Daox's 2004 Toyota Prius Build Thread

[NeilBlanchard]

Hi,

So, when you're stuck in traffic, you can force it to stay in EV mode? When the ICE comes on to charge the traction battery, does it run at a constant RPM?

[Daox]

When I'm stuck in traffic I could force it to stay in EV mode with the switch. I would have to come to a stop because you can only enable EV mode when stopped. Also, when you are in traffic your engine is likely already warmed up, and with a light foot you can keep it in ev mode without the switch fairly easily. The switch is more useful when you're doing a cold start and don't want the ICE on. Thinking ahead, if I added additional capacity to the pack via another pack in parallel (or make them switched), I could run much farther on EV mode and plug into a charger to make a PHEV.

When the engine kicks back in it does not stay at a constant rpm. Once it is on, it is the main form of propulsion in addition to powering the motor/generator to charge the pack back up.

I just programmed in some handy x-gauge features on the scangauge so I can monitor pack voltage and current draw/regen amps. This should prove very interesting on the trip to work tomorrow.

[Matt Herring]

Usually in heavy traffic you can stay in EV mode without the aid of an EV button. This can be done as long as the car is up to temp (above 160 degrees) and SOC is above 3 bars. If you are in heavy traffic crawling along as long as you don't cram the go pedal and lightly accelerate you can keep it in EV mode. I like to keep about a 2 car distance in heavy traffic so when I see taillights go out I can continue my crawl and be up to speed when the car in front of me begins to move or have enough time to slowly brake without stopping. This gets me moving but also gives me a head start on the car behind me so I don't hold up traffic and can accelerate at my own pace instead of the cars in front of me.

The EV switch is an advantage but not a huge one that will drastically alter FE. It's more of a safety net to preserve FE when the ICE would otherwise steal a little FE from you. EV switch is still a positive addition though.

When the ICE is forced to come on to charge the battery rmp usually runs in the 1200-1300 range. Using the go pedal with a low SOC you will commonly see rpm's rev alot. My normal throttle position when the battery is charged up keeps rpm in the 1700 range at 45 mph. With SOC low the same throttle position might run at 2000 rmp and rev to 2400 if I'm not careful.

[Daox]

I got the Prius up on ramps tonight to take a look at the underbody. There honestly doesn't look like there is a ton of work that can be done here. The bottom side is already very flat. The only area that could use covering up is directly under the engine bay and along the exhaust tunnel.

I didn't get a good look at the very rear end of the car yet, so I'll check that out later.

[bennelson]

Here's a video of the first test drive after installing the EV switch.

I was surprised at how briefly the car can drive on electric only.
It seems that the EV only switch would work best with a Plug-In Hybrid.

http://www.youtube.com/watch?v=hdfTkRf72FA

[Daox]

I can't see the video at work. However, I will comment that the pack wasn't fully charged when I parked the car so that hurt distance. The other thing was, and I noticed this after the fact, but the AC was on and that runs off the pack too. I was also trying to see how fast of acceleration you could get in EV mode.

Thanks for taking and posting up the video Ben.

[MetroMPG]

Interesting vid. Learning some things about the Prius 2 that I didn't know.

And I heartily second the call for a Prius EV mode vs. Electro Metro drag race!

[Matt Herring]

Interesting video...had never seen the EV switch in use before...had only read about it from people that had it installed.

I'm sure you're getting used to the new EV switch and finding what situations it works best in. From what I have read it's best applications are in stop and go traffic when you might have a hard time keeping it in EV at low speeds (and need more power) and situations when ICE would rob you of FE like warmup phases.

The EV switch is tricky to balance the allure of getting gas free travel vs. running the battery too low and forcing ICE to run to recharge the battery. I would guess it is best to use just before a downhill so the regen will charge the battery back for you and in stop and go when a feather foot is hard to maintain while staying in the flow of traffic.

Best of luck with the EV switch...it's cool...nice work bro!

[alohaspirit]

that was a pretty good video

a lot of my questions were answered

i am wondering how is this different from normal driving w/o the ev button

cant you keep it in EV mode with slow driving or will the engine just kick in at a much lower speed?

[Daox]

I actually do have one function for the EV switch so far. I have a relatively long driveway and I don't like to drive real fast on it (around 10 mph) since we recently put down new gravel. So, in the morning I use it to creep out of the driveway. Once I'm on the road and can get up to speed I kick it back into hybrid mode so the gas engine can warm up.

Thankfully, I don't hit too much stop and go. I'll let you know how it works if I do hit some though.