Best charging practices for battery longevity

[Don]

What about using a light timer? You can buy one at a local hardware store for $5. They have some rated for 15 amps so good enough at the 110 charging level. Easy to set start and stop time mechanically.

I have two mechanical timers - One for 120 and one for 240, but truth be told, I rarely use either one to do the charging simply because readjusting them for each individual session is such a pain - I *thought* they were going to be a great idea, but it just didn't work out that way

What I do now is a quick mental calculation of about how long it needs to charge, depending on whether I'm using 240 or more likely 120 and then I set the kitchen timer for the time I think it needs and go unplug it when the timer chimes. After awhile, you get pretty accurate with your time guesstimation, so I only need one trip out to the garage. If it's not quite 'done', I just give it half an hour or so more and then unplug it

Don

 

[JoeS]

This thread has diverted into a number of separate topics:

1. Best charging practice for Robb's situation
2. Remote use with Leviton L2 EVSE
3. External timers

1. If we could, please, let's address only charging practices on this thread.
2. I've started a fresh thread to address Robb's issues with the Remote and his Leviton
3. Here's the thread for manual timers Better Charging Controls

You'll understand my frustration when you try to find some of the excellent points being made six months from now.

 

[JoeS]

... It would be most convenient to simply plug my i into the L2 charger every night and know that I will wake up in the morning with a full "tank" that will take me everywhere I need to go and then some....

RobbW, the body of knowledge regarding large-format Lithium-Ion batteries of various chemistries has been increasing over the last few years. You will not only find a great deal of speculation by some of us on this forum (especially in the early days), but also links to various studies as they have appeared. There are lots of similar discussions on the Leaf and Tesla forums. So far we do not appear to have the hot-climate issue as the Leaf.

The more I read, the less I worry about the projected life of our iMiEV traction pack; however, some definite do's and don't are emerging, the most important one is that subjecting batteries to high temperatures is bad. Since there's little we can do about that in our daily lives (we all do park in the shade, don't we?), about all we can do is avoid high SOC (State Of Charge) at high temperatures, and especially leaving the car sitting for extended periods of time at high SOC in a hot climate.

For now, in your case, I would simply learn to program the Remote to start charging at some time at night so that you've just reached 16 bars when you're ready to leave for work. Figure 3 bars/charginghour using L2 or 4bars/5charging hours using L1. You've probably already noticed that you're arriving home with a half-dozen bars on your fuel gauge after a 'typical' day's commute. As you get comfortable, you can probably start playing with the timer to terminate your charge at around 14-15 bars. In these early days of iMiEV ownership, don't worry about it as it's more important that you develop a feel for the car's range in response to your driving habits.

 

[9h1bw]

I have been reading that a traction battery should not be full charged. Does this also apply to the iMeiv?
I charge mine at home and the charger keeps on charging up to 16 notches. Is this OK or should I stop it before. If yes up to which notch should it be charged?

 

[JoeS]

9h1bw, I moved your post over to this thread. Your question is one we all asked in our early days of ownership, and there are many threads on this forum dealing with this topic, this being just one of them.

Now, after six years of experience and a much larger body of data and quite a number of controlled studies, some generalizations have emerged -

The most degradation to Lithium Ion batteries is caused by high temperature AND high state of charge. Second to that is attempting to rapidly charge the battery at very low temperatures. In both of these, our Mitsubishi battery management system tries to protect it but, for example, can't do anything if you fully charge the battery and let the car sit unused in a very high temperature environment (cringe).

In my own case, the only time I fully charge the car is JUST BEFORE I take off on a long trip; otherwise, I normally charge to about 12 bars (using either the Remote or a mechanical timer to stop the charge) and almost never let the charge level drop below two bars (in over 80,000 i-MiEV miles we've never seen turtle). Also, if you leave the car unused for a few weeks, leave it at around 4-6 bars (some say lower) and be sure to put a float (not old-fashioned 'trickle') charger on the 12v battery.

Our i-MiEV battery pack and its BMS is wonderfully rugged and when conservatively maintained has been able to provide an almost un-noticeable difference in the car's range after many tens of thousands of miles - speculation being that one of the reasons is that any capacity loss merely takes away from the turtle 'reserve' and is thus invisible.

 

[phb10186]

I think that the charging to 12 bars is one that more should adopt - It's a shame there isnt a dial charge stop in the car, where you can preset the max charge. Just thought that that would be a good idea - the remote is not the best device out there, but I suppose it does work.

 

[Don]

I think that the charging to 12 bars is one that more should adopt - It's a shame there isnt a dial charge stop in the car, where you can preset the max charge

Many EV's do indeed have that feature. I wish ours did too. We rarely ever recharge either of our cars to 100% . . . . unless we just forget to go unplug them in time. A full recharge every 4 or 5 weeks is probably a good thing . . . . and in spite of our best efforts, we forget to unplug in time at least that often

Don

 

[Luddite]

Nice to see these forums are still alive!

I am a relatively new owner of an ion, but I noticed that the manual of the i-miev (US version) states that
"What do I do if I need to store my mitsubishi i for a long period of time?

Do not disconnect the battery or any of the i's cables. Make sure the battery's energy level gauge shows 2-4 bars and make sure all lights are turned off. Do not leave the battery charged with more than 4 bars as this will severely decrease the main drive battery's overall lifespan. Check the battery residual every three months and if you see any discharge, please charge to 2-4 bars. Try to avoid storage in a hot or cold environment."

The peugeot ion/citroen c-zero manual both state that

"When your vehicle is going to be out of use for a long period, charge the main battery completely every three months (following the normal
charging procedure)."

They can't both be right so can anyone explain this one?
Not that I ever plan on storing the car - I plan on driving it!

Don,have you used canion to see your battery's capacity?
Have you repaced your 12v battery yet?
That's the battery I'm more worried about!

 

[Don]

I think they want you to plug the car in periodically to maintain the 12 volt battery - It recharges when the traction battery does, so 30 minutes or so would top it off and add next to nothing to the traction battery using the USA version 8 amp, 120 volt EVSE . . . . or, since they say to fully recharge it periodically, maybe then drive it far enough to get the traction pack back down to 3 or 4 bars?

Yes, I replaced the 12 volt battery in our original car (purchased in May of 2012) with a Miata AGM battery. The one in the other car is still going strong. We had the original car stored for about a year and did NOT plug it in occasionally to keep up the 12 volt battery and that may be why it needed replacing. Should have removed it and put it on a trickle charger

Nope - Haven't tried Canion yet

Don

 

[JoeS]

Luddite, welcome to the forum! Whereabouts in Scotland are you (I was born in Edinburgh)?

...I noticed that the manual of the i-miev (US version) states..."What do I do if I need to store my mitsubishi i for a long period of time? -
Do not disconnect the battery or any of the i's cables. Make sure the battery's energy level gauge shows 2-4 bars and make sure all lights are turned off. Do not leave the battery charged with more than 4 bars as this will severely decrease the main drive battery's overall lifespan. Check the battery residual every three months and if you see any discharge, please charge to 2-4 bars. Try to avoid storage in a hot or cold environment."

Wow, I immediately pulled out my 2012 manual and went looking and could find no mention of storage charge. We have at least one thread on this forum discussing just that topic, and 2-4 bars sounds better than 4-6 bars. I recall attending a presentation where it was shown that Leafs are shipped at 25%SoC.

Beats me why the European manuals state that the battery should be fully charged - perhaps the tech writers failed to consult with the battery engineers (who failed to catch this when they reviewed the manual) and are going by the old 12v lead-acid protocol?

What is important is that the 12v battery be maintained, and a float charger would do that just fine or, if outdoors, a small solar panel with a regulated output would suffice.

Whereas CaniOn is a great i-MiEV app, the app EVBatMon provides a direct capacity readout from the car itself.

 

[Luddite]

Thanks for the quick reply guys.

Don, wouldn't starting the car also charge up the 12v battery when storing long term?

12v battery concerns me more than the traction battery - seems strange that it's a battery you have to top up instead of a sealed unit like most ICE car batteries. Don't want to pay dealer to replace it - would rather do it myself but my car came without a user manual so I don't know the code for the radio. I'll maybe connect up the 12v battery to charge every so often but should this be a problem if driving the car almost every day?

The following Transport Evolved video claims that the reason the 12v batteries die is that electric car 12v batteries do not have high loads going through them as would be the case with an ICE car and the high starting current in an ICE car "breaks down deposits that have built up on the plates of the battery over time"
Would using the 12v battery with a higher powered inverter help to do this or would it not draw enough power?
(I am aaware that it probably needs to be replaced at some time soon (as it would with an ICE car) but I want to maintain both my batteries well!

https://www.youtube.com/watch?v=pu30bchGu50&t=199s


I would be interested to see my traction battery's actual capacity so may have to buy the obd adaptor and hook up canion (or EvBatMon)
The car only has 25,000 miles on it but is coming up for 7 years old.
I think it was used fairly frequently but it may have been fully charged every day with the "granny charger" - 240v - 10A ~2.2kw and charged when the battery already had a high SOC.

Apparently it has never been charged using CHAdeMO although not sure if this would make much difference with non-frequent CHAdeMO charging. It rarely gets above 20C (~70f) here anyway so do'nt know if I should start using the quick charger and go on some more challenging journeys - I don't like pushing the battery to its limits. In 500 miles of ownership, I've never let the battery go below 5 bars.

Luddite, welcome to the forum! Whereabouts in Scotland are you (I was born in Edinburgh)?

JoeS, Thanks. I'm currently residing in Dundee. We currently have free parking for all pure EV's in Dundee and free charging/quick charging but not free parking for hybrids - there were too many mitsu outlander PHEV's bay blocking.
Mainly charge up from home anyway but it's good to know the network is expanding - free charging in most of Scotland

 

[jray3]

Since no simple and easy 80% option emerged during the first few years of ownership and we need most of the range on a regular basis, the only coddling that my battery gets is a 4-bar storage State Of Charge when we leave town. The longest hibernation has been two weeks at low SOC, though my car sat on the dealer's lot for a full year, probably at a high SOC. Otherwise we use it like an appliance, charging to 100% at least once per day, often twice. As spring warms up around here I've seen several RR mornings above 80 miles, so battery health is still good as we approach 70 k Miles on MR BEAN.
I haven't used CanIon in a while, as my last cheap Android tablet bit the dust. Sure wish there was an Apple version.

 

[Luddite]

Thanks for the reply jray3.
Good to hear that Mr bean is keeping well!

To you ever charge using CHAdeMO?
Since my car is new to me I have been charging up to 100% when I've been making longer journeys (40 miles with 30 miles of freeways - 70mph traffic) Today I drove after charging up to 13 bars and had 4 left when I returned.

What wears out the battery more, going down to 1-2 bars or always charging to 100%?

 

[jray3]

During the first couple years I did a CHAdeMO charge 2-3 times per week. My record for a single day is at least 10 sessions on a road trip. After gaining confidence (during dcfc network downtimes), I never use CHAdeMO any more on my regular 54 mile Saturday morning trip, plus MR BEAN can rest and recharge on Saturday afternoons as I now have hobby EVs to run errands in.

 

[FrostyCanada]

Hello Luddite, we have three different charging styles with our imiev when commuting to work.

Winter time = home or work, we immediately charge to 100% when a plug is available.

Spring / fall = we delay charge to 100% (and very close to our departure time + rarely or never charge at work).

Summer = we only charge to 12-14 bars (never charge at work or only charge if required).

Weekends = we leave the car at 50 % and only charge as require.

Brian

 

[Luddite]

Thanks for your replies jray and Brian.
I am still getting used to my car but loving it.
Why can't tesla make a more basic car? The model 3 is still too complicated with the massive screen!
A 40kwh imiev? That'd be great

 

[Don]

A 40kwh imiev? That'd be great

The Chevy Bolt has a 60 Kwh battery for those who want to go a bit farther

Don

 

[JoeS]

For those interested, here's a link to a US Army battery study:

http://www.dtic.mil/get-tr-doc/pdf?AD=ADA527711

 

[9h1bw]

Thanks gentlemen for all your input. I just noticed that someone actually answered. I must have forgot to tick the email reminder.

If I understood you all the battery should be charged to about 12 bars. That would reduce the range quite a lot. I charge the iMeiv about once a week and live in Malta which is very hilly and tasking on the battery.

So how do I go about making sure I do not overcharge It? Is it using the remote control?

 

[JoeS]

...I charge the iMeiv about once a week and live in Malta which is very hilly and tasking on the battery.

Malta is so small that the i-MiEV is a wonderful match for the island! Why do you only charge once a week? Are you unable to charge at home?

So how do I go about making sure I do not overcharge It? Is it using the remote control?

If your i-MiEV is the North American version, then it should have a Remote which can be used to program its charging - you can quickly calculate how long you need to charge to have it stop at 12 bars. If you do not have a Remote, then a simple mechanical timer (e.g., 6-hour) can do the same thing - that's what I primarily use.