to be able to view the level-of-charge gauge without having to open the car door! Or have the key fob show a more accurate charge level, than just three bars.

Also, guys the only "manual" that is posted online for the 'i' on the owner's site, is the "warranty manual". The other manuals are not posted online for download or viewing. Otherwise I'd help out.
Is the charging linear or does it taper off (i.e., take more time per bar) as it approaches full? Without better external visuals, I'm hoping we'll all quickly get a feel for this and won't need to take a peek inside.