Is it safe to keep battery at 100% SoC?

[DivineComedian]

As an ex Nissan LEAF owner, I'm a bit wary of keeping my MY16 Outlander charged to 100% for longish periods of time. This was a complete no-no for the LEAF, which is why lots of LEAF owners either charge to 80%, or time their 100% charging so that it finishes just before they need to drive the car.

Do I need to worry about this for my Outlander? Is the PHEV indicated 100% a 'real' 100% or does the battery management system hide enough capacity at the top end so that 100% on the dash is actually fine for the car to sit with for a long time?

 

[jaapv]

Not a known issue.

 

[gwatpe]

The voltages returned at the end of a full charge on the cord, by the OBD port for the battery cells are typical for a Fully Charged Lithium Ion battery. Does not appear to be any margin of under charging say to only 90%.

 

[Vince31]

I use LiPo batteries a lot for my hobby and its good practice not to leave a battery for long periods at 100% charge. Long periods means storage etc, where they should be stored at about 80% charge, however regular use from 100% should be completely fine.

 

[zzcoopej]

or time their 100% charging so that it finishes just before they need to drive the car.

Not directly related to your question, however a few of us have found that you get about 5% more km if you drive your car straight away after charging, as the SOC drops from about 104% to something like 97% after a few days (remember 22.5% is the "normal" minimum).

 

[Sunder]

Do I need to worry about this for my Outlander? Is the PHEV indicated 100% a 'real' 100% or does the battery management system hide enough capacity at the top end so that 100% on the dash is actually fine for the car to sit with for a long time?

The battery has a real 12kwh capacity, but few people ever get more than 10kwh out of it, so I'm guessing that it's keeping it from being charged to 100%, or discharged to 0%.

Someone with the charge app or otherwise reading the right OBD-II codes will be able to confirm.

The "best" storage conditions for most forms of 4.2v Lithium batteries is to keep it just above freezing and kept as low voltage as possible but above 3.0v per cell. Since all batteries have self discharge, common practice is to keep them at 3.6-3.7v so that you only need a top up every few months.

 

[anko]

SOC is expressed in a percentage, calculated as "actually stored Ah" / "maximum storable Ah". Usually is ranges between 100% (full charge) to 30.5% (at higher speeds) or 26.5% (at lower speeds). When driving demands dictate SOC can go as low as 13%, but by that time heater and A/C will have been turned off and available power will have been reduced.

"maximum storable Ah" (a.k.a. battery health) is a calculated / measured number that apparently is a little pessimistic at some times. Because of this SOC can be > 100%

 

[maby]

Do I need to worry about this for my Outlander? Is the PHEV indicated 100% a 'real' 100% or does the battery management system hide enough capacity at the top end so that 100% on the dash is actually fine for the car to sit with for a long time?

The battery has a real 12kwh capacity, but few people ever get more than 10kwh out of it, so I'm guessing that it's keeping it from being charged to 100%, or discharged to 0%.

Someone with the charge app or otherwise reading the right OBD-II codes will be able to confirm.

The "best" storage conditions for most forms of 4.2v Lithium batteries is to keep it just above freezing and kept as low voltage as possible but above 3.0v per cell. Since all batteries have self discharge, common practice is to keep them at 3.6-3.7v so that you only need a top up every few months.

That's interesting - any idea how that translates to a reading on the PHEV battery gauge?

 

[Grigou]

As an ex Nissan LEAF owner, I'm a bit wary of keeping my MY16 Outlander charged to 100% for longish periods of time. This was a complete no-no for the LEAF, which is why lots of LEAF owners either charge to 80%, or time their 100% charging so that it finishes just before they need to drive the car.

Do I need to worry about this for my Outlander? Is the PHEV indicated 100% a 'real' 100% or does the battery management system hide enough capacity at the top end so that 100% on the dash is actually fine for the car to sit with for a long time?

The answer is in your owner's manual : avoid to keep the battery charged at 100 % during a long time.

But what is a "long time" ? For me, it's just an addition of "short" (or less short) durations, and the target is to minimize all these durations ...
So these LEAF owners are right

 

[Sunder]

That's interesting - any idea how that translates to a reading on the PHEV battery gauge?

The Mitsubishi bar seems to report SOC rather than voltage, so that would mean that 3.6 to 3.7v should be about 50-60% on the bar.

The reason 3.6 to 3.7v is chosen, is that it's the lowest voltage that still has a fair bit of capacity left. At 3.5v you;re looking at around 20% capacity left.