First of all let me start out by saying that those are my practices and opinions, you might have other thoughts or ideas and that may work for you, I wanted to share mine.
1) Do not leave the car plugged in all the time. In fact, best to go with "full on departure" practice whenever possible.
What does this mean? Well, for starters don't leave the car plugged in day and night. If you know you're going to leave tomorrow early morning, then plug in the car before you go to bed. If you're going to leave tomorrow around noontime, then plug in the car when you wake up.
2) Recharge only when necessary as opposed to always.
Instead of using the car for a 3 mile trip to the store and back and plugging it back in, try to use the car for several 3 mile trips to the store before you recharge it. This will lessen the charge/discharge cycles which are finite in any given battery pack. If you can make 3 round trips on a full charge before recharging, its better than recharging after each small trip.
3) Keep the discharge current low and manageable for the pack.
Higher discharge causes more heat and stress on the battery. Limit your EV driving to 2 bars tops in the Empower screen. Instead of driving down the highway at 70 mph in EV mode and draining the entire pack in 15 minutes, slow down to 50 if you need to be on the highway and let it take longer to drain down, or, use the secondary roads of speeds of less than 50 mph when you're driving in EV mode. Even at 65mph on the highway in EV mode, the drain is severe on the pack when faced with some hill to climb. Watch the % of the battery screen, going up a hill it could drop 1% every five of seconds..
4) Do not drain the pack all the way down to nothing unnecessarily.
If you have to use all the pack, try to shoot for getting to your destination with 0% HVB but a full hybrid battery. This means that as you turn down your street you should be just switching over to the hybrid battery. Digging into the hybrid battery too deep (less than 1/2 full) causes more stress on the cells and that's where they will drift apart the most and need to be rebalanced. Rebalancing happens with every charge cycle anyways, but high discharge current (see 3 above) or deep discharge will cause a more severe out of balance situation. The only exception to this is that if you're trying to stretch it home without starting the engine for the entire trip, then if there is a chance to make it on EV power go for it with EV+, otherwise if the engine is already hot from a longer trip, don't be afraid to crank it a few more seconds to save the HVB from further discharge.
5) When you arrive home, if the pack has been drained and its hot, do not plug in the car to charge right away. Give the battery some rest time to cool down if possible. This is especially true if its hot outside (summertime) and/or if you're been driving on the highway in EV mode and/or you've drained most of the pack. This doesn't apply in the winter as the cold will insulate the battery pack from heat and negate this safety factor. Remember that heat damages the high voltage battery, not the cold. Plugging in the battery to charge causes the battery to maintain its hot temperature due to charging, yes there is a fan to try to counter this effect, but its best to let the battery rest before trying to recharge it as prolonged exposure to hot temperatures is bad for the battery.
6) If at all possible, always park this car in a garage out of the elements. Severe heat is bad for battery, especially being left outside to soak in the sun day after day in the summertime. Cold impacts range on the battery and also makes the drivetrain stiffer -- being protected in a warmer garage, even 10 degrees warmer than outside helps during the winter.
7) When storing the car, whether for 2 days or 7 days or a month, recharge the battery pack back to storage charge level of 60%, +/- 10% is OK. This accomplishes two things...a) Li-ion batteries like to be stored long term at this charge level, and b) the battery at 60% is within range of 100% if you need it on short notice even with the stock 110v charger. In other words, let's say you take a trip today and come home with 10% battery. Plug the car in and bring it back up to 60% before you go to bed and then unplug it if you're not sure you're going to use the car tomorrow. If you know you need the car tomorrow first thing in the morning, plug the car in instead before going to bed so it will be ready on departure. However, let's say its the weekend and you don't need it, leave it at 60% Friday night. Saturday you might not need it, but if you wake up and realize you need to go somewhere and need 100% as its a ways away, then when you wake up in the AM, 100% is only about 2 hours away whereas 10% would have been 5 hours away to be ready to go.
Doing all those things in my opinion will make some difference in the battery life, not today, not tomorrow, but 2 + years from now. Treating the battery harshly does not show up right away, but each "damage" you do (any to all of the 7 points above) to the battery is additive over time so its best to keep those as few and far between as possible.
You habits can make a difference and I hope that you get many happy EV miles from your Maxie!
Edited by rbort, 04 April 2015 - 08:45 PM.