EV range and performance?

Scorpio · 08-22-2004, 07:47 AM

Looking at buying a new 2004 Prius but a couple of questions

In EV mode...

What speed can be maintained? Will it drive around town just on EV and not embarress itself?

How far can it travel on EV

Reason for the questions are that I have two sets of journeys - one is 25-30 miles on fast roads at 40-60mph and the other is a 5 mile trip into town where I never exceed 30mph.

Would be nice to consider that I could do the town work solely on Electric power and recharge the batteries on the faster runs.

Also, does anyone know if aftermarket battery charges are available? Perhaps running from a wind charger (we live on the coast!!)?

Thanks

Scorpio

**efusco** · 08-22-2004, 08:42 AM

EV range is quite short...from a full charge you might go 2.5 or with a tailwind, downhill and ideal conditions 3 miles.

Realize you'll have to install you own EV button as they're not standard or available options in the US.

I is possible to add additional batteries yourself to help extend the range, but that can incur other problems (no lubrication pump for the planetary gear system and such). There are no chargers available currently. There is on made, by Toyota, but it is very expensive ($5000 range I think), no one I've heard of has been able to aquire one yet, and it is very very slow. The problem there is that you have to syncronize charging with the ECU or the system thinks there's a problem. There are ongoing projects to dramatically extend the EV range of the Prius, but those efforts are early on.

Finally, top speed is 34mph in EV mode (with button, up to 41mph in "normal driving, but harder to achieve). Acceleration is quite slow compared to with the ICE.

Scorpio · 08-22-2004, 09:44 AM

Thanks for the info.

We are UK based so we get the EV button as standard. 3 miles is a heck of a short distance though

As I understand it, the battery pack is a stack of 130 or so D NiMh cells which are packed in a matrix of Serial/Parallel mode with temp sensors and a couple of cooling fans.

It is quite simple to obtain NiMH D cells from surplus outlets and we can generally pick them up here in the UK for around 50p ($1) apiece in bulk.

Therefore building a battery pack that will lie in the floor of the boot space and approx 4" deep, complete with temp sensors and switchable cooling fans is quite practical and certainly possible for a 2KWH unit to be built for around $700 or so.

Could such an item not be installed in parallel across the existing battery pack? Does the CPU use voltage sensing to determine charge state etc and would additional capacity therefore be compensated for (in the same way that it senses a dying battery pack).

I'm fully aware of all the safety precautions etc of working with NiMH and high voltages.

Thanks for your help so far

Scorpio

**efusco** · 08-22-2004, 10:47 AM

Yep, Scorpio, you're on track to how it's been done....I have additional information but I'm not sure how much I'm at liberty to share. Let me do a little research for you. Those who've added additional NiMH batteries that I'm aware of here have incurred costs more on the order of $1500-$2000USD.

Additionally, as I began to suggest, there's some concern that an additional oil pump is probably necessary for prolonged EV mode to lubricate that system.

Scorpio · 08-22-2004, 10:57 AM

Many thanks Evan

Any further info would be most helpful.

Bear in mind that I am after extra range and not speed - 35mph is more than adequate for our needs.

If the EU version includes an EV button then surely there must be sufficient lubrication already built in to the system. After all, Toyota doesn't say anything like 'Only use EV for 2 miles' or similar and they don't know that I don't live at the top of a mountain with a 10 mile downhill ride into town.

Just a thought.

We can buy those NiMH D cells very cheaply through military surplus routes - they come complete with solder tags etc. They just need testing before usage as 1 in 10 is generally faulty.

Thanks again

Scorpio

**efusco** · 08-22-2004, 11:45 AM

I think Toyota DOES believe that extended range EV could become a problem, they've even addressed it in this Patent Application The theories I'm familiar with suggest that some residual lubrication is almost always present, but with extended use could be depleted. It is not difficult to accomplish.

Scorpio · 08-22-2004, 11:53 AM

That's interesting.

However the EV button can be used when the vehicle has not been driven using the ICE - say after a lay-up of 2-3 weeks when any lubricating oil has drained or dispersed. So operation of the Electric drive would result in no additional lubrication of the ICE or the epicyclic gearbox. However my very limited experience of such gearboxes is that they are 'sealed for life' units and hold their lubrication internally.

The problems could arise if the ICE was spinning during EV use - although then I would imagine that the crankshaft driven oil pump would circulate lubrication oil throughout the ICE.

If I am not understanding the issue correctly please tell me. What other lubrication is needed other than ICE or gearbox?

Thanks

Scorpio

**efusco** · 08-22-2004, 12:14 PM

Hold tight Scorpio, I'll give you more data when I have 'permission'...hang in there.

Scorpio · 08-22-2004, 12:19 PM

Just re-read the application and I think that the vehicle actually handles the issues of lubrication by calculating the time since the ICE was last used and the various system temps and then using a map of the viscosity index of the oil (NOTE: ALWAYS use the recommended oils or else!!) to determine whether additional lubrication is needed. If it is then the Electric motor spins the ICE at idle speed so that the crankshaft oil pump circulates the oil for a predetermined time.

It's interesting that earlier in the application they refute the use of an Electric oil pump because it lowers the engergy efficiency - however they then advocate the use of the ICE being spun by the Electric motor to circulate the oil - that's really not efficent and will accelerate wear on the ICE - imagine the energy being wasted.

More likely is that as the ICE is a standard 'off the shelf' engine which already has a built in oil pump, then they decided to use the method of spinning the engine when lubrication is needed. But it's a bit unfair to claim in a Patent application that they chose not to use an electric oil pump because it would be inefficient.

The only real question is whether the software algorithm in the ECU calculates the oil lubrication requirements over an indefinite time period - my guess is that it probably does for my previously outlined scenario - top of mountain downhill to town.

Scorpio

PS Sorry our posts overlapped - I'm sitting tight

bri1600bv · 08-22-2004, 12:19 PM

The Prius battery is about 2kwh of energy, but usually doesn't get drawn down to below 50 or 60%, from what I've read.

1 kwh should take you about 4 miles if at low speeds without stopping and starting alot. That's my guess anyway.

I don't know if getting more batteries would be worth it. How would you get the software to recognize your new battery source and all? Otherwise it might start the engine as soon as the original pack gets down to 50% of charge.

08-22-2004, 07:47 AM	#1
Scorpio Join Date: Aug 2004 Location: Scotland Posts: 8 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	EV range and performance? Looking at buying a new 2004 Prius but a couple of questions In EV mode... What speed can be maintained? Will it drive around town just on EV and not embarress itself? How far can it travel on EV Reason for the questions are that I have two sets of journeys - one is 25-30 miles on fast roads at 40-60mph and the other is a 5 mile trip into town where I never exceed 30mph. Would be nice to consider that I could do the town work solely on Electric power and recharge the batteries on the faster runs. Also, does anyone know if aftermarket battery charges are available? Perhaps running from a wind charger (we live on the coast!!)? Thanks Scorpio

08-22-2004, 08:42 AM	#2
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 14,709 My Car: 2004 Prius Package: #9 Nominated 1 Time in 1 Post TOTM Awards: 0 Friends: 26	EV range is quite short...from a full charge you might go 2.5 or with a tailwind, downhill and ideal conditions 3 miles. Realize you'll have to install you own EV button as they're not standard or available options in the US. I is possible to add additional batteries yourself to help extend the range, but that can incur other problems (no lubrication pump for the planetary gear system and such). There are no chargers available currently. There is on made, by Toyota, but it is very expensive ($5000 range I think), no one I've heard of has been able to aquire one yet, and it is very very slow. The problem there is that you have to syncronize charging with the ECU or the system thinks there's a problem. There are ongoing projects to dramatically extend the EV range of the Prius, but those efforts are early on. Finally, top speed is 34mph in EV mode (with button, up to 41mph in "normal driving, but harder to achieve). Acceleration is quite slow compared to with the ICE. __________________ Evan E. Fusco, MD Seaside 04BC9/OEM EVb/NAV & auto-BT/XM Radio, CAN-View, Shark Fin, BT Stiff. Plate, Skid Plate & Strut Support

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08-22-2004, 09:44 AM	#3
Scorpio Join Date: Aug 2004 Location: Scotland Posts: 8 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Thanks for the info. We are UK based so we get the EV button as standard. 3 miles is a heck of a short distance though As I understand it, the battery pack is a stack of 130 or so D NiMh cells which are packed in a matrix of Serial/Parallel mode with temp sensors and a couple of cooling fans. It is quite simple to obtain NiMH D cells from surplus outlets and we can generally pick them up here in the UK for around 50p ($1) apiece in bulk. Therefore building a battery pack that will lie in the floor of the boot space and approx 4" deep, complete with temp sensors and switchable cooling fans is quite practical and certainly possible for a 2KWH unit to be built for around $700 or so. Could such an item not be installed in parallel across the existing battery pack? Does the CPU use voltage sensing to determine charge state etc and would additional capacity therefore be compensated for (in the same way that it senses a dying battery pack). I'm fully aware of all the safety precautions etc of working with NiMH and high voltages. Thanks for your help so far Scorpio

08-22-2004, 10:47 AM	#4
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 14,709 My Car: 2004 Prius Package: #9 Nominated 1 Time in 1 Post TOTM Awards: 0 Friends: 26	Yep, Scorpio, you're on track to how it's been done....I have additional information but I'm not sure how much I'm at liberty to share. Let me do a little research for you. Those who've added additional NiMH batteries that I'm aware of here have incurred costs more on the order of $1500-$2000USD. Additionally, as I began to suggest, there's some concern that an additional oil pump is probably necessary for prolonged EV mode to lubricate that system.

08-22-2004, 10:57 AM	#5
Scorpio Join Date: Aug 2004 Location: Scotland Posts: 8 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Many thanks Evan Any further info would be most helpful. Bear in mind that I am after extra range and not speed - 35mph is more than adequate for our needs. If the EU version includes an EV button then surely there must be sufficient lubrication already built in to the system. After all, Toyota doesn't say anything like 'Only use EV for 2 miles' or similar and they don't know that I don't live at the top of a mountain with a 10 mile downhill ride into town. Just a thought. We can buy those NiMH D cells very cheaply through military surplus routes - they come complete with solder tags etc. They just need testing before usage as 1 in 10 is generally faulty. Thanks again Scorpio

08-22-2004, 11:45 AM	#6
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 14,709 My Car: 2004 Prius Package: #9 Nominated 1 Time in 1 Post TOTM Awards: 0 Friends: 26	I think Toyota DOES believe that extended range EV could become a problem, they've even addressed it in this Patent Application The theories I'm familiar with suggest that some residual lubrication is almost always present, but with extended use could be depleted. It is not difficult to accomplish.

08-22-2004, 11:53 AM	#7
Scorpio Join Date: Aug 2004 Location: Scotland Posts: 8 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	That's interesting. However the EV button can be used when the vehicle has not been driven using the ICE - say after a lay-up of 2-3 weeks when any lubricating oil has drained or dispersed. So operation of the Electric drive would result in no additional lubrication of the ICE or the epicyclic gearbox. However my very limited experience of such gearboxes is that they are 'sealed for life' units and hold their lubrication internally. The problems could arise if the ICE was spinning during EV use - although then I would imagine that the crankshaft driven oil pump would circulate lubrication oil throughout the ICE. If I am not understanding the issue correctly please tell me. What other lubrication is needed other than ICE or gearbox? Thanks Scorpio

08-22-2004, 12:14 PM	#8
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 14,709 My Car: 2004 Prius Package: #9 Nominated 1 Time in 1 Post TOTM Awards: 0 Friends: 26	Hold tight Scorpio, I'll give you more data when I have 'permission'...hang in there.

08-22-2004, 12:19 PM	#9
Scorpio Join Date: Aug 2004 Location: Scotland Posts: 8 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Just re-read the application and I think that the vehicle actually handles the issues of lubrication by calculating the time since the ICE was last used and the various system temps and then using a map of the viscosity index of the oil (NOTE: ALWAYS use the recommended oils or else!!) to determine whether additional lubrication is needed. If it is then the Electric motor spins the ICE at idle speed so that the crankshaft oil pump circulates the oil for a predetermined time. It's interesting that earlier in the application they refute the use of an Electric oil pump because it lowers the engergy efficiency - however they then advocate the use of the ICE being spun by the Electric motor to circulate the oil - that's really not efficent and will accelerate wear on the ICE - imagine the energy being wasted. More likely is that as the ICE is a standard 'off the shelf' engine which already has a built in oil pump, then they decided to use the method of spinning the engine when lubrication is needed. But it's a bit unfair to claim in a Patent application that they chose not to use an electric oil pump because it would be inefficient. The only real question is whether the software algorithm in the ECU calculates the oil lubrication requirements over an indefinite time period - my guess is that it probably does for my previously outlined scenario - top of mountain downhill to town. Scorpio PS Sorry our posts overlapped - I'm sitting tight

08-22-2004, 12:19 PM	#10
bri1600bv Join Date: Aug 2004 Posts: 6 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	The Prius battery is about 2kwh of energy, but usually doesn't get drawn down to below 50 or 60%, from what I've read. 1 kwh should take you about 4 miles if at low speeds without stopping and starting alot. That's my guess anyway. I don't know if getting more batteries would be worth it. How would you get the software to recognize your new battery source and all? Otherwise it might start the engine as soon as the original pack gets down to 50% of charge.