Engineer PHEV kit

You don't make your money back on PHEV kits unless you drive them to the ground. You do it for cool and/or geek points as well as limiting gasoline use. Limiting because of environmental/political reasons, not financial.

So if you are asking if it is worth it as in, "will it save me money", then no. Otherwise yes.

 

I like it - doing it for geek points.

 

The prius is able to extract about 12.5kwh of power from a gallon (US) of petrol. if you have the 2kwh Enginer kit (1.6kwh usable, and about 1.4kwh going to the drivetrain) you save .11 gallons of petrol. subtract that .11 from whatever amount you normally use in a day, and divide your miles driven by the reduced number.

So say you do 40 miles at 50mpg. on a normal day you use 0.8 gallons of petrol. take out the .11 and 40 miles divided by 0.69 is 66.9mpg.

The 4kwh kit (3.2kwh usable, 2.88kwh to drivetrain) displaces 0.23 gallons. so 40 miles divided by .57 gallons is 70.2MPG.

That method should work fairly well, post up your current mpg and distance and we'll take a look!

 

oh ok. well what's your usual mpg and miles, then we can see what you'll save.

 

The performance also depends on your usage. If your driving is mostly city & around town; the MPG is really good, especially if you keep below 34mph and use the EV mode as much as possible. High speed & hill climb performance are not that great. I think there are two Prii on this forum with 8kwhr + 2 converter and they are able to overcome the highway limitation, getting upward of 90-110mpg.

The saving factor also depends on your source of electrical power. The best of course is "free" from solar panels. Actually, the return on solar panel investment is 3x faster if you use the generated electricity to drive rather just powering your house. My back of envelop return calculation: most utilities charge $0.10/kwh, so you'll save $1 per 10kwh generated. A Prius consumes (conservatively) 200wh/mile --> 1kw/5mile --> 10kwh/50miles ---> translate to $3 at $3/gal and 50 mpg. So comparing $1 versus $3 gives the 3x.

My reasons were: 1: stop support the bad oil people (foreign & domestic) 2: save some blood shed from our soldiers 3: CO2 & pollution reduction 4: save some $$ (I have solar panels) 5: the fun factor.

It's no brainer if you believe the true-cost of 1 gallon of gas, around $7/gal if you include the military & "defense" cost and around $11/gal if you include the all the health/medical factors. Take the gov't standard mileage rate presently at $0.50 per mile. This figure is what the IRS & power of being think to compensate for using your own car. Assuming 50mpg and a Prius, that's $25/gal. Assuming half for maintenance, though with there is less maintenance cost driving with electricity, leaves you $12.50/gal.

sorry, i digress...just my 2 cents

PS: the Enginer kit is on sale: $1700 & $2500 for 2/4kwh system; I may have to upgrade ! don't forget you'll get 10% federal tax credit ! some state also have credit, unfortunately not in California

 

I am pretty sure you pay $1k more for the Enginer kit in California for something... I hear about it all the time, not sure what it is. Could be internet hearsay.

Also to those using 2 of those DC-DC converters, I am truly shocked and horrified. I do not know why he (Jack?) does that. They won't be putting out the same voltage. It may be close, but it won't be the same. Then they fight over which one powers what and loop back through eachother since they aren't balanced. Basically wasting a bunch of power in heat as they continually try to balance a 240vdc output. You really need a smarter system for that kind of power output, even the smallest unbalance becomes a huge heat factor because of the current involved.

 

OK, some 'real-world' figures (exclusive to me of course...YMMV).

I bought an '04 Prius in April 2009. My mileage for the summer months calc'd out to 52-56 mpg with one tank at 59 mpg and another at 61 mpg (probably short tanks).

I had the 2kwh Enginer kit installed end of August and got consistently 59-64 mpg per tank through the end of November when temps dropped below daytime highs of 45F. After that, tanks ranged in the upper 40sF through early March when the temps began to warm up again. I use a grill block, but not an EBH.

My daily commute is ~19 miles each way with NO opportunity to recharge. If I could, I would probably be doing another 3-5 mpg better.

Morning commute averages about 35 mph while return trip via another route averages about 45 with a 9 mile stretch of 55-60 mph. I do extensive P&G on the trip in, but am limited in opportunity on the return trip.

Since I bought my Prius I have 'saved' an estimated $746 in gas vs the 30mpg average of my previous vehicle.

My guestimate (for me) is the 2kwh Enginer kit boosts my mileage by 6-8 mpg.

 

Of course it is. You are really stressing the traction battery this way. No way will Toyota pay for a new one if it dies.

 

Actually using 2 converters should work just fine. When the battery is up to 240 volts, then it doesn't matter if one inverter is charging slightly higher then the other. Once the battery is under load, the voltage will drop enough to have the voltage below 240, and both inverters will be current limited, so you will get output from both of them at the same time. That will provide more acceleration capability before the ICE cuts in.

 

No, you will not stress the Prius battery pack having a secondary "system" connected to it providing a controlled power.
Under the Toy. dealers eyes you will be voiding their warranties only by the existence of any accessory connected to "your" vehicle. That is how it works, I learned that by the experience of it.

 

I didn't pay the extra $1K in CA because I did my own install, thus it was purchased as a DIY "kit". I believe you do have to pay the extra to have it install "officially".

I have cellLog monitoring the Enginer batteries, and the DC/DC behaves like a constant voltage source, putting out juice depending on the load (OEM pack) voltage. For example, when the Prius is in regen mode, there is hardly any drawn on the Enginer pack as the Enginer converter is seeing a higher external voltage.

I am thinking of adding a second Enginer converter and set to higher voltage, may be 260v, to force charge for hill climbing & freeway speed. By keeping the two switches, I can use the 2nd converter as needed, as a "boost".

But you are right about the efficiency, as the converter gets quite hot, converting couloumb to heat. I wonder how real is the listed efficiency ? 80+% ?

 

i thought you already ordered it? canceled?

 

what type of driving do u do ? mostly freeway ? hills ? around town ? I think the system excels on flat land, and around town. And if you have access to frequent opportune charging, i think you approach 100mpg with a 4kwh system. The 2kwh is just too small; but you can get the 2kwh now and add another 2kwh later ($900).

Is there tax incentive in NY ? you can claim the 10% federal tax credit. My back of envelope estimate: with $3/gal in CA, for a 50mpg assumption, that's $0.06/mile. The Prius is estimated to take 200wh/mile, so at $0.10/kwh typically, that's $0.02/mile. I have solar panel so my charge is mostly $0/mile.

I did make myself wait until our car has 150kmiles to start making mod; since it is now out of warranty. It has been a long wait. BTWay, it's still amazed me when I think of the $ saved with the Prius. My wife wanted a minivan back in 2004: assuming 25mpg (on a good day), (150000miles/25mpg) * $3/g ~ $18000 in gasoline. With the Prius at 50mpg, we spent half, saved $9000; some chum change. If only the gas price goes up ....