Question of EV mode in PHEV conversion

[paulccullen]

Hi everyone,

I've had Coastal Dave's EV mode switch for a year now (pretty cool!), and am seriously thinking of doing a full PHEV conversion, but I have a question I can't find an answer to:

The current EV mode is pretty limited. speed < 35 MPH, power < 24 kW. This makes sense with the existing battery size, but:

*** Are these limitations increased in a fully charged PHEV?

Everything I've been able to google on PHEV prii says these EV mode limitations remain unchanged, but this would render PHEV no different from a *normal* Prius for freeway driving. I would hope that a fully charged PHEV would stay in EV mode up to, say, 60 MPH, 50 KW, dropping to the normal parameters as the battery level returned to normal Prius levels.

My decision to do a PHEV conversion pretty much depends on this ability.

TIA

[Cheap!]

<div class='quotetop'>QUOTE(paulccullen @ Dec 10 2006, 11:23 AM) [snapback]360049[/snapback]</div>

Hi everyone,

I've had Coastal Dave's EV mode switch for a year now (pretty cool!), and am seriously thinking of doing a full PHEV conversion, but I have a question I can't find an answer to:

The current EV mode is pretty limited. speed < 35 MPH, power < 24 kW. This makes sense with the existing battery size, but:

*** Are these limitations increased in a fully charged PHEV?
[/b]

No, you still have a <34 MPH limit for full EV. However with your PHEV second battery you will increase your over all KWH so you can EV longer. If you travel over 34 MHP you will have more of an assist so until you use up the second pack you'll get about 100 mpg. Once you use up your second pack you will just go back to normal. It is best to size the PHEV pack to be just what you use in a normal day. In my case 30 miles each day. However that is if you can afford it. For now I will start with a 10 mile pack and move up later. Most of my driving will be at highway speeds so you double the EV only range to figure I should have 20 miles each day at 100 MPG and the other 10 would be at the normal 50 mpg.

<div class='quotetop'>QUOTE(paulccullen @ Dec 10 2006, 11:23 AM) [snapback]360049[/snapback]</div>

Everything I've been able to google on PHEV prii says these EV mode limitations remain unchanged, but this would render PHEV no different from a *normal* Prius for freeway driving. I would hope that a fully charged PHEV would stay in EV mode up to, say, 60 MPH, 50 KW, dropping to the normal parameters as the battery level returned to normal Prius levels.

My decision to do a PHEV conversion pretty much depends on this ability.

TIA
[/b]

The problem is with the mechanical synergy drive system. The power split devise is designed so that both the ICE and the motors work together otherwise one side or the other have to turn at very high speeds. Your motor is rated to push the Prius above 80 mph, but the PSD prevents that. Is there a way around that? Not that I have seen.
Important note: Battery packs are considered bad once they can only hold 80% of the power of when they were new. Lead Acid batteries for this conversion hit that point at about two years. At a cost of $900.00 for the pack and you saving about $300 to $400 on gas over that time, you will be in the hole for a few hundred bucks when you have to replace them. You will never see a finical return on your investment unless the battery life increases or the price comes down. Of course you could just keep using the same batteries for a while since they still would have 80% capacity. A point to remember, thumbing you nose as foreign oil is priceless.

[paulccullen]

Thanks Cheap! I was hoping you would answer, since you seem to be "the man" for PHEV conversions here. Your detailed explanation is very enlightening.

So the ICE will still kick in above 34 MPH, but with more electric assist (until the battery level returns to normal HEV level) I guess that means that the <24kW limitation is extended. Sounds good.

Back in the mid '90's I converted a Geo Metro to EV. I had to replace the PbA batteries every 18-24 months. Sounds like it's about the same now. Hopefully by the time I get around to my PHEV conversion there will be better/cheaper batteries (altho' I've been waiting for this for over 10 years now )

[Cheap!]

<div class='quotetop'>QUOTE(paulccullen @ Dec 10 2006, 01:04 PM) [snapback]360077[/snapback]</div>

Thanks Cheap! I was hoping you would answer, since you seem to be "the man" for PHEV conversions here. Your detailed explanation is very enlightening.

So the ICE will still kick in above 34 MPH, but with more electric assist (until the battery level returns to normal HEV level) I guess that means that the <24kW limitation is extended. Sounds good.

Back in the mid '90's I converted a Geo Metro to EV. I had to replace the PbA batteries every 18-24 months. Sounds like it's about the same now. Hopefully by the time I get around to my PHEV conversion there will be better/cheaper batteries (altho' I've been waiting for this for over 10 years now )
[/b]

Wait no more. We are just waiting for pricing and availability. These are what we have been waiting for.
one:
http://video.yahoo.com/video/play?vid=c860...934330b.1249609
Two;
http://www.altairnano.com/documents/Altair...resentation.pdf

Now that you are impressed, and I know you are... I have tried to get Altairnano to work with me on getting these batteries so I could show what a PHEV with these batteries could do, but they never contacted me back as of yet. If I could get a full set for my Prius PHEV I would end up with a PHEV80 to PHEV100 or at highway speeds 160 to 200 mile range at 100+mpg.

Like I said, these are what we have been waiting for. After these come out, regular LI-Ion won’t cost near as much as everyone will want these instead. 12 year life, no explosions, they work in hot and cold temps. In the future look for cheaper conversions that are more simple to do.

[darelldd]

As Cheap points out, you do have the same mechanical limitations, and many of the electonic ones as well. EV mode with a bigger battery IS different than EV mode with the stock battery, however. You can demonstrate this difference to yourself by charging the battery to full. All green - as far as the car will let you charge. You need a nice long down-hill for this. Now that the car is full, accelerate briskly, and drive up to freeway speeds. You'll notice that the battery is used WAY the heck more than normal. The car will let the battery propel the car far more often, and at higher currents until you've taken the "top" off the charge. With a PHEV conversion, you enjoy that "full charge" feeling for quite some time.

<div class='quotetop'>QUOTE(Cheap! @ Dec 10 2006, 10:44 AM) [snapback]360068[/snapback]</div>

...you will be in the hole for a few hundred bucks when you have to replace them. You will never see a finical return on your investment [/b]

My hope is that the folks doing this - on the bleeding edge - are not doing it for financial gain. There are far more important investments that we can make, and for some, this may be one of them.

[paulccullen]

<div class='quotetop'>QUOTE(Cheap! @ Dec 10 2006, 11:58 AM) [snapback]360095[/snapback]</div>

Now that you are impressed, and I know you are... I have tried to get Altairnano to work with me on getting these batteries so I could show what a PHEV with these batteries could do, but they never contacted me back as of yet.
[/b]

Yes I'm impressed This sure sounds like the way to go. Altairnano does mention HEV-to-PHEV conversions, they even have a picture of a Prius but no details. Too bad they're not very communicative, I'd love to know when their batteries will be available to the public for do-it-yourself projects.

And no, I'm not in it for the money. I lost financially on my EV conversion 10 years ago, and I'm sure a PHEV conversion won't be cost-effective either. But I just watched "An Inconvenient Truth" and "Who Killed the Electric Car", and I'm ready to do what I can to save the planet.

[Cheap!]

Do you think that maybe we should see how many people we could find that want to do a conversion with Altairnano batteries so we could pool together to make a proposal? I could forward that on to my contact as well. Maybe with more people interested, we could get a quicker response?

What do you think?

[sub3marathonman]

elecblue has also done and completed a conversion of his Prius. He used a more exotic battery charger / inverter, and fewer batteries. His conversion is explained at http://www.eaa-phev.org/wiki/GrayPerl. Apparently mrbigh has also completed a conversion, but I haven't heard the details yet.

Also, the batteries will not necessarily have to be replaced in two years. That is somehow getting stated as a fact, but it really depends on the batteries. The calcars team used relatively cheap batteries to experiment on, and they apparently went bad after a couple of years or maybe even less time. The better batteries will be more expensive, but in the long run are worth it. For about $1700 you might expect to see five years of battery life. For the PbA batteries you really need to limit the discharge to 30% too (that's 70% remaining), otherwise the lifespan of the battery is shortened. That is what is so upsetting about PbA batteries, you're carrying around a huge amount of Pb just so the batteries can have a reasonable lifetime. It is also similar with NiCd batteries, where you might get 100,000 cycles at 15% discharge but only 2000 cycles at 80% discharge.

I would be interested in the Altairnano batteries too, but it is unknown when they would be available, how much they would cost, or what their projected lifespan would be. If their batteries are as great as they say they are, I think a lot of people would be interested in converting their Prius.

[Cheap!]

<div class='quotetop'>QUOTE(sub3marathonman @ Dec 10 2006, 10:35 PM) [snapback]360247[/snapback]</div>

I would be interested in the Altairnano batteries too, but it is unknown when they would be available, how much they would cost, or what their projected lifespan would be. If their batteries are as great as they say they are, I think a lot of people would be interested in converting their Prius.
[/b]

Life span for the Nanosafe batteries have been tested to 10 or 12 years in charge cycles. Now whether or not the Titanate material will break down in 7 years is unknown.
You can buy 28 modules or a pack of about 35kwh for your conversion for $45,000. Of course that will include a truck you would have to throw away. However, the batteries by them self should be a good deal less. We should know in January or February at the latest because of page 21 in this presentation.

[paulccullen]

<div class='quotetop'>QUOTE(Cheap! @ Dec 10 2006, 02:18 PM) [snapback]360130[/snapback]</div>

Do you think that maybe we should see how many people we could find that want to do a conversion with Altairnano batteries so we could pool together to make a proposal? I could forward that on to my contact as well. Maybe with more people interested, we could get a quicker response?

What do you think?
[/b]

Mmmmm. That's a catch-22 question. I'm with sub3marathonman, I'm certainly interested in using Altairnano batteries, but when (or whether) I would use them depends on the price...