I am EXTREMELY lucky and still have a 5 year old factory battery that is running great
Why do you say that? I wouldn't think that is unusual at all, my 12v batteries last close to 10 years usually for me. The 2013 Cmax I never had any issues with it in 4 years life I had the car. My truck is 20 years old I've replaced the battery 2 times, and I don't use it that much. My wife's BMW also only once in the 16 years that we owned it. Sure capacity of the battery drains down over time so it can last less without the engine running, but if it can still start the engine when you get in then I'm still using it.
As far as the hybrid HVB, sure, its losing capacity as well as the Energi battery from the heat. However there are a couple of differences:
a) the hybrid battery is never full, it ranges from 35% to 70% SOC all the time, so batteries are that not full all the time live longer than ones that are full alot of the time. That's why you DON'T want to plug in the Cmax Energi every chance you get and let it sit at 100% until you use it. Plan better and only charge it to full shortly before you need to use the full charge. Otherwise charge it to 50% and use that if its enough. (short trip around town of 15 miles or less).
b) its not as evident to see that the hybrid battery has lost 20% capacity. You can check that by trying to get it as high of a SOC as you can, say 70% and then trying to go as far as you can in EV only and see how much KWH you can get out of it. Let's say you can use 0.5 kwh, then 20% less and you're going to be 0.4 kwh. So instead of going 2 miles you will be able to go 1.6 miles. In the Energi battery full is 5.5 kwh, if you lose 20% its going to be 4.4 kwh. If you could drive 22 miles on 5.5 kwh (assuming the same performance at 2 miles on 0.5kwh, then its going to be only about 17.6 miles at 4.4. You're going to notice that alot easier than 0.4 miles loss of range in the hybrid battery. You would be blind to think that the hybrid battery doesn't lose any range from heat, it does also, its just a much smaller battery to the range difference is much less obvious and even with a loss the car will still do pretty well in MPG because it will still switch off the engine for every stop and every downhill stretch.
Some people can drive 6.3 miles per kwh in the summer with the Energi. Its really a great car as far as efficiency, my wife just got a Mini Countryman SE and with that I can barely manage 5 miles per kwh, in fact about 4.9 is what I got tops. Due to that I can only go about 25 miles max per charge, even though it has the same size battery (they only rate it for 12 miles I did double that). However, something about the Energi makes it alot better, and its not weight...maybe its the Michelin tires?
Edited by rbort, 20 July 2018 - 05:21 AM.