N600 vs. VW Bug?

[kickflipjr]

Those micro cars are rediculous. I always watered an isseta (aka the urclemobile).



I saw one at a carshow. It was very tiny.

[Matt Timion]

Originally Posted by kickflipjr

Those micro cars are rediculous. I always watered an isseta (aka the urclemobile).



I saw one at a carshow. It was very tiny.

When I took my bumper in to be re-chromed the guy thought that I had one of these cars.

"The door is in the front, right?"

*hits head* "I'm a geek sir, not a dork!"

[GasSavers_Ryland]

one of the ideal cars for an EV is the VW rabbit, the kits that have been made for converting them were at least at one time, about 10 years ago, extreamly commen, I have not checked in to it, but I would suspect that there is still alot of information, and parts around, they are also a solid enough vehicle to be able to handle the weight, and have enough space for batteries, and if you want to trade your n600, I have a very nice 2 door rabbit that is missing most of it's engine, but has a reasonably solid body... ok, I'll toss in a 2nd one.
but really, VW rabbits, and geo's are most likly going to be the most commen conversions, so buying things like addaptor plates for motors are going to be cheaper.
also for batteries, I would go for a few battery packs from a hybrid, NiMH batteries, already built in to a pack, used so they are cheaper, and tests show they are good for 100's of 1000's of miles in a hybrid.
beetles are not ideal because of their lack of space for batteries without pushing the weight distrabution way way off wack, n600 is not ideal because I want one! wait... that is not a good reason, but really, they get good mileage as they are, and if you are going to modify it, put a really small water cooled engine in with fuel injection.

[The Toecutter]

Using batteries from junked hybrids is not recommended for the following reasons:

-they are designed for shallow discharges
-their management system is tailored towards a hybrid application
-their AH size is so small and voltage so high your only reasonable option is to connect 5+ packs in parallel
-NiMH batteries are prone to problems being charged in parallel!
-$EXPENSIVE!$

Mind you, there are people that have done it. I know of a Lotus 7 replica using Prius battery packs obtained from junkyards. The builder spent many hundreds of hours finding a way to build a management system for them and a reasonable means to charge them, and his range is short(~10 miles IIRC) due to the batteries not being tolerable of deep discharges.

This is not to say NiMH is a bad chemistry. In fact, in NiMH batteries designed for deep discharges and pure EVs, they have shown esxtraordinary performance, cycle life in excess of 1,700, 150,000+ mile life in Toyota RAV4 SUVs with no capacity degredation yet(It is theorized they may last 300,000 miles, but no vehicles I read of have more than 150,000 miles of use yet), 120 mile range in Toyota RAV4 SUVs and 200 mile range in early Solectria Force sedans(I'm not talking about the ones with smaller battery packs that were sold to fleets), and according to ECD Chairman Robert Stemple, $150/kWh in mass production(20,000+ cars per year). They weren't perfect either. A major problem was overheating during charging, in which EVs in 100+ degree weather after being driven hard would need to run their air conditioning and have the cool air ducted to the batteries to cool them while charging. Overall, they were ready for consumer grade EVs, with realistic 150-200 mile ranges.

But Chevron Texaco is sitting on the patent. They're charging $1,100+/kWh for use of the batteries in today's hybrids, and restrict the max AH size of the modules which effectively prevents them from being used in plug-in hybrids and pure EVs(remember, NiMH doesn't like being charged in parallel! It is not practical to string together 4 or 5 370V opacks, either). This oil company's price gouging of this battery is responsible for roughly $1,000 of the price premium on hybrids like the Toyota Prius, and has helped stifle pure EVs greatly.

[Sludgy]

NiMH batteries were an important step towards practical EVs. But lithium batteries don't infringe the NiMH patent. There are lots of different lithium battery chemistries, and I don't think they're all patented.

One of the most promising is Valence Technologies lithium phosphate chemistry. It uses cheap raw materials, and the batteries are much safer than batteries with nickel and cobalt cathodes. But I heard that Ontario Hydro has filed a patent suit against Valence.

Ontario Hydro is a big part of Canada's energy complex, but they're not an oil company. Do you think Ontario Hydro is trying to suppress lithium phosphate battery technology?

[The Toecutter]

NiMH batteries were an important step towards practical EVs. But lithium batteries don't infringe the NiMH patent. There are lots of different lithium battery chemistries, and I don't think they're all patented.

You are correct in your thoughts.

The big drawback with lithium, otoh, is that it needs a very complex management system for charging. Most lithium batteries on the market pose a fire risk during charge. Further, they are not as cheap as NiMH. Even in mass production for automotive volume, you're looking at $250-400/kWh, compared to $150-250/kWh for NiMH. A midsize car with 200 miles range and no special attention to aerodynamics will need about 50 kWh of battery(Or about 30-35 kWh WITH special attention to aerodynamics). Current lithium technology, even with mass production for millions of EVs, would only be feasible for upscale markets or shorter range cars(~120-150 miles instead of 200+ miles), while NiMH had the potential production cost barriers broken. NiMH also have much higher cycle life. Lithiums will last about 4,000 cycles to 20% discharge, 400 cycles to 100% discharge, while Ovonic NiMH will last 1,750 cycles to 100% discharge. So a lithium battery could be expected to last ~150,000 miles, NiMH could be expected to last over 300,000 miles, discounting shelf life.

To lithium's credit, it has double the specific capacity of NiMH. Twice as much storage per pound of battery.

Even with the drawbacks, there is no excuse why a 200 mile range lithium battery EV can't be produced with a $25,000-40,000 price tag. It all goes back to production volume. Even with a premium lithium battery, it would still be cheaper to run than most gas cars would the batteries be mass produced for automotive application.

One of the most promising is Valence Technologies lithium phosphate chemistry. It uses cheap raw materials, and the batteries are much safer than batteries with nickel and cobalt cathodes.

They've basically gotten rid of the big safety hazard during charging: fire. This is at the expense of peak power output. Currently, they are around $1,000/kWh. Mass production could yield $350-500/kWh. An 800 pound pack would be doable for a car with 50 horsepower from the motor. Slow, but still highway capable. It would be difficult justifying such a premium for that type of performance though. In this regard, Sony 18650 Li Ions, Kokam Li Poly, ect. are much better.

But I heard that Ontario Hydro has filed a patent suit against Valence.

Ontario Hydro is a big part of Canada's energy complex, but they're not an oil company. Do you think Ontario Hydro is trying to suppress lithium phosphate battery technology?

I know very little about this case relative to what I know about the NiMH case. It is certainly a possibility, but I cannot yet say.

[Sludgy]

I gotta believe that lithium battery prices are going to plummet at some point. Lithium, iron and phosphate are cheap compared to nickel, cobalt and misch metal used in competing battery technologies.

On a cost-per-mole basis, the raw materials are about the same as lead. Once mass production starts, I forsee lithium batteries at the same cost per kwh as lead acid.

[The Toecutter]

But Li Ions need a very complex management system. That is what will keep them at $250-400/kWh in mass production.

Raw materials are an insignificant factor of the cost relative to design if they could be made in those volumes.

If we develop a Li Ion that's hardy enough never to need manageemnt, OTOH, then yes they could be like GC batteries.

But even at $250-400/kWh would it be mass produced, it's still capable for a mass market road going EV.

[Sludgy]

Yes, lithiums require managment circuits to prevent overchargingsome cells and undercharging others, but we're talking only 1 chip per battery. One these things are in mass production, we're talking about costs about the same as a memory card.

Valence Technologies already has integrated a charge managment circuit into large lithium batteries. They're not a significant cost obstacle for a $20K EV imho.

[The Toecutter]

Have you ever seen a battery regulation system? It's a stretch to say it's one chip per battery. Take Manzanita Micro's shunt regulators for lead acid and large NiCds, for instance. The basic materials cost alone is at least $15. Hand made, these regs retail for about $40 each. In reality, a mass produced management system acceptable for mass consumption(ie. 0% rate of failure) is going to cost about 1/3 of the battery pack. Hand made, a regulation system can actually outprice the battery pack itself(especially in the case of finicky lithium batteries).

As viable and workable as the technology is, it is very difficult to properly implement it. If we put one tenth as much into EVs as what went into oil subsidies, we'd have a battery/monitoring system combo that would be fail proof and affordable(ie. Li Ion batteries plus management ~$300/kWh). But we don't. It's possible and has been demonstrated with other chemistries, but no one has built one for Li Ions yet. AC Propulsion made some significant inroads, arguably has come very close and is certainly in the realm of acceptability.