Hymotion and 52 MPH EV Mode -

[aminorjourney]

Originally Posted by Mike Dimmick

If it comes to that, I'm not sure it's a good idea to run the car for long distances without the transaxle oil pump running. This oil pump is driven by the engine - the oil pump shaft runs through the centre of MG2 and slots into the far side of the planetary gear set.

I haven't (since I have not undertaken any PHEV mods) been able to run the car more than a mile or so at 29mph*, so I don't know if the car would start the engine to stir the transaxle oil if you drove for a long distance in regular EV mode. It may not do, as the car was never designed as a PHEV. It is of course possible to run pure-electric up to 42mph; again, the battery won't last long enough to see if the engine would be started only to run the transaxle oil pump.

* for some reason, factory EV is limited to 29mph in the UK. This may be due to the default speed limit of 30mph in built-up areas if no other speed limit is indicated.

Interestingly, Mike, I can get 31 mph before my EV mode cancels!

But...

I think perhaps the thing we should all be thinking about is how the Toyota PHEV prius works. Reports are that it's simply a modified BMS/ECU program and a second OEM pack, similar to my own DIY mod. Given that and some thought, perhaps the high speed mode is okay - but only if you can cancel it without a reboot!


Nikki.

[jessebismarcknd]

I am assuming that using 52 MPH in pure EV mode would deplete the battery much quicker than going the same speed using the Hymotion pack without the 52 MPH EV mode. Right now I get about 30 miles using the Hymotion pack as normal. I'm only getting maybe 50 MPG (in 10 degree weather). If I could go 15 miles in pure EV and then average 40 MPG in standard Prius mode for the last 15, this would equate to 80 MPG overall....not bad if this would actually be the case.

[zcat3]

Thought I would post a quick update about using the Hymotion with the 52 MPH EV mode. Here are my observations so far:

1. It appears the pure EV mode allows for much more efficient battery use than the Hybrid mode. For example, my commute to work is 28 miles of almost all highway / freeway driving with 2 significant hill climbs - one of about 700 feet in 1.5 miles. With the Hymotion system I usually get to work with the 2 purple bars showing, and sometimes the Hymotion is drained before I make it all the way in. On a day like today, rainy and in the low 50s, my mileage coming in would normally be 70 -75 and the battery would almost be entirely drained. With the EV mode option, I can switch to pure EV for the last 2 miles or so and today I made it to work at 80 MPG with 3 bars showing (and the 4th bar had just dropped off in the last mile). Yesterday in similar weather I made it to work at 75 MPG and finished the day at 85 MPG (meaning my return home was 95 MPG). I did use the EV only mode for the last 3-4 miles of my commute. Previously I would only get 90 plus MPG legs on warm sunny days.

2. Do not mount the EV button next to the Hymotion button - I have now accidentally hit the EV button twice on the freeway. The last time I was lucky as trasffic was slowing down and for the last 4 miles on the freeway I never got over 50 - otherwise I would have had to pull over to reset the car to normal Hybrid mode.

3. For an NEV this system works great. I can drive all over Half Moon Bay (max speed limit 45) without using a drop of gas. I have solar on my house, so I actually produce the power for the car - pretty cool.

4. EV accelration is o.k. - not great. If turning from a stop onto a 45 MPH road, give yourself a much larger gap to get into traffic.

Not sure why Toyota has not moved faster on this - perhaps they think an added 10K to the price of a Prius would not be viable - and maybe for mass production they are right.

[baboonia]

3ProngPower of Berkeley installs the kill buttons in the drivers side "triangle window area." Driver (and passengers!) cannot hit the kill button accidentally.

Prius Dash Button Location

[zcat3]

Originally Posted by baboonia

3ProngPower of Berkeley installs the kill buttons in the drivers side "triangle window area." Driver (and passengers!) cannot hit the kill button accidentally.

Prius Dash Button Location

Yep - that works. As they installed mine in a factory switch location, I am sure they could just put a switch blank back in that area and move the button if need be.


One other thing I have noticed is that if you have EV enabled and turn the Hymotion switch off and then back on while driving (as you may want to do in a down slope area where you can get enough regen to propel the car without using the Hymotion pack) the car seems to continue to drain down the Prius hybrid battery for a bit after you switch back to Hymotion power. The downside of this is that if you inadvertently let the Prius battery get to purple (even when the Hymotion battery has plenty of blue) the Prius starts to go into battery protect mode and cuts way back on your power. I have had this happen twice where I could not longer maintain a speed of 50 on a 50 MPH road. The upside to playing around with this is you can maximize range. I got 85 MPG on my 28 mile commute home yesterday in cold rainy weather and only needed 3.6 kWh to recharge the Hymotion battery.

[ibcs]

Originally Posted by zcat3

Yep - that works. As they installed mine in a factory switch location, I am sure they could just put a switch blank back in that area and move the button if need be.


One other thing I have noticed is that if you have EV enabled and turn the Hymotion switch off and then back on while driving (as you may want to do in a down slope area where you can get enough regen to propel the car without using the Hymotion pack) the car seems to continue to drain down the Prius hybrid battery for a bit after you switch back to Hymotion power. The downside of this is that if you inadvertently let the Prius battery get to purple (even when the Hymotion battery has plenty of blue) the Prius starts to go into battery protect mode and cuts way back on your power. I have had this happen twice where I could not longer maintain a speed of 50 on a 50 MPH road. The upside to playing around with this is you can maximize range. I got 85 MPG on my 28 mile commute home yesterday in cold rainy weather and only needed 3.6 kWh to recharge the Hymotion battery.

I've had mine go into the battery protect mode a couple times. I thought the Hymotion was causing it due to excessive current. How did you resolve it with this situation ? I stopped and restarted back to normal, let the car charge the battery and did Hymotion on the return trip.

---Kent

[zcat3]

Originally Posted by ibcs

I've had mine go into the battery protect mode a couple times. I thought the Hymotion was causing it due to excessive current. How did you resolve it with this situation ? I stopped and restarted back to normal, let the car charge the battery and did Hymotion on the return trip.

---Kent

In my case I was lucky in that the people behind me were patient as I slowed to 42 and then got off the road. I got up some speed on a side road, turned the Hymotion off and was able to regen back up to 3 bars. This seemed to let the Hymotion system charge the Prius battery again. I am guessing that it you drop into purple on the Prius battery, which is technically a state the Hymotion system would not normally see while it is operating, then the Prius somehow stops the Hymotion from feeding current into the hybrid battery. By the time I got home the Prius battery was showing purple again, so the next day when I started the car I left the Hymotion system off and let the Prius reg the battery itself at which point I then activated the Hymotion system.

What's interesting is that if there were an integrated system that allowed regen, ev mode, hybrid mode all to work in concert, I would bet you could get a lot more mileage and MPG out of a 5 kWh battery system.

[Fibb222]

Sigh, you guys are so lucky..... well that's not fair as I could have worked harder in university.... I'm just so jealous.

[ibcs]

Thank you so much for pointing out the real problem. Today I started out in pure EV mode and drained the Prius battery. From your post, I was able to verify by showing the SOC charge on the Scanguage which always shows the Prius Battery. I was down to 38%. Fortunately, I was at my destination waiting to pick up my son. During that time the SOC climbed to the low 50's and I was able to EV all the way home.

Now my conclusion is that we are drawing more current than we can put into the regular pack when doing a high current EV. I was doing about 45 MPH, so I was discharging the main battery faster than the Hymotion could charge it back up. I feathered the gas a little, but the real trick was sitting and letting the Hymotion charge the Prius battery.

I must say, I love this stuff.

Thanks for your insight,
---Kent

[zcat3]

Kent - you may be right that on longer trips over 40 MPG or so that the Hymotion cannot charge the Prius battery fast enough so you see a slow drop in the SOC of the main Hybrid battery. This certainly coincides with the 2 times it has happened to me - both after maybe 5-6 miles of driving over 45 MPH.