REVIEW: Hymotion Battery Plug-In Prius

[jrmgkia]

Originally Posted by TheForce

I just got my Hymotion welcome package today. Here is what it includes.

Inside the envelope there is an updated instruction manual, a quick start guide that looks like it can hang on your rear view mirror, a square 100+MPG sticker that looks like it will fit on the gas door, a Hymotion window sticker, an oval PHEV sticker and a Hymotion logo "H" keyring.

I have scanned in and uploaded the new manual. This is reversion 03.
http://jaygroh.dreamhost.com/priusch...uide%20V03.pdf

The Force, I read over the new version of the L5 owners manual that you posted and discovered something that I didn't know before. The regen braking of the Prius never charges the L5 battery pack. I am guessing that while using the L5 the stock Prius battery gets "regened" until it is fully charged and then the extra regen is wasted, am I correct? I also noted in the manual that you are strongly warned not to turn off the L5 battery back while driving. My thoughts were this:
1. What would happen if you did turn off the L5 battery while driving, would it really cause any problems?
2. Could you drive with the L5 on and use the regen to fully charge the stock Prius battery. Then switch off the L5 battery and drive in regular EV mode until the stock battery is down to only 2 charge bars. Then switch the L5 back on and regen the stock battery again? Assuming you could do this 5 times before the L5 is discharged it could gain you 5-10 extra miles of EV only driving.

O.K. Force so now tell me why I'm an idiot and how this won't work. The only reason I can see is if the regen does not go to the stock battery when the L5 is engaged, but rather is just wasted as heat. If that is the case then I would love to see the first hack to make it so the L5 accepts the regen charge from the Prius.

[PeakOilGarage]

Originally Posted by jrmgkia

The regen braking of the Prius never charges the L5 battery pack. I am guessing that while using the L5 the stock Prius battery gets "regened" until it is fully charged and then the extra regen is wasted, am I correct?

That is sort of correct. The regen energy only goes into the NiMH stock battery. In the background, you can see that the stock battery spends most of the time at 7/8 or 8/8 of capacity. It is almost always green. But that energy is being used also at the same time as the Hymotion battery.

I do see it going down to 6/8 sometimes, but it easily goes back up to 7/8 or 8/8 while just driving around town in pure EV mode.

It is as if the Hymotion system just floods the Toyota system will all of the electricity that it could ever want.

Based on where the Hymotion battery is connect, it is directly at the same point between the stock NiMH battery and where those cable lead to the Toyota drive system.

So the Hymotion is not "behind" the NiMH battery. It is accurate to describe them as side by side together feeding the Toyota drive system.
And the NiMH is not being asked nearly as much to contribute, so it is typically at 7/8 or 8/8 most of the time.

Some of the other Hymotion owners might be able to add more to my observation.

Originally Posted by jrmgkia

I also noted in the manual that you are strongly warned not to turn off the L5 battery back while driving. My thoughts were this:
1. What would happen if you did turn off the L5 battery while driving, would it really cause any problems?

I have done it many times to save the Hymotion battery for in city driving, especially if I know I am driving more than 30 miles. I would rather conserve the Hymotion battery for speeds under 40 mph. The only time I use the Hymotion battery on the highway is if I know that I have enough remaining charge to get home or to work (where I can also recharge).

There are no negative effects to turning off the Hymotion system while driving. It might cause your cruise control to lose it's settings. No big deal. The Hymotion system turns off automatically while your are driving if you run out of energy, so clearly there is no harm to the vehicle from turning it off with the switch.

Originally Posted by jrmgkia

2. Could you drive with the L5 on and use the regen to fully charge the stock Prius battery. Then switch off the L5 battery and drive in regular EV mode until the stock battery is down to only 2 charge bars. Then switch the L5 back on and regen the stock battery again? Assuming you could do this 5 times before the L5 is discharged it could gain you 5-10 extra miles of EV only driving.

I have done that a little. If I notice that the stock battery is at 8/8, I have switched off the Hymotion battery and driven a little bit until it is 6/8, then I switch the Hymotion battery back on.

I think the gasoline engine would come on automatically a long time before getting to 2/8. But also, it would be difficult to maintain EV mode that long with only the stock battery.

When the Hymotion battery is on, it give you A LOT more play in the gas pedal to stay in EV mode. Very easy to maintain EV mode. Also, the Hymotion battery will go all the way down to 0/8 and keep providing 100% until the bitter end.

With the stock battery, it turns on the gas engine to recharge a long time before it gets too low.

[PeakOilGarage]

I did a Hymotion pure EV range test tonight.
Here is what I did. Full Hymotion battery to start.

I drove around with the Hymotion battery off in order to warm up the Prius. Then I made sure I had a relatively flat course and traffic was at a minimum. The traffic was light, but for the first 10 miles, I hit a lot of red lights. I tried to maintain a speed of about 33 to 35 mph. Also, it was raining and there were a lot of puddles on the ground. I am not sure if that causes a measurable difference in terms of resistance on the road.

Under these conditions, I got 20 miles out of the Hymotion system in pure EV mode.

I think that if I had not been dealing with so many red lights I would have gotten 22 to 25 miles in pure EV mode.

Also, I have heard that the battery range gets better after a few discharge cycles. We will see. I will try again tomorrow night on a route without the red lights.

After that, I will be testing my highway electric assist range at 60 mph with cruise control on.

[Flying White Dutchman]

"After that, I will be testing my highway electric assist range at 60 mph with cruise control on."

want to see that!

[Flying White Dutchman]

.double

[TheForce]

Well since I said I would fill up on October 12th I figure I better tell you my results. I actually filled up on the 11th because my preferred gas station is closed on Sundays.

Anyway here are the numbers.

1275 Miles
7.862 Gallons of gas @3.199/gal
210.403kWh @ 8 cents per kWh
162.2MPG

Cost is 3.3 cents per mile on this tank.

According to my CAN-View I could have gone another 400-500 miles before I needed to fill up.

I'm finishing up the review and should have the final draft ready in the next week or two. I'm sure you all have a lot of questions and I'm sure my final review will answer most of them. If you have any questions just post them here and I will try to answer them.

[ualdriver]

Originally Posted by TheForce

Well since I said I would fill up on October 12th I figure I better tell you my results. I actually filled up on the 11th because my preferred gas station is closed on Sundays.

Anyway here are the numbers.

1275 Miles
7.862 Gallons of gas @3.199/gal
210.403kWh @ 8 cents per kWh
162.2MPG

Cost is 3.3 cents per mile on this tank.

According to my CAN-View I could have gone another 400-500 miles before I needed to fill up.

I'm finishing up the review and should have the final draft ready in the next week or two. I'm sure you all have a lot of questions and I'm sure my final review will answer most of them. If you have any questions just post them here and I will try to answer them.

Very interesting. Thanks for such a detailed analysis.

[ibcs]

Great job Jay,

Thank you for keeping everyone informed. I'm anxious to see your final write up, but the mileage alone is very impressive.

---Kent

[boxer93]

Jay,
On your review will you show inverter temp? I've been reading up on Grill Blocking and I didn't know if you saw a difference between pre and post Hymotion install.
Thanks
Chris

[ibcs]

What is the inverter temp symbol on the scangauge? This would be very interesting to watch when doing a lot of EV.

---Kent