I read so much about all kinds of battery types, Ni-Mh, Li-Ion and all the other fancy stuff, for BIG bucks. Has anyone ever considered good old Deep cycle Lead batteries? Even if it takes a small trailer to pull them. If I can travel 80 miles, just to pick a number, with a trailer and use no gas, that's just fine with me.
25pc deep cycle 12V batteries at 60 bucks a piece give me 300 Volts at a much lower price than any other battery. Throw in a small trailer and all that for $ 2,000.- for 12KWH or so.
Where am I going wwwwwrong?

 

Over the years a number of people have built EVs by removing the engine from small cars and stuffing the engine compartment full of deep cycle batteries. Search the internet and you will find them. It does work. The limitations seem to be that speed and acceleration is limited. Lead acid doesn't respond to load as well. Range of these vehicles tends to be less than 50 miles. In daily use, I'm not sure if the deep cycle batteries will last more than a year or two.

Maybe some other people have some first hand experience.

 

Battery power is significantly more effective on much smaller, lighter vehicles, which require less energy to move. Visit http://www.zapworld.com/. You have an interesting idea, which is the tried and proven American Way.

One thing to really consider though is this. If you plan to charge those batteries on a regular basis, and use a conventional 12VDC battery charger, you will need to buy a charger for each battery (or two batteries), to have time to charge them overnight. The overhead and time to do this is enormous. And if each battery charger pulls 10amps, you don't come close to being able to supply that kind of current in a conventional home.

 

Also, how are you going to recharge 12kWh of lead-acid batteries?

One reason why NiMH is so good for cars is:

They recharge in the same amount of time they discharge.
Whatever you take out in 5 minutes, can be put back in, in 5 minutes.

Lithium Ion is 2:1. What you take out in 5 minutes, takes 10 minutes to replace.

With Lead Acid, I forget, but the number is either 5:1 or 10:1.
The time required to recharge that many kWh of lead acid often = more hours than you have in a day. ( plus they are darn heavy )

 

I don't think a charger would be a problem. Keep in mind that I propose a 40AH battery (300V), which could be charged with a 1.5 KVA transformer 330V @ 4.5A. 440V would be a standard size transformer. Charge time is 1/10 of Ah's for 13 hours (overnight). Current limitation via thyristor and voltage regulating circuit. Here in FL. we pay approx 13 cents per kwh, x20 for a complete charge. That would bring the price per mile (assuming 50-60 miles , as someone had suggested) to about 4 cents/mile, or $ 1.20 for 30 miles. In gas that would be $ 3.70 for 30 miles.
Battery weight with trailer is probably in the 700lbs. range.
2 years of charging every night equals to 700 charge cycles, which I belief is the typical life expectancy of a NICAD. NIMH I don't know, but probably a lot better. I really don't know the number of charge cycles that can be expected from a lead-acid battery.
I am not saying that this is the way to go, it's just to get by until the price for the right battery drops to a reasonable amount. I heard rumors that oil companies have their greasy fingers in the battery pie. According to rumors their control may end 2010.

 

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Are you are referring to the patent that one of the oil companies owns on the GM EV1 battery technology as GM sold this outdated stuff to one of the big oil companies?

 

Thinking a bit more about this and looking at some of the available info on lead acid EVs, it looks like weight is the big drawback. Also, the higher voltage systems (and 300 volts is really high for an EV) get much better performance but the battery life, even with deep cycle batteries goes way down. The most successful conversions seem to be small pickups where you can add a hefty 100+ volt system and not affect the overall weight and aerodynamics that much.

One interesting alternative on the trailer idea: One concept proposed was a pure EV with a 50 to 75 mile range and an optional trailer that would have a diesel generator and power cord for longer range trips.

 

I have no experience with lead batteries, but a quick calculation (rough estimate only), shows that unless the battery lasts 4-5 years with 10.000 miles per year, it is not economical. Pure charge cost vs. gasoline at current price break-even is at least 3 years. Well, so much for lead battery.

 

The Lead acid batteries have shorter cycle life comparing to the NiMH or Li-ion.
Following is the battery life and cost data on the original Prius+ project in 2005.

PbA battery pack cost: $700
Approx. lifetime cycles: 200
Approx. pure EV miles/cycle: 10
Approx. $/EV-mile: $0.35/mile

Ken@Japan