3KW EV Conversion - Plug In Supply

very nice, keep the faith!

 

I see this as a huge "killer" problem. The big reason why this whole idea can't work even with a large battery and perfect fooloing of the sensors is the simple fact that the electric traction motor is not big enough. Feed it all the battery ppower you want and you are not going to go even 35 miles per hour up a steep hill. You will annoy anyone who is following you and worst of all you might over heat the electric motors, although they are well cooled.

A "real" EV needs a very large motor. The Prius C motor really can't power the Prius C alone except on flat level ground at low speed. You never get onto a freeway.

 

The traction motor in the C is 45kw, that's plenty of power to get the car to 60mph and keep it there. However the battery can only output ~17kw (and the output of the boost converter will also be at this level), which as you say is not powerful enough for highway driving or snappy acceleration in this vehicle.

 

The Prius in general (Plug In excepted) is not a good candidate for "PHEV" conversion unless you use the "Enginer" type of conversion. Here's why:

1) It is designed as a gasoline (primary) car with electric assist. It is for this reason that the electric motors do not have enough power to safely propel the car. With electric mode only, the car is really underpowered and not safe to drive on the streets
2) The Prius has advanced, high-tech monitoring systems (called ECU's) that all work together to make this engineering marvel work. Adding more battery capacity requires modifying what one ECU sees which causes multiple problems with other ECU's.

The old adage that "every time you fix a problem you have to solve another" has major application here. A typical scenario may go like this:

Problem/Fix: The battery runs out or low in "EV" mode, I need a bigger battery (thousands of dollars)
New problem: Adding a bigger battery requires spoofing or/reprogramming the Battery ECU
Fix: Then I will reprogram/spoof the ECU so I can use the bigger battery (hundreds of dollars)
New problem: Now that I have this bigger battery and the ECU spoofed, the ICE still wants to come on when I accelerate too much
Fix: I can use OutOfGas mode to stop the ICE from coming on (cheap)
New problem: The stock electric motors/inverter setup are not strong enough to power the car in most situations
Fix: I need to install a larger electric motor (thousands of dollars)
New problem: The inverter cannot power the new motor
Fix: I need a new motor controller/inverter (thousands of dollars)
New problem: I've spent so much money on converting my Prius that there is no return on investment and I can't sell it b/c noone wants a car that's had this many mods
Fix: I need to take every mod off and return the car to its original state (thousands of dollars)

(It reminds me of a story I heard in grade school where a king had mice in his castle and wanted to get rid of them. So... he brought in cats then he had too many cats so... he brought in dogs this continued until he brought in elephants. Having too many elephants, the only thing he could think of to get rid of the elephants was mice. He brought in mice, the elephants left and he lived happily ever after)

There are other numerous reasons why the Prius shouldn't be converted unless you're going to gut the HSD and add an electric drive system that can handle the requirements. The stock Prius electrical system cannot handle the requirements on its own. It needs the gas engine and the gas engine needs the electrical system. They have a symbiotic relationship.

 

Is that plenty of power to get it to 60mph on an upgrade? I'm betting 35 mph in a C (going up a hill) would be tough to achieve.

 

Yep. My first car had 37kw of power and I got that baby up to 103mph.

 

No, I'm talking about the 17 kw that's available to the C's motors.

 

Right, and I said 45kw is good, 17kw is bad.

I guess I was just being pedantic that the -motor- is actually powerful enough, just the electrical supply is not.

 

the equipment looks to be very high quality?

 

I'd need to hear from an expert on charging. Let's get a Boeing 787 Battery Engineer to chime in here. Specifically, what happens when you overcharge?

 

don't modern chargers prevent that from happening?

 

Just thought I would make all of you aware of a post I read in the Gen II Forum regarding PIS. Here it is.

"BTW, Robb from PIS won't support us and our customers either. Not only did he take money from us for his 4kwh product and never send us product or a refund, he refused to honor his warranty or provide software updates on other systems we purchased. He then started bashing us on his website and saying things about our company and offerings that are untrue.​

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Bottom line, buyer beware when dealing with PIS.... "​

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Read more: http://priuschat.com/threads/plug-in-supply-diy.105157/page-16#ixzz2IjqaxKUk​

I don't know this guy but he doesn't seem too happy with PIS

 

Geeze, and I thought I had a good on-topic joke.
An expert Boeing 787 Battery engineer.....
Overcharging....
Get it?
I'm in Seattle where those are made, so all that noise about the battery fires in the new 787 Dreamliners is all over the news here. Guess not so much in other places.

 

sorry, i'm a little slow on the uptake!

 

So I read this entire thread, and I agree it's mightily interesting. I doubt i'd ever do this myself, though, but it's fun to follow nonetheless.

I totally understand usnavysgtc's points, and in fact, would think this endeavor futile if not for the fact that MJfrog has reportedly already made this mod and has been using it successfully since August, getting ~200 MPG (calculated using gas only). According to his posts in this thread, it sounds like his Prius has the ability to engage the ICE whenever it needs extra power, like on freeway jaunts. And that seems to be the key here: Can you get the Prius system/software to ALLOW for EV-only usage for slow-mid speeds (say up to 45mph), then have the ICE automatically kick on for higher speeds.

It seems to me the whole point of this extra battery pack is just to prevent having to use the ICE to charge it, but rather use electricity from the grid instead, which is considerably cheaper than gasoline.

I agree wholeheartedly that this solution should NOT involve cutting off the ICE entirely, as it should still be accessible in those moments where more torque is needed. Who cares if you're still burning gas if you're only using 8 gallons of it every 3 months? That's hardly anything, and completely worth the added safety of .

Ultimately, I guess the best person to settle this issue would be MJfrog himself, as he's actually been using this system for the past 6 months. Is his mod EV-only, like what Jeremy is planning (by removing fuse)? If so, what are his driving habits? Does he have enough acceleration? Is he a danger to other drivers? Has he been in situations where he needed more power but didn't have it?

 

Ok, let me give you current status and try to answer a few of your questions.

As of the end of December, I removed the battery packs from the car. This was done because I don't have a heated garage to park in overnight and Michigan temps have been VERY cold since late November. I was using a space heater to attempt to keep the batteries near or above 32F, but finally gave up and removed them. When overnight temps are 32F or above (probably sometime in March) I will put them back in the car.

My daily commute is ~17 miles each way...I can charge at work. When the weather is warm enough, I do this commute in OOG mode (i.e. temporarily pull the fuel-pump fuse/reinsert it/clear codes). This mode allows for all-EV mode for as long as the battery holds out...usually for my entire commute. To reset OOG mode, it is necessary to pull over, shut the car off, and restart it. As long as I can get recharged before I need to run errands and I don't have to do many highway trips, I can average >200 mpg per tank (not including electric costs in calculations).

My inbound commute begins at ~5:20 am--traffic is minimal and I do not feel I am a danger to other drivers. I have one stretch of road that is 45 mph for ~3 miles that I typically drive @40 mph. Otherwise I am driving about 35 mph for the majority of the commute. My home commute begins at ~3:20 pm...the reverse of the above. Traffic is moderate at that time and except for 'slower than average' acceleration from lights I am traveling with the flow of traffic. Lights are timed fairly well, so my stops at stoplights are minimal. I have never (knock on wood) been in a situation where I needed more acceleration that the car was capable of providing. If I had it to do again and had the $$$, I would have purchased the 10 kwh system instead of the 4 kwh version.

The times where I haven't been able to recharge (enough) or will be doing highway driving, I do not use OOG mode.

[edit]

FWIW, even on my >200 mpg tanks, I only went two months max on a tank of gas. If you don't have driving circumstances similar to mine, you will NOT be getting results as good as I do.
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[edit2]Just as a further clarification; this kit is a PHEV conversion! It does NOT make the car into the equivalent of a Volt, Leaf, or PiP. Expecting it to perform like those vehicles is WAY beyond its capabilities.[/edit2]

hope this helps

 

This PIS conversion does not allow for it. With this conversion, you have to remove the fuse or install a switch to cut of fuel, (OOG mode). Once in OOG, if the ICE is needed, you have to pull over, turn the car off and then back on. This will put the car in normal hybrid mode.

Yes it is. Great idea, hard to implement. Every solution causes another problem as detailed by my earlier post. The problem is that the Prius software/hardware interaction has been written with the symbiotic relationship of the ICE to the MG's and vice versa. Cutting the ICE out of the equation requires the extreme measure (extreme is my word, yours may be different) of cutting off fuel to it. To do this right, the software needs to be rewritten (no easy task). I'm betting that this software rewrite would encounter the same "every solution creates another problem" scenario. If we just take a quick look at it, how would you accomplish telling the ICE to "stay off" when there's no traffic or dangers requiring acceleration but, have it come on when there is?

All these questions are great but, do they answer the real question? If he has certain driving habits, has enough acceleration, is not a danger to others and hasn't been in a situation where more power is needed, is that a guarantee for all those variables in the future? Let's face it, the Prius is underpowered with the ICE.