There is no link or documentation for it, its just my experience with batteries for years and knowledge of the subject in general that makes me come to those conclusions.
-=>Raja.
I ask for platform specific documentation because if what you are claiming is the bonafide truth, then wouldn't Ford advise us of this, much in the same way that they advise about other maintenance items, like oil changes and general maintenance?
I have a body of experience myself, and that is having nearly 11 years of Prius ownership and a whole lot of reading and digesting of material prior to that purchase and then afterwards when I was in the honeymoon period of first-time hybrid ownership.
Here is my takeaway from that experience. The Prius has a Ni-MH battery, not Li-ion. When the Gen2 Prius was introduced Li-ion batteries necessary for the scale and size needed for even a partially electrified vehicle weren't practical. Ni-MH suffers from memory effect. The only reason I know this is because I have purchased and used many Ni-MH rechargeable batteries for household use and have experienced memory effect first hand, along with everyone else that has ever purchased and used rechargeable batteries.
So, a huge concern of the early Prius adopters was battery life. Toyota had thought that one through. The sweet spot for reducing, or possibly eliminating, memory effect with Ni-MH batteries is to never fully charge them and never fully discharge them. Ok, cool. But how high is too high for charging and how low is too low for discharging. Based upon the material I have had access to, in general, the Prius battery is not charged beyond 80% of its potential maximum capacity and is never discharged below 60% of its potential maximum capacity. So, the battery operates in a rather narrow 20-point range between 60% and 80% of capacity. Additionally, the battery representation on the dash did show a battery that could be fully charged and fully discharged, however that was only a representation. The battery icon on the dash was really showing a fully battery at 80% charge and an empty battery at 60% charge. Additionally there is a computer on board the Prius that does nothing but battery management, monitoring charge levels and battery temperature and then communicating those values to the central computer so it can make judgements and adjustments in how the vehicle behaves, managing cooling fans, etc., to help maintain the battery.
I share all of this for a couple of reasons: 1. To show that the auto manufacturer is really more in control of the behind the scenes behavior of a vehicle, and 2. to illustrate that what we are presented on the dash of our vehicles might not reflect absolute reality. I also write this to demonstrate that if battery life were actually something we could directly control in our Energi vehicles, we would have received documentation along the same lines as a maintenance schedule, to follow.
As it currently stands, hybrid vehicles, conventional or plug-in, regardless of manufacturer, wouldn't be a success if consumers were having to monitor and maintain their high voltage batteries as a course of their daily vehicle usage by going out of their way to drive a certain way, take certain more efficient or less efficient routes between places, by using or not using the EV only mode, plugging them in only a certain times and then going out in the middle of the night to unplug them, etc. A really well designed vehicle will run as the manufacturer intends with a minimum of maintenance. In our day and age, oil changes and replacement of wear parts, like tires, brakes, shocks and struts, starter batteries, spark plugs, filters, and windshield wipers are about the only things we have to do to keep our vehicles running well for a very long time.
Anyway, do as you wish, but I can't advise new owners to do things which I know aren't material to the long term performance of their vehicles. As it stands right now, I have no concrete material which would suggest that Ford isn't employing some level of battery management or that they haven't tested the high capacity Li-ion battery extensively prior to releasing this vehicle in the wild. I also do not know if Ford is using the full capacity of the battery or if their battery management routines include a similar structure as to what Toyota developed many years ago.
Anyone provide me greater information about how Ford handles battery management and then I might come to a different conclusion, but until then I keep it simple. I charge the car up when I can. I keep the vehicle plugged in while at home. If my trip requires that I deplete the EV portion of the battery and drive conventional hybrid, I do so. In the end, this vehicle will wear out and I'll have to go looking for another, so I accept that wear and tear is part of the ownership process and that battery life is a wear and tear item.
To the OP, go out and enjoy your vehicle. Charge it up fully when the opportunity is convenient, use all your EV power when necessary, leave the car plugged in while at home, and just don't over think the vehicle.
