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-   -   70 MPH in a Prius in EV MODE! (

bennelson 06-09-2009 11:31 PM

70 MPH in a Prius in EV MODE!
I have been pestering a couple of guys in Chicago lately about plug in conversions.

Unfortunately, most Prius converted to PHEV suffer from only being able to go low speeds on electric only.

These guys were able to get one up to almost 70 Miles per Hour using only the electric motor!

Peep the video!

bgd73 06-09-2009 11:36 PM

I took an interest in the bke recently featured on jay leno, this is even more interesting. I hope this becomes real and cheap, realistically cheap. the city chores, it would be nice.

Daox 06-10-2009 07:16 AM

Hmmm, very interesting. I'll definitly be looking up their web page today.

bennelson 06-12-2009 05:19 PM


This time it's actually watchable!!!!!

Daox 06-12-2009 06:54 PM

Again, veeeery interesting!

Matt Herring 06-12-2009 07:24 PM

This is interesting but given the design of the MG1 and MG2 in the Prius engine it leaves alot to be discussed before deeming it "safe" for the looks like fun but it may not be in the long run. When I first started getting into the Prius engineering (shortly after I bought it) I immediately was told "no neutral coast near or over 60 mph (and most people told me to avoid it all together). I still use it but no where near 60 mph.

The software that Ewert has created (and the upgraded battery pack they install with it) is still operating with the original Prius engine. Because of this the "gears" that simultaneously operate in the car ICE are still in play. The MG1 in that engine is built to sustain up to about 10,000 rpm (in the 62 mph range). In essence, the MG1 continues to spin when in EV mode to protect the engine and at 70+ mph it is clearly reaching it's limits before "overspinning" and doing harm to the engine (a poster on here showed me the math in my Prius thread if you want to reference it). This is something I am very aware of when doing any neutral coasting in my Prius (I don't do it anywhere near 60+ mph).

The software Ewart has created is basically a "hack" for the Prius engine tricks the engine into thinking the SOC is high enough to use EV mode (thus allowing it to stay in EV at that high of speed...usually only available below 42 mph) and keeps it EV mode beyond the 41 mph limit. This is a problem in my mind because while EV mode is built into the car it is not built into the car at 42+ mph...really only up to 60ish mph where the MG1 is nearing "overspin."

Another area to consider is inverter temps at this high of speed and length of time while pulling higher amps to stay in EV mode using their system. Not only are you overflexing the Prius capabilities in terms of the inverter you are also spinning the MG1 at a ridiculously high rate. I'm no expert on the MG1 and MG2 in the Prius but I know that the MG1 spinning in neutral or EV mode over 60 mph is a no-no.

I'd like to see more in regards to what rpm's the MG1 is at while they are at the 65-70 mph speeds.

Daox 06-12-2009 08:11 PM

All very valid points Matt. I hope they address them. Time will tell.

Matt Herring 06-12-2009 08:32 PM

Ewert has clearly developed an interesting product...and I'd be surprised if they engineered it to "fail" within the Prius engine system. They obviously intend to mass market the software/technology so it must have some sort of override that safely operates the vehicle.

But, I'd just be interested to read how it effects the Prius engine and what safety precautions it takes in regards to the engine and inverter. The fact that they install a larger battery to run the system says alot up front...they recognized the amount of amps to run that high of a speed required much more energy from the battery (like more than 3x more than the stock Prius battery). That being said, the inverter temps have to be addressed somewhere along the way.

If anyone has more info I'd love to see it...cost looks to be around $2k...not bad to get extended periods of highway driving gas free.

bennelson 06-12-2009 10:12 PM

Of course that 2 grand is on TOP of the conversion cost to swap out to the BIG Nickel pack....

Matt, half of what you said is over my head. I am not much of a Prius guy... but I AM learning.

I just joined the PHEV discussion list and all the things you just mentioned are flying all over the place there.

A couple things I thought were pretty cool about this system is that it is possible to control the CAT warm-up. The USER could have control over when to turn the engine on and off. That REALLY opens up some possibilities in good fuel economy.

Also, even if you aren't driving 65 or 70 on this system, you can still go a bit faster than you could in a stock Prius while keeping the engine off, and you don't have to "reboot" the system to leave EV mode like you do with the Plug-In Supply system.

Another thought - On these conversions where the original Prius pack is completely replaced with a bigger pack, what happens to the old battery pack? How many needed to push a Geo Metro around? :thumbup:

Daox 06-13-2009 08:24 AM

Haha, the original battery packs are not big at all. The 1st gen Prius had a pack capacity of around 1.3 kWh, and I'm pretty sure they've been getting smaller ever since.

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