Question re Hymotion upgrade

A strange thing happens when you keep the SOC around %80. The Prius will try to bleed off the extra energy to get its self back to %60 SOC. So with the extra Hymotion battery keeping the SOC at around %80 for a longer time the Prius will use the electric motor more to bleed off the extra energy. It will use it more at low speeds as in EV mode and at high speeds as in electric assist mode. This electric assist can give you 100+mpg at highways speeds for the length of the charge. In the case of the Hymotion pack about 30 miles. After the pack has been drained your Prius will act like normal keeping a %60 SOC most of the time. The Hymotion pack will not let you EV at 55mph or anything out of the ordinary Prius operation.

 

This much older thread went through a lot of the details on how this might work out:

http://priuschat.com/forums/prius-hybrid-news/31668-3-500-tax-credit-plug-upgrade.html

The best reference point I can find remains CalCars, who claim 85-mpg-equivalent from their conversion. That is, the total fuel cost (electricity plus gasoline) was the same as a (then) 85 mpg gas-only car. Presumably, due to the runup in gas prices, it would now be higher. I calculated at that time that the CalCars figure implied a roughly 50/50 energy mix in their driving -- ie, half their miles were electric, so to speak.

But clearly, this is going to depend a lot on trip length, trip speed, acceleration requirements, and ambient temperature (how will you warm the cabin in winter without running the ICE?). For me, most of the miles we put on the Prius are low-speed low-acceleration short-trip miles, so I'm thinking that most days we'd never have to turn on the ICE. (We can suppress initial warmup with the EV switch).

The thread discusses other fine points, basically explaining why the conversion is not as efficient as you might expect it to be. That said, I've put my deposit down anyway.

 

30 miles? all that money and it is only helpful for 30 miles?

Too expensive for far too little benefit. IMHO of course.

 

The 30-40 miles should be the straight EV mode range. At higher speeds the high mpg assist mode should last up to 2x this.

I know it doesn't sound like much, but keep in mind the US average is about 33 miles per day (12,000 miles per year). If you can get 100mpg for 50 or so miles a day, how often would you really have to revert to "only" getting 50 mpg? It doesn't help with your fuel cost for long trips, but in general would take a big chunk out of most peoples annual gasoline consumption.

Rob

 

The mileage is rated at ~150mpg for short trips, ~100mpg for slightly longer ones (15-25miles?).
The benifits are definately more for city based driving.
If you hopped on an interstate and drove the tank dry I am sure the mpg would come down to 60mpg.
As I am a city driver it is a huge benifit YRMV

 

Not according to this Argonne National Lab test. It got 25 mile range for city and 31 miles for highway under Charge Depleting mode. It is important to note that the usable energy they got is 3.1 to 3.4 kWh.

 

to what degree a 30 mile EV range would help anyone all depends on their situation.

in mine, my entire commute would be in EV (well it is now with the Zenn) and if anyone is in that situation or one where it help a majority of their commute, then it would be a big benefit.

the difference in cost between my Pri and the Zenn is currently 4 to 4½ cents per mile. granted electricity may go up (Puget Sound Energy has a rate hike request pending to take effect June 1) but it will be slower and more predictable. but as well all know, gas prices have gone crazy and i dont think we are not anywhere near done with the price increases. i expect it to plateau around $4.25 to 4.50 a gallon. that could bring the basic cost of Prius operation up to as much as 8 to 8.5 cents per gallon or 6 cents more than my Zenn.

now my Zenn's performance maybe be different than the Pri's plug in performance but i doubt that it would be that much different. it runs just over 2 cents per mile. i would use 2½ cents per mile for calculation purposes since the rate hike request if not approved this time will be approved next quarter (i dont ever remember them being turned down more than two times in a row and they did not ask for a rate hike the two previous quarters) plus it seems that most EV's of all types seem to do about 3 miles per kilowatt

at 5 cents per mile (after considering additional expenses for electricity. my rates are probably lower than average so keep that in mind) over say 30 miles per day over say 250 commuting days (overlapping shifts would have us driving 6 days a week so could be slightly more)

 

Oh you're right, only a little more than half the U.S. population drives 30 or fewer miles a day. For everybody else, it would only help for a good fraction of their drive.

Actually, I'd prefer a smaller range for a cheaper price. Get a 15-mile plug-in for 1/2 the price? That and an EBH, my gas engine wouldn't kick in except sometimes on weekends.

 

EV Battery range is also gonna vary depending on driving technique. If one is really adept at gliding, and can pull off good numbers in a std Prius, I can't imagine what could be accomplished with a Hymotion type mod.
All the pulses would be off battery power, and still maximize the glides.
If the "30 mile" estimate is based on continuous battery depletion, seems one could get some 90 miles? out of the pack with some good P&G technique.
And what kind of MPG would that translate into?

 

orenf, I'm not sure about your logic for purchasing the HyMotion pack.

Just like how you argue that you bought a Prius because it's environmentally friendly (because it burns less fuel), the Hymotion upgrade also has other similar benefits besides saving money on fuel. Such as reducing consumption of a scarce resource, reducing reliance on foreign oil imports, reducing greenhouse gas emissions, etc.

If we could put a monetary value on those benefits, then we'd know the true cost of gasoline and the true benefit that the HyMotion upgrade would provide.

What you've also neglected to mention is that the LiIon battery in the HyMotion pack is significantly more environmentally friendly than the stock NiMH battery in the Prius.

Even if Hymotion doesn't want the dead pack back, doesn't everyone have a hazardous waste program? You simply drop the pack off there and they will recycle it / dispose of it as necessary.