Best method of long-term storage

[psyflyjohn]

We may be away for 1 to 2 months soon. I'm trying to figure-out the best way to store the IMiev while away. Dealers seem mixed or unknowledgable about the best method. I'm thinking the best way is to charge it up to about 80 or 90%, then disconnect the charger. Additionally, I would disconnect the 12 V. battery, which would continually draw-down the lithium if left connected.

Upon return, reattach the 12 V. (which should remain charged), and top-off the lithium battery.

What do you think?

 

[Don]

I believe that Mitsubishi says leaving it charged at only 30% to 40% is best for the battery pack for long term storage . . . . but I wouldn't consider 6 weeks to be 'long term storage'

The DC to DC converter is not powered on, recharging the 12 volt battery when the key is off (unless you are charging the car) so you should be good not disconnecting the 12 volt battery . . . . it won't run down the lithium pack and it should keep a charge fine for 6 weeks or more. If I was going to leave it in storage for 3 or 4 months, I probably would disconnect it though. Mitsubishi says to remove it and store it where it will not freeze when the car is put into 'long term storage'

Don

 

[mitsu5]

best temp around 75F do not expose to heat/direct sun if in hot part of the country. As Don mentioned charge should be lower than what you have now.

 

[alohart]

I will be storing my i-MiEV in my Honolulu condo parking garage parking space (in the shade but exposed to outside air) for about 6 months every year starting in April, 2014. Since 2009, I have been doing something similar in Sweden with my Honda Insight hybrid. It seems to recover well from its storage, so I plan to store my i-MiEV in a similar fashion but would like to ask for your advice, recommendations, suggestions, etc.

I plan to store my i-MiEV clean and waxed. I will store it with its battery pack at a 30-40% charge level. I will disconnect its 12 v. battery to prevent it from being totally discharged by the keyless entry transceiver, radio, and other small vampire loads. I will store it on jack stands to prevent its tires from flat-spotting and dry rotting (I might buy this jack and these jack stands). I will store it with the parking brake off to prevent the rear brakes from getting stuck due to rust. I will cover it with a car cover to prevent dust and salt accumulation on its paint and windows (I might buy this car cover).

When I take it out of storage, I will fully charge its battery pack. Will doing so also fully charge my 12 v. battery? If not, I will charge it separately. I will inflate its tires to 51 psi. Before lowering my car, I might take the opportunity to swap the tires right to left and vice-versa (waste of time or bad idea?).

Is there anything else that I should do?

 

[Don]

Sounds like you've about covered all the bases

Assuming the 12 volt battery has enough charge to start the car then just driving it will fully charge the battery pretty quickly. It should also recharge as you charge the traction battery though

Don

 

[PV1]

The 12 volt gets charged when charging the main battery, and when the car is READY. With lithium ion, you want to keep low SoC when storing, 30-40% like others have said. The brakes do rust easily. my i-MiEV wouldn't move after sitting two days in rain, they were rusted stuck.

I would also disconnect the 12 volt battery for anything more than a month unless you have a trickle charger or a 12 volt solar panel under 5 watts. The main lithium ion battery discharges very slowly when stored, barely enough to register a SoC difference. Disconnecting the 12 volt battery will cause you to lose radio presets, trip odometers, etc. Also, my car seems to default to a RR of 74 miles after disconnecting the 12 volt battery.

 

[peterdambier]

12v seems the big trouble maker to me.

There is no proof of selfdischarge for Lithium. They can be stored for very long time without loosing charge. If they discharge it is the BMS bleeding them.

Lead Acid does selfdischarge very rapidly.

Everything that stays alive when our i-MiEV sleeps is drawing from the 12v. So it is very reasonanble to either disconnect or better trickle charge.

Why do we need such a tiny 12v battery in the first place? And why is it Lead Acid?

From what I have gathered from other people and my own metering Karin's DC-DC is bleeding 1/3 kilowatt as soon as the car is "Ready" or the charger is running. That is in 3 hours I could not charge 9 kW but actually 10 kW and three hours driving bleeds one kilowatt hour to the 12v battery.

Cheers
Peter and Karin

 

[siai47]

The only problem I can see with long term storage with the 12 volt battery disconnected is some loss of data. And how important that data is, I'm not sure. There is some data stored in the BMS relating to the traction battery manufacturing date and usage over the life of the vehicle. If the 12 volt power is not supplied to the BMS for an extended period of time (I think it was 3 months) this data will be lost. This affects the range calculations for the dash mounted meter as the BMS adds the factors stored in the data table to make the calculations. I would try to keep the 12 volt battery charged and connected in storage if possible. If the car is stored outside away from a outlet to power a trickle charger, maybe the solution would be to install a small solar panel to keep it charged. I remember several years ago, Volkswagon shipped all of their new cars with a small panel attached inside the windshield with suctions cups to maintain the battery during delivery. I do know that I bought a wrecked I-MiEV a while back that must have exceeded 3 months without 12 volt battery power and the data in the BMS was still there so possibly it will be there for an extended period of time.