Which electric car batteries do you need for your conversion or other electric vehicle?
There are several different chemistries now available (some more available than others!). We'll talk about lead acid golf cart batteries, nickel-based batteries, and a couple of different lithium ion batteries - including LiFePO4, my new personal favorite - and what kind of batteries NEDRA drivers put in their electric cars these days.
By far the most popular and widely available electric car batteries are the deep cycle lead acid batteries.
In the second edition of "Build Your Own Electric Vehicle", the author says lead-acid batteries work just fine for an electric car. "Contrary to those who say you'll need a different type of battery before EVs are suitable at all," he writes, "today's conventional lead-acid batteries of the deep-discharge variety are perfectly adequate for your EV conversion." (p.177)
What this means in practice is that you'll need to choose between extra batteries or the ability to carry more passengers. If my observations of freeway traffic are any indication, we didn't really want the passengers anyway.
"(Regarding electric cars) the news IS the batteries. Instead of 30 miles range (as with lead), we get 80-100 quite easily. And instead of 24 months, we can get 10 or 12 years from them. They are a miracle."
Jack has put these LiFePO4 cells in his DC conversion, with a motor from NetGain, and also in an AC conversion with a motor from HPEVS. Each system is getting 80-100 mile range. With lead, there would be a marked difference between the range he could get from his DC conversion (less!) and his AC conversion (more!) under normal driving conditions.
You've probably heard that we don't really have NiMH EV batteries anymore. You can get NiMH batteries, but the large format NiMH that is suitable for electric cars is presently a patent hostage being held by Chevron.
Doug Korthof, someone you might have seen in the film Who Killed the Electric Car?, talks in this video about his Toyota Rav-4's NiMH battery pack, which gives his car around a 100 mile range, like lithium, and has lasted over 100,000 miles so far on the original batteries, by the way. Lithium is great, but 100,000 miles? No wonder the gas companies killed the NiMH electric car.
Note on the Toyota hybrid NiMH batteries: they are not designed for deep discharge, if you find some and decide to put them in an electric car. They're more like the SLI lead-acid batteries than the NiMH EV batteries. The hybrid batteries will die young if pressed into service as EV batteries.
There are other nickel chemistries, particularly Ni-Cad, that work great in electric cars, too. Saft is the biggest maker of these that I know of. Saft only sells NiCads in the US to fleets now, but you can sometimes salvage Saft NiCad STM-180's from those electric buses and vans...
...and get a set of very inexpensive, excellent EV batteries that will last a very long time.
If you go this route, keep in mind that NiCad batteries have KOH electrolyte instead of acid, you'll want to recycle the batteries at the end of their EV life (no cadmium in the landfill, please!), and the NiCad charging profile is a little different than lead or lithium.
John Wayland - aka Plasma Boy, don't ask - has had lead acid batteries in his electric race car, the White Zombie, for a long time. But not anymore.
Recently, he's made NEDRA headlines by installing lithium polymer cells in that quick little DC powered Datsun (two DC motors, actually) and driving from Portland to Seattle and back (no, not without recharging!). Mr. Wayland is slightly notorious for his lead foot and his stereo, so I'm thinking you can credit the batteries for the long range.
From NEDRA news, June 2011: "The Zombie has a range of just over 100 miles with it's Dow Kokam Lithium Polymer battery pack and will be making three short charge stops to juice up along the way....who would have thought you can drive a street legal 10.2 second electric car over 100 miles on it's own power?"