Why does Mitsubishi recommend fully charging every 2 weeks?

[Vike]

Oh, mixmike6 - [sigh].

The SCiB issue was discussed and closed long ago - please search the forum for the relevant articles (I am not obliged to undertake the effort just because you won't). Wikipedia ain't exactly the Britannica, but I'm not getting into that. Or just don't believe me - couldn't care less.

The fact is that North American i-MiEVs have never had SCiB batteries, and for good reason. They provide lower energy density, so less range than the GS Yuasa batteries (so on that specific point the Wikipedia article is specifically, utterly wrong). In Japan, the widespread availability of CHAdeMO means that an i-MiEV w/SCiB can QC multiple times in a day, so for many buyers a SCiB-equipped EV would have greater effective range. Even there, some users whose routine driving doesn't line up well with available CHAdeMO stations might prefer the GS Yuasa batteries, so I believe they're still an option (but not an expert in JDM, so research if you care).

By contrast, there is very little QC in the U.S., so there would be no meaningful benefit to outweigh the reduced range. Since, as we all know, the i-MiEV's EPA "official" 62 mi. range was deemed unacceptable by many reviewers and commentators, Mitsubishi saw little advantage in complicating their U.S. offering with an option that few would want. So they didn't. Ever.

Doesn't sound like L1 charging is inconveniencing you, so believe what you like. My advice is to folks for whom L2 charging is necessary (or even convenient), and that advice is please don't worry about it, it's fine.

 

[Don]

Vike, the only common sense I had was based on what I already knew of batteries: Higher voltage = Higher stress and temps = Not great for battery.

Our battery pack recharges at a fixed voltage no matter what you use for an EVSE and it's the exact same voltage when you use L1 or L2 - The voltage applied to the battery is the same, but L2 doubles the charge current. The battery pack has no idea what voltage the EVSE is plugged into, nor does it care. The onboard charger will accept any voltage between about 90 VAC and 275VAC but the voltage applied to the battery pack is still the exact same, regardless. There is no way you can apply a 'higher voltage' to the battery . . . . unless you're using the L3 quick charger

Yes I'll agree that 3.3kW vs 1.44kW probably seems negligible compared to 50kW but your missing the point. I want to keep my battery as healthy and as long as possible. I want to do everything I can to optimize the lifespan of the battery pack.

But you're not doing the battery pack any favors by only using L1. L1 recharges at about 5 amps, L2 recharges at about 10 amps and the battery pack would live just as long if you recharged it at 20 amps, which is what the newer Leafs with the 6.6Kw onboard charger are using. Unlike our iMiEV, Nissan has had some battery problems with the early Leafs which came with 3.3 Kw chargers - They certainly would not have doubled the recharge capacity on the newer versions to 6.6 Kw if they thought it would harm the battery in any way. Even the 6.6 Kw, 20 amp charge is in effect little more than a trickle charge for a battery which would be very happy if you recharged it at 1C (one times the battery capacity, which is 50 amps)

So, if you want to use only L1, no harm done, but don't stick with L1 just because you think you are doing the battery a favor, because you aren't - It would live just as long if we could recharge at 6.6 Kw

You say that the battery from the Japanese version differs from that of ours, where did u read this and can it be confirmed officially?
Wikipedia says otherwise and I can't find a reliable source that confirms that there are any differences.

Wikipedia is just what some supposedly 'educated' person wrote - No 'facts' there. The domestic Japanese iMiEV was available with either the standard pack which our North American cars all came with, or a smaller capacity SCiB pack which accepts rapid recharges of 100 amps or more better than the standard battery does, plus it lasts about 2.5 times as long when rapidly recharged in this manner. The smaller SCiB pack reduces range by quite a bit, but in Japan they have many quick charge stations where you can get a 75% recharge in 15 minutes or less

http://www.greencarcongress.com/2011/06/scib-20110617.html

Don

 

[DonDakin]

My 2 cents on L1 vs L2,

What don says is true about the health aspect for the battery.

Mixmike6 I think you will find that L1 can meet most of your needs but as winter gets colder more energy is needed for heat. L1 sometime is not enough if you get home late and need the car the next morning early. L2 is really handy for that. I think you will find with time that L2 opens more doors to how you can use the car in a similar fashion to L3 making long distance travel a possibility. It's just another tool.

I think you have a 2014 with the 12 amp L1 which you may be fine with. If so more power (small pun intended) to you.

Don.....

 

[Barbagris]

My 2 cents on L1 vs L2...

My 1 cent about L2 & L1:

In Japan and Europe we don't have L1. The car is designed thinking L2 as the way for charge the car.

 

[Don]

My 2 cents on L1 vs L2...

My 1 cent about L2 & L1:

In Japan and Europe we don't have L1. The car is designed thinking L2 as the way for charge the car.

I agree - I think you are exactly correct

The only reason North American cars even came with an L1 EVSE from the factory is because 1.) 120 volts is the common household voltage here (unfortunately) so most folks only have a 120 volt outlet in their garages, and 2.) They came with an 8 amp, 120 volt, L1 'trickle charger' EVSE only because older houses with poor wiring might not be safe to plug a 15 amp load into - They didn't want to run the risk of even a single household FIRE associated with the use of their electric vehicle . . . . THAT would quickly turn the public against EV's in general and certainly against whatever brand of EV was associated with the fire

Never using L2 is fine if your needs are met 'trickle charging' your battery, but when winter comes, the stock North American 8 amp EVSE is basically useless for preheating the car and winter preheating is pretty necessary for many of us to be comfortable driving an EV in the winter

Don

 

[mixmike6]

Thanks guys - I learned quite a bit today and Don good point on the preheating, hadn't thought about that.
I'll start using L2 once the winter comes in.

I was in Japan in July of 2013 and visited a Mitsubishi plant in Mizushima. I was informed that slight changes had to be made to the US/CAN version to meet North American requirements but that everything, including the battery, was exactly the same. So I dunno.
Fast chargers were everywhere in Japan and due to that they probably never heard of range anxiety.

 

[Don]

I was in Japan in July of 2013 and visited a Mitsubishi plant in Mizushima. I was informed that slight changes had to be made to the US/CAN version to meet North American requirements but that everything, including the battery, was exactly the same.

I think that's true, or at least it was early on - The iMiEV was sold there for years with the same 16 Kw battery we have before it was offered here. Later on, the cars sold in Japan were offered with a smaller, 10 KW SCiB battery which is much better when rapid charged several times a day. As you said, virtually no 'range anxiety' there, as they have quick chargers everywhere

The 'slight changes' you speak of for the North American version amounted to a completely new body, which is about 4 inches wider, about 4 inches taller and a foot longer than the domestic or European versions and then the airbag system was changed to meet US crash requirements

Don

 

[GdB]

... The regular i-MiEV battery is a standard lithium chemistry,...

is kind of an insult to the i-MiEV comparing it to cell phone and Leaf batteries.

My understanding is the i-MiEV has far superior batteries than the Nissan Leaf cell phone batteries.


Types of Lithium-ion Batteries – Battery University
http://batteryuniversity.com/learn/article/types_of_lithium_ion
Note in this article the i-MiEV is in a different category than the Leaf etc., but the stated LTO may be an error.

https://www.marklines.com/en/report/rep963_201104#r15
GS Yasua / Lithium Energy Japan
- Li-ion battery “LEV50”.
- Lithium vanadium phosphate battery.


http://pushevs.com/2015/11/04/gs-yuasas-improved-cells-lev50-vs-lev50n/
- "These new cells retain 80 % of the initial capacity after 5.500 charge/discharge cycles (100 % DOD @ 25°C)."
- "... A change of electrolyte that allows it to be more heat resistant, similar to what happened in the Leaf with the lizard battery. The Ragone curve (battery efficiency) also improved."
- "When buying a used i-MiEV, choose one that was built after the summer of 2012 to be sure that you get the newer cells with increased lifespan."

1. I looked at the data (translated from the pdf report), comparing the LEV50 and LEV50N and the performance difference is negligible and has a small affect on the maximum power level rarely reached with the i-MiEV, maximum acceleration

and DC quick charging which is 3C. In fact when I updated my range versus speed Excel file to include the GS Yasua LEV50 data, the range dropped 1 mile at 50 MPH, and 2 miles at 80 MPH. The new LEV50N has more of an effect at higher

than 3C power levels, with 4C and 6C data shown.

2. The article states it's a manufacturing cost saving change.

3. I suspect this change was a result of research supporting the Boeing 787 batteries, and not because of any problem with the i-MiEV LEV50 battery combination.



Assuming equal life for the LEV50 and LEV50N since no data is shown comparing life in the technical report, at 80% after 5500 cycles I was able to estimate battery degradation as a function of speed with my Excel spreadsheet, and the life

is excellent 80 MPH (1.77C discharge rate on average) 86% with the LEV50N.
What I am curious about is what motivated Mitsubishi to offer a 10 year 100,000 mile "no degradation" battery warranty without a huge Tesla capacity (spread the wear across more miles). They must have had supreme confidence... (
Also how many pennies did Nissan save with their 3 year batteries...)

See my Excel Spreadsheet results:
https://drive.google.com/file/d/0B2R9j5ABY2mLWlJhSzJ6eUZHdk0/view?usp=sharing

 

[Don]

What I am curious about is what motivated Mitsubishi to offer a 10 year 100,000 mile "no degradation" battery warranty without a huge Tesla capacity (spread the wear across more miles). They must have had supreme confidence...

We don't have a 'no degradation warranty' - When we bought our car new in May of 2012, the dealer has us sign memo of understanding of sorts that the battery warranty specifically excluded any loss of range, which was 'normal' and expected to be (but not guaranteed to be) on the order of 80% over the span of the warranty. Originally 8 years or 100,000 miles, it was later extended to 10 years I assume because the battery was performing better than they expected

The warranty covers a malfunction which makes the car basically inoperable, but if you experienced a degradation of say 30%, there is no guarantee that Mitsu would do anything for you - So long as the battery still charges and discharges normally, it's not 'malfunctioning - The car doesn't have it's original range anymore and THAT wasn't covered by the battery warranty

Don