[chentro]

Hello everyone,

I need to store my 451 ED in a Southern CA Desert garage for 2 months (April and May). Any recommendations on what the SOC should be and should I have someone attend to the car in those 2 months.

Thanks for the info

 

[SuperSmartie]

In general, worry more about the 12V than the 400V battery: if the little one goes flat, it can be tricky to revive the car. Either plug the car in during longer storage, or get a battery minder for the 12V and plug that in.
If the garage is exposed (i.e. it gets hot in that desert) definitely plug the car in so the airconditioner can keep the battery cool.

 

[Blaine]

SOC on lithium ion batteries should be roughly 40-60% for storage. Similar to how your new phone arrived from the factory

As SuperSmartie said, keep the 12v happy. Put a battery tender on it.

That said, I've left our ED for three weeks unattended with no apparent impacts.

 

[Yinzer]

In general, worry more about the 12V than the 400V battery: if the little one goes flat, it can be tricky to revive the car. If the garage is exposed (i.e. it gets hot in that desert) definitely plug the car in so the airconditioner can keep the battery cool.

Two comments.

1. What problems have occurred if the 12V battery goes flat? The one time it happened to me (left the parking lights on) I charged it with small 12V charger and everything was fine. Pulling up the carpet and that foam floorboard thingy is a pain though.

2. The downside of leaving it plugged in is that while it might cool the pack at over 40C (the manual does not make it clear that it does this, though) is that it will be maintained at 100% SOC which is not so good.

 

[SuperSmartie]

Actually, it does say the bit about plugging in to cool the battery in the manual. Haven't tested if it actually does for lack of appropriate weather here in the Northeast.

True, keeping the battery at 100% is not ideal, but overheating it is significantly worse. If I could choose between the two, I'd keep it cool.

Keep in mind that the car doesn't float the battery continuously like a lot of consumer electronics do, but turns the charger off completely once that battery is full, and doesn't turn it on again until charge has dropped a few % points. I suspect during the OP's two months it won't be that often. I occasionally park mine for a week when I'm traveling, and it never enables the charger again during that time. But I haven't had the patience to leave it until it does to see how long that takes. I just can't be without my smart for that long!

Come to think of it, except for the potential heat issue, 2 months is a really short time, so it doesn't really matter what the charge is.

 

[Yinzer]

Yeah, the manual states: "If the vehicle is not connected to a voltage
supply, it must remain within a temperature range from -4 F (-20 C) to 104F
(40C) ." That implies that it automatically cools as well as heats.

BTW, self-discharge of lithium batteries is nil. So the charger probably will never go on even if stored for a year - unless the pack heating or cooling comes on. The 12V battery will probably discharge though.

 

[SuperSmartie]

The 12V battery will probably discharge though.

Hence my initial response to the OP.

 

[Yinzer]

Hence my initial response to the OP.

Probably not over just two months. I've left cars sit for 3-4 months and they started just fine. Maybe the Smart has a higher quiescent current draw from the battery but then it also does not have to turn a starter motor.

One thing for sure, having flattened the battery once in my ED, it would be nice if Smart provided charging connections under the hood for charging/jumping the 12V battery - such. Pulling the carpet and floorboard piece up to get at the battery is a pain. If I owned my smart I'd rig up such a thing.