Future Battery Replacement - A Better Battery?

[DonDakin]

That is very interesting malm. Thank you for the video.

You may have hit 2.75 when demanding power and then rebounded back up to 3.25 with no current demand.

So that means that you can turtle around for 10.5 % of the battery. If driving very slowly that's about 15 km on a new imiev. Not bad for a reserve. I'm surprised that they let it go that low.

Maybe the turtle means "drive slow or you will soon have to push" more like a reminder then a lower power mode....


Thanks again for the video...

Don....

 

[Malm]

No , I don't think so. How many times I went to turtle in one year, but only in march, 1, the day of his birthday, recalibration happened.

 

[DonDakin]

Hey pv1

It would be nice if the bms recallibrated. I seem to recall that mitsubishi recommends to drain the battery to 2 bars or below and then fully charge every 2 months. This kind of implies that the bms can learn capacity by counting ah and looking at voltage. I wonder if it would freak out if it saw a growing battery.

I think malms battery charges to 100 % even thought it has lost capacity. But I'm not sure about that. If this did happen then the gauge would always read 100 % when full and you would not loose bars. But to tell the truth that would be a mixed blessing. You could always estimate capacity loss by looking at the RR but driving habit comes into play there.

I don't think anyone on this forum has "lost a bar" yet as the leafs do. But I think Dave's car lost lots of them when his battery was failing so I guess the capacity is hardcoded in the bms. It would require hacking to get the gauge to be true.

This sounds like an experiment for a crashed imiev that still has a decent battery. I just wish I has more time to play with something like this.....

Don......

 

[Malm]

That is very interesting malm. Thank you for the video.

You may have hit 2.75 when demanding power and then rebounded back up to 3.25 with no current demand.

So that means that you can turtle around for 10.5 % of the battery. If driving very slowly that's about 15 km on a new imiev. Not bad for a reserve. I'm surprised that they let it go that low.

Maybe the turtle means "drive slow or you will soon have to push" more like a reminder then a lower power mode....


Thanks again for the video...

Don....

Wrong. Never gone below 3,25 V. Allways looking by Canion. NEVER below 3,25 V. I'm sure, Stops because the 12,75 kWh are consumed and now that is 100% of SoC. It stops because it went to 0,0% of SoC. Remember, it is no more of 16 kWh, is of 12,75 kWh and he knows that (finally). But for me, it calculated its capacity wrong, maybe 14 kWh should be correct. Now i will have to wait one year for it to recalculate it again. Maybe with 12,75 kWh in two years it would get it right.

Wrong again. Turtle means stop. When an i-MiEV lost 8% of capacity, they will be lost on the turtle, and you will be able to do only 4 km with turtle, maximum. NONE of you will be able to drive 10 km with turtle if you have it for some time (1 year).

I think i will remove the video, because i don´t want to be responsable for anyone to stop away from home.

 

[Malm]

My i-MiEV in february stoped at 14,5% of SoC. Stopped with one bar on the gauge. So, its like I losed one or two bars. As simple as that. You don´t have to use your imagination, you just have to read what I say. If you drive nonstop from 100%, 16 bars, to turtle, you will find your degradation, as simple as that. Just read and believe me.

 

[PV1]

Don, I think with a failing battery, one of the cells hits HVC (high voltage cutoff) before the rest of the pack gets near full. When that happens, the car stops charging at whatever SoC it was at. It'll try to bring it inline via balancing, but as the cell suffers more damage from its defect, it loses even more capacity, further reducing possible SoC. So bars get lost for a sudden decrease in capacity, but not a gradual loss, since no cell hits HVC before being close to full.

That's why I think starting with a new pack discharged and the i-MiEV's computer at a low SoC, you might be able to retrain the car for a bigger battery. My car hits 100% when charging and keeps going for a while. I've noticed now, 5 months later, it spends less time charging at 100%. So at the top, it appears to be voltage-based while balancing. This may be the key to a larger battery.

 

[DonDakin]

Hey PV1,

Thanks for the info. I have played around with 18650 cells for an electric bike and Your right as the capacity goes down the voltage goes up quicker on charge. That's inline with your explanation.

I wonder if if would be possible to charge and put an unsensed load on the traction pack during charging. If you could bleed off some of the current then you could perhaps see if the charger would keep going until it top balanced all the cells. You would need to bleed the battery without the ah counter knowing. I guess if you could get access to the battery during charge it may be possible to try this. It's more of a bench test idea then something you could practically do on the car.

As an aside I was wondering if it would be possible to charge faster with the built in 3.3 KW charger if you injected power into the 12 volt system ? From looking at Canion it seems to me that all 12 V loads (computer/pump/EV gizmo #12) take away from the energy going into the battery. Sooooo if you were to make those loads lighter by say adding an isolated 12 V power source that's just above the dc-dc converter voltage during charge would you get a faster charge to the traction pack ? I'm thinking you might get another 400 Watts in there dropping charge time ~10%.

What do you think ?

Don....

 

[PV1]

Checking with OVMS, 12 volt system voltage while charging is 14.4 volts, so if you get about 14.6 volts into the system, that should take the load off of the DC-DC converter.

Putting an unmeasured load on the battery while charging would require removing the battery from the car and working inside the pack while having it hooked to the car. The battery current is measured inside the pack before heading back to the drive inverter.

Interesting idea, though.

 

[siai47]

The key to a lot of this stuff is how the BMS gets information about the status of the pack. As was pointed out in the last post, the BMS can only detect what is happening with the vehicle mounted pack. If you add an external pack and put it in parallel with the vehicle pack, the BMS still only sees the internal pack. The SOC reports only the internal pack condition as it is not seeing the external power being supplied to the vehicle during operation, nor is it seeing charging current going to the external pack during regeneration (or normal charging). What it is seeing is a I-MiEV that is hyper-mileing like crazy by using half the expected energy. This seems to affect the RR meter as it keeps increasing over time. However, the BMS also has hard coded into it the new capacity of the pack along with a time and mileage calculation for assumed degradation over time. I guess the point is, if you increase the capacity of the "battery" by added external power to it, the RR may be way off but the SOC tick marks on the dash still will give you a accurate representation of the remaining power in the vehicle.

As far as battery health is concerned, anyone who owns a I-MiEV needs to have the CANION app. It is hard to believe how long it takes to balance a pack that is even slightly out of balance. Without CANION you have no clue. Unless you charge to 100% on a normal basis for an extended period of time, you will not get the pack in balance. When I put a different pack in my I-MiEV, the replacement pack was out of balance on three cells. Watching the charging process shows that no balancing takes place until the charger tapers off it's output. This starts to occur around 98% SOC. However, when the first cell hits 4.11 volts, charge current is really dropped and balance process continues for a short period of time before the charging stops. It took almost a thousand miles of driving and many, many charges from a fairly high SOC to 100% to bring those three cells back in balance. Now that the pack is in balance, the RR is consistently higher then it was when I started. I know it is supposed to be "bad" for the battery to go to a high state of charge. However, the real fact is it is bad to store it at a high state of charge, therefore driving after completing the charge shouldn't cause a problem. I think it is much worse to have a pack that is out of balance. Once it gets back in balance, the internal balancers do a pretty good job as long as you go to 100% charge once in awhile.

 

[kiwimiev]

The CAM80 from EVTV looks like it may replace the LEV50 making a 25kW battery pack.
Has anyone tried to fit them?

http://store.evtv.me/proddetail.php?prod=CAM80FI

 

[jray3]

The CAM80 from EVTV looks like it may replace the LEV50 making a 25kW battery pack.

Wow- the specs just keep getting better and better, though it looks like CALB is trying to reset pricing levels, and Jack's never one to undercut the market unless he can still make out like a bandit. Buddy pairs of those cells could feed a Zilla 1k quite nicely, but salvaged LEAF cells still look like a better buy. I'm not even monitoring the options for i-MiEV cell replacement, since the universe of options should be very different when that time comes. Unshackling the 49 kW limit on our drivetrain would be more appealing to me (which would then drive interest in a replacement pack after I murder the stock cells or simply want more range).

 

[alohart]

The CAM80 from EVTV looks like it may replace the LEV50 making a 25kW battery pack.
Has anyone tried to fit them?

Wouldn't the CAM80's different chemistry (i.e., different voltage range) and different capacity make it a difficult replacement for the LEV50? I would think the entire BMS would need to be changed.

 

[kiwimiev]

The CAM80 from EVTV looks like it may replace the LEV50 making a 25kW battery pack.
Has anyone tried to fit them?

Wouldn't the CAM80's different chemistry (i.e., different voltage range) and different capacity make it a difficult replacement for the LEV50? I would think the entire BMS would need to be changed.

The BMS and charging are probably okay...the LEV50 LiMN max charge voltage is 4V while the CAM80 is 3.7V but other LiFE batteries like Thunder Sky can go to 4V and the CAM80 has overcharging tolerance. The minimum voltage for both is 2.5V
The capacity difference doesn't affect the BMS and charger...the car just runs longer and takes longer to charge.
I would be more concerned about the price...$155 each = $13640 for the pack!!

 

[DogMan12]

I'm not even monitoring the options for i-MiEV cell replacement, since the universe of options should be very different when that time comes.

In fact, I worry that Mitsu N.A. will even exist. Since everything on this car seems finely balanced and inter-engineered, the idea of not having a Mitsu-approved replacement battery seems a dicey proposition.

Some of you electro-garage wizards might build a better performing car with different components. I, however, am just a guy who wants to support non-fossil mobility and with a car like this - it goes to the dealer for any real work. (Yes, they have been undersupported by Mitsu N.A., too.)

How about a futures contract for an OEM replacement batt? Riiight.

 

[DogMan12]

I emailed MMNA:

Subject: Assurance Of MiEV Battery Availability

Greetings,

I am a happy owner of a 2012 MiEV.
One of my only worries about this car is that given the low sales volume, will I be able to obtain a replacement battery when needed? This will likely be in 2021 or 2022.
What assurance can Mitsubishi N.A. provide me as a Mitsubishi owner that this critical part will be available when I need it?
Thank you!

Walla Walla, WA

MiEV VIN JA3215H18CU028527

Here is their reply:

Thanks you for your email inquiry.

As you are aware, we just released the 2014 iMEV and we are required to carry parts for the duration of the warranty period for the component in question, which in the case of the traction battery, is 8 years.

We can only speculate on the availability of the battery after that point in time. Assuming the iMIEV continues to be distributed in the U.S. (which we cannot confirm at this time) battery availability will overlap with warranty coverage.

Thanks again for giving us the opportunity to respond to your question.

The information contained in this reply email is in response to your email sent to MMNA with the information provided by you. To the best of MMNA’s knowledge, the above response is accurate and correct, however MMNA reserves the right to amend or correct any of the above mentioned response.

 

[DogMan12]

So all, what ARE we going to do when our batts are done?

What makes sense financially, if anything?

Is it even remotely possible that MiEV owners could band together to "group buy" some custom order packs from some independent shop?

 

[jray3]

I believe that it will be possible to rebuild our packs even without Mitsu support, one reason I picked the car was the use of only 88 large format cells that are bolted together, something I'm confident I could rebuild myself.
Owners of the original Honda Insight have a couple of pack rebuilding options available. I could see a couple of list members forming the core of such an effort by providing the battery trays from salvaged cars to serve as 'rebuildable cores'.

Here are examples of EV pack building/rebuilding entrepreneurs, some providing rebuilds, others just a how-to guide. I have personal experience with and could recommend the first few.

http://www.hightechsystemsllc.com/pt_Batterypacks.html
Derek is the leading builder of racing packs, but it would take some work to ensure compatibility with our cars' BMS

http://www.manzanitamicro.com/
Rich and Co. have done several 'orphan pack' rebuilds.

http://www.autobeyours.com/MASP%20autobeyours%20as%20a%20tenant.htm
Steve is an incredibly entrepreneurial Prius rebuilder, he finished off an incomplete Azure Dynamics/ Ford Transit Connect Electric as his shop truck.

Here's a quick weeding of google results, some may be vaporware.
http://www.batterymd.com/electricservices.html
http://www.evcenters.net/services.html
http://www.priusrebuilders.com/
http://www.hybridbatteryrebuild.com/
http://www.hybridrevolt.com/catalog/
http://www.hybridbatteryrepair.net/ (these guys abandoned the Insight market)
http://greentecauto.com/about-us
http://hs.thehybridshop.com/conditioning-quote

 

[PV1]

I wonder if we could get Tesla cells and build them into bricks the same size as LEV50 cells. The same voltage characteristics should mean compatibility with our BMS, though the trick is to get the car to recognize an increase in capacity, which could be as simple as installing the cells at a low charge and switch the pack with the car at a low charge level. If calculated SoC hits full before the voltage gets up to 4 volts/cell, the car may continue a slow charge to the voltage limit.

It is my guess that the balance phase at full charge is done every time the car is charged to synchronize 100% SoC with HVC (High Voltage Cutoff). My phone seems to function that way. I switched to a different charger, one that shuts off when current drops to a minimum. What that was doing was shutting off before the phone was done, usually stopping at 98-99%. In a relatively short period of time, the battery ended up drifting 43%. When the phone said 100%, cell voltage was only 3.8 instead of 4.3. On the normal charger, the phone went to 100% and continued charging at full speed for about 5-10 minutes, then stopped. After a hard reset, the phone deleted its battery info and either reverted to the factory battery map or guessed SoC by voltage. It charged until the battery hit HVC and set that as 100%. If we could figure out how to "reset" the i-MiEV's SoC clock, we might be able to increase the available capacity of a rebuilt battery pack.

 

[jray3]

I wonder if we could get Tesla cells and build them into bricks the same size as LEV50 cells.

Mike Phillips is another one of those owner/entrepreneurs who's keeping a whole line of orphan vehicles alive by turning his hobby into a business supporting old US Electricar models. He has experimented with making replacements of funky-sized batteries with 18650 cells.
http://rotordesign.com/blog/lithium-pack-plans-for-u-s-electricar-vehicles/

He's now making larger packs out of 18650 cells.
http://rotordesign.com/blog/18650-lithium-module-update-160-cell-cad-design/

 

[iwatson]

This thread is an interesting read. I think an available replacement pack shouldn't be a problem if you have the cash to spend. The bigger problem will be putting an expensive battery into a 10 or 15 year old MIEV.

I bought the car because it was cheap, not because it was the finest EV on the market. We got a barely used one for $10,500 +Tax.

My wife loves it but, facing facts, its a cheap little basic economy car. The only reason it had such a high sticker price is because it has a $20,000 battery in it. Surely over 10 to 15 years the seats and interior appointments will show wear to the point that we'll be ready for something newer. Plus the suspension is likely very basic, so 10 to 15 years from now it may be very costly to maintain and replace suspension parts.

Meanwhile battery tech, new models and designs, will most likely mean that in 10 to 15 years we can move on to an EV that's much better designed, with much better range and style.

Because it already has a very unusual appearance, it will also likely look very dated, 10 to 15 years from now.

Of course, the industry could go the other way. With low gas prices --- In 10 to 15 years we could remember the years of 2011-2016 as the days when car makers dabbled in Electric cars. If that scenario were to play out then, yes, we'll be looking for ways to keep our antique EV's going by adding replacement batteries.