I was kind a curious how sawman82 saw that
. Still am. Nevertheless ....
gwatpe said:
The PHEV from a battery life perspective may benefit if the capacity is maintained between 1/4 and 3/4 most of the time
Emphasis on "may". But even if it does, it is very hard to get the SOC below 25%, so without use of Save and / or Charge, you will spend more time with SOC between 1/4 and 3/4 than with extensive use of Save and/ or Charge.
gwatpe said:
My present PHEV battery health is still over 37Ah after 38000km and 9months. I suppose the mainly EV drivers will need to weigh up any petrol savings with battery replacement costs
First of all, anybody who wanted to burn fuel in order to prevent wear and tear of the drive battery should have bought a petrol car. No wear or tear on the drive battery whatsoever.
Second, one car is a very very small testset to base conclusions on. Most if not all other readings we see are from the Northern hemisphere, i.e. a totally different climate. And maybe slightly different specs?
Third, whether you use Charge and / or Save on long stretches without external charging or not hardly impacts how much power goes out of / goes into your battery. That would only be if you could stop the engine from recharging the battery, while driving in serial or parallel hybride mode.
Personally, I take this in consideration (like gwatpe, I keep repeating myself, but for the sake of newcomers ... :mrgreen: ):
Charge rate drops when SOC rises above 50%. And some more when SOC rises even higher. Take this sample calculation (not unrealistic, IMHO):
Under good conditions, at 100 km/h, you need about 15 kW to maintain speed.
At 100 km/h, charge rate is approx. 10 kW when SOC is below 50%.
At 100 km/h, charge rate is approx. 8 kW when SOC is above 50%.
At lower SOC, in one hour of parallel driving you do 100 km on petrol, and gather enough battery power to drive 10 / 15 * 100 = 67 km EV.
At higher SOC, in one hour of parallel driving you do 100 km on petrol, and gather enough battery power to drive 8 / 15 * 100 = 53 km EV.
So, the same number of revolutions of the engine will take you 167 km when driving around with lower SOC and 153 km when driving around with higher SOC. And that number will drop further when you keep SOC even higher. Utilmately, if you were able to keep SOC at 100%, the charge current would be 0 and you would be driving a very heavy petrol car.
Of course, fuel consumption during hybrid drive will be higher at lower SOC than at higher SOC, but that is easily compensated by the increased "EV range gain". If not, they would have never invented a Prius.
