[david85]

No, that doesn't quite qualify for a smack, I'd preffer getting it all as well.

There are compramises in battery chemistry, and more expencive batteries can deliver better life,

But this really comes down to bit of a dilema with getting an electric car. EVs can easily outlive most any other ICE powered cars, but despite being simpler, and having fewer moving parts, the purchace price is still higher. This is why I went all out with the idea of building an electric car, since making one cheap enough to compete with a civic is just not realistic, I may as well build one to last (or at least try).

Lithuim cells have come a long way in the last few years, but frankly, its too soon to tell how long many of them can live, because in most cases, they are still within the theorietical shelf life.

But this is an interesting read: http://www.lionev.com/Battery_Pricing.html

If you havent heard of LoinEV.com yet, they are aiming to convert the hyndai santa fe, accent, and ford ranger to electric for sale to the general public, but they will also sell battereies (and BMS) to anyone whoe wants them (minimum order is 10KwH). They are still quite new, and it remains to be seen how succesfull they really are, but I sure hope they can pull it off.

They are one of the few sources of prices on advanced battereies, and you can see the difference between low purchace price vs high performance and long life (if you navigate the website, you will find well detailed price lists on differend chemistries, and systems)

These guys are also pushing the limit in warantee as well, the two high end batteries are offered with a 7 year coverage, or lifetime coverage if you buy the BMS (battery management system) as well. In the case of lifetime warantee, it qualifies for replacement when the cells can no longer return 50% of rated capacity.

Personally I would be tempted to go with the high end battery, even though it could cost $30k and up, but thats just me. Although I would probably go off the deep end, and try to fit a 100Kwh pack in the car (in theory, that could mean a 1000 mile range, you don't want to know how much a 100Kwh pack would cost though).

[pandaran]

XD Woo! 1000 mile range? I love it!!

So, $373 per KWh is the cheapest lithium battery pack on the market according to them. That means if my hypothetical car weighs 1000kg, then I'd get a little over 3 miles from one battery pack. Is that right? And then you have to add in the weight from the batteries, motor, and whatnot, too, right? (So many numbers to take into consideration! My brain hurts!)

[david85]

The distance you can travel is based on many factors (weight and drag mainly), but it is possible to estimate by calculation.

Using your example, it would mean a distance of 3 miles per kwh of energy consumed. In the case of the solectria sunrise, it was equipped with a battery pack that could store up to 21 kwh's of energy, so 21 kwh x 3 miles per kwh = 63 miles of range of that example. (lionev's minimum order size is 10 kwh)

In reality though, the sunrise was documented returning a range of 375 miles under favorable conditions, but If I were to take this and run with it, we could get a range of 1780 miles with a 100 kwh pack (if we assume that it can deliver 17.8 miles per kwh of energy, and that the car weighs the same).

Now for the reality check.

The solectria sunrise was a light (for an EV) and arodynamic car, and under more realistic urban traffic conditions, 300 miles of usable range was also observed. At 60 MPH, the range was reduced to 200 miles. Heres some more info in the sunrise: http://en.wikipedia.org/wiki/Solectria_Sunrise If anyone else has some info on this car, please chime in.

Weight of all those batteries are also of some consern, as the heavier the car gets, the less miles per kwh's (MPKs) it returnes (same applies for higher speed), simply fitting them all in could also be a challenge. But this is where it comes back to energy density of the battery itself, since we are getting close to having batteries that allow us to have our cake, and eat it too.

In the case of the lithium sulfur battery shown here: http://sionpower.com/technology.html

A 100kwh battery would only weigh approximately 286 Kg or about 630 pounds, and we still have to consider the wieght of the battery case(s), wiring and electronics. (Sion battery = 350 wh/kg)

But with such a long range, why would anyone really need more than 300 100% discharge cycles (theorietical service life of this example would be half a million miles)?

And before you ask, I have no idea what the projected price of sion's lithium battery will be if it ever gos into mass production, but its still nice if we dare to dream sometimes....

[david85]

I have some updates to report.

I have been in contact with a lithium polymer battery builder for the last week. Their product is the same one that was used in the Impreeza EV race car mentioned on annother thread.

Kokam (korea) is the authorized manufacturer of these cells (older, cheaper LIon are also available), and they will sell to the general public. Some of you may be aware that kokam is already well know as a supplier of lipo cells for high performance RC batteries. (If you see an electric RC plane climb strait up like a rocket, chances are it is powered by kokam cells)

The cost is still not very good compared to lead, but lithium polymer batteries could yield a lifespan of up to 10 years, and they are zero maintainence. The cost, as verified from two sources is at U$1600/kwh.

To give a basic picture of what that would be for a real car, the sunrise had a battery of 21kwh, so $1600x22= $33600. Not cheap I know, but the sunrise had a range of over 300 miles as documented on several ocasions (with heavier batteries) if the size of the battery would be scaled down to the size that most conversions have, the cost would be more comparable. BMS is extra. The estimated weight of such a battery would be 126 Kg or 276 lbs (again, BMS would raise that slightly).

In addition, the cost of the battery continues to come down, and discounts are available for high volume purchaces, I have yet to verify how much these discounts are, but as some one from ProEV.com told me via Email, the more you get, the better the price. There has already been a cooperative purchace of thundersky batteries, and this could be a way to get these at a lower price.

[RevDon]

Falcon EV is now selling wheelmotors! Take a look, they'll give you something to think about

http://www.falconev.com/

[david85]

Could be promising, so far most wheel motor builders seem to think that they are worth their weight in gold, and once again the chinese save the day. I'll have to keep an eye on this, maybe they can be ordered in a larger size, I've got to find some specs on these things........

[gregb]

Hello first post,

So with the talk on battery power and weight, can we calculate what the weight to power is of batteries commonly used for ev's and compare it with the weight to power of the lithium batteries? Then do a cost comparison to figure what will be the better buy.

I expect either there is a chart somewhere (which would help me look at battery comparison) or this question will be overlooked.

Love the forums

[david85]

gregb, welcome to the forum, I've only been here for about a month myself.

There are many charts out there on the internet, but I stopped paying attention to them a couple of years ago, things are moving too fast for such info to stay current.

The standard for costing a battery is typically in terms of $/wh, watt hours being the measure of the energy storage potential

To get the $/wh rating of a battery you really have to get prices from the battery supplier directly, which is not a problem with lead acid, since they are available at the retail level all over the place. Getting prices for nickel, lithium or other more advanced batteries can be challenging though, since many of them are still at the development stage, and most would rather not reveal their prices to some one other than a mega automaker.

And then it gets more complicated when volume pricing comes into the picture. I suspect lead acid is still the cheapest of them unfortunately, if purchace price is your main consern.

The only prices that I have been able to verify so far, are related to lithium batteries, since they are my personal favorate for this project (hence thats what gets most of research focus). I'll post what I can for now

Kokam/worley cells:

Energy density: 160 wh/kg (varries by cell application)

Cost: $1.60/wh (this is for lithium polymer, not the older lithium ion)

cycle life: 800-1200 @ 80% DOD

calender life: ~10 years (no proven tests, just the claim (expect a minimum of 5 years)

a123 Lithium Iron Phosphate spiral cells:

Energy density: 108 wh/kg

cost: : ~$0.85/wh

cycle life : over 1000 @ 100% DOD

callender life : unknown, lithium iron phpsphate is only a few years old, but it should perform better than the older lipos

There are many other factors to consider, but these are the ones you want to look at when figuring out overall cost of ownership. hope that helps.

If some one else wants to chime in with some data from their EV, please feel free to do so, prahaps we can compile the data later on a different thread.

[david85]

Chiba, Japan? wow, this is a global forum!

The nanosafe batteries are similar in energy density to NiMh, according to altair's claims. This page shows the performance graph: http://www.altairnano.com/markets_amps.html

You are correct that phoenix motor cars is using these batteries, and more recently, these guys in the UK have jumped in too. http://www.lightningcarcompany.com/

The lightning car has the potential to set a new standard in every way imaginable, by using PML's wheelmotor (Hi-Pa drive) powertrain, the car will possibly have the best overall performance in terms of traction as well as accelleration and braking.

And then there's the eliica supercar, I'm betting you have heard of it.......(don't think they are using the nanosafe battery, but it is still direct drive with lithium batteries)

But as far as altairnano's batteries go, I can't find much in the way of pricing or even projected long term cost. The best estimates I have seen so far are purely speculative and assumes that the technology will be heavily subsidized. The cost for the battery pack per truck is thought to be somewhere between $40k and $80k USD. Its not out of line if the cost can be driven down, this is still a very new battery after all.

EDIT: PS, I don't even know if they will sell them to end customers.

[david85]

If you don't mind my asking, where are you getting your hub motors? I have had a helluva time trying to contact potential suppliers of suitable motors, PML Flightlink was so far the only one that took us seriously, but the cost was just too high for this application(~90K USD).