GM's Electric Vehicles

Lithium-ion Battery Charging & Advantages – PowerTech Systems

Lead Acid Battery vs Lithium | Lithium Iron Phosphate (powertechsystems.eu)

Keep in mind that chart is from 2013, li ion technology has advanced quite a bit while lead acid has not. Also keep in mind the greater weight of the lead acid batteries will negatively affect range. Lead acid batteries also have much, much shorter lives.

Lead acid batteries were used in the very early versions of GMs EV1 gave it a 75 mile range in a very small 2 seat car. The Nimh batteries increased that range to about 125 miles in the same physical package and decreased weight from 1500 lbs to about 1000 lbs. That was likely the last EV to use lead acid batteries.

Right, right. I was born in 74. I didn’t have power tools in the 80’s, so I was not aware they made them with lead acid. I do remember NiCad. And I suppose the 2 seater Citicar or whatever it was called probably had lead acid batteries. Still, I imagine there’s a good reason that no one (that I’m aware of!) is really still pursuing lead acid batteries in EV’s or power tools now. That I’m aware of…:grin:

I also remember Dad always bought the corded tools because he said the batteries didn’t last!

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I tried the rechargeable things, batteries never lasted, every time which was probably not frequent enough, useless. So my go to tools are electric cords, or my screwdriver that takes double aas

And a new battery pack cost half as much as the whole tool right? One of the biggest advantages of lithium has been that proper charging is required, and over discharge protection is required. Overcharge and it can rupture and cause an injury or lawsuit, over discharge a few times and it’ll be ruined in a matter of weeks. Technically a good NiCd battery can have more longevity than lithium if the cells are of good quality, and proper charging is done (it’s harder than for lithium) and proper over discharge protection is done. Having all 3 of these things together in a product, be it lead acid, NiCd, or NiMH almost never happened. Lead acid requires maintenance cycles during storage or it will either go bad due to sulfation or positive plate destruction from over charging.

Lead acid is far cheaper than lithium, about half the cost per kW I believe, but figure that you get 1/4 the capacity for the same weight. So you would be spending 1/8 as much money for a battery pack that gives you 1/4 your original range. Imagine a big heavy 200 mile range Tesla only being able to go 50 miles!

The 1993 Dodge Caravan TEVan (electric vehicle) had nickel-iron or nickel-cadmium batteries (wet cell) that were reported to weigh 1800 pounds. The batteries were expected to last 20 years. Top speed was 70 MPH, range 80 miles. This was developed in response to California’s first effort to rush-to-market the supply of electric vehicles. After manufacture spent an enormous amount of money on these projects, CA decided EVs would be impractical at the time. GM claimed to have spent 1 billion dollars on the EV1 project.

Chrysler’s Electric Cars and Minivans: TEVan, EPIC, ENVI, and more | Allpar Forums

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You are looking to the wrong chart so your math is off. You need to look at the volume chart in the first reference. After all, you are going to fill up the battery tray with as much lead acid batteries as you removed li-ion, right?

Those numbers are lead-acid - 25 to 100 W-hr/liter and prismatic li-ion is 325-425 W-hr/liter or cylindrical cells 375 to 510. So the ratio is 6:1 with a prismatic cell and 7:1 with a cylindrical cell.

Additionally the discharge and recharge efficiency of Li-ion batteries is roughly 95% while lead acid is more like 20-25%. This makes acceleration efficiency better as well as improving re-gen braking energy being returned to the battery. Those are critical to the range of electric cars.

https://www.large.net/news/8bu43pr.html

Using that same chart the volumetric and gravimetric energy densities are fairly close. Picking the middle of the bubbles gives roughly 3.3 for gravimetric and 3.75 for volumetric. So yes filling up the same space in a lithium ion EV would be 1/3.75 times the available energy, and it would result in a slight weight reduction of 0.88 of the original.

In designing an EV I believe weight is the primary limitation. I think I could fit 60 batteries in the back of a pick up truck. It would have 60kW-hr of capacity but weigh 3600 pounds just from batteries. It would fully load a 3 ton pickup truck. There would be no extra room for cargo. It would make the truck weight about 1.75 times as much, so it would need 1.75 times as much motor power for city stop and go driving to match unloaded gasoline performance. It would have regenerative braking to regain a lot of the energy spent accelerating in stop and go traffic, but I think you would be optimistic to recapture 70% of the energy due to energy conversion losses combined with the 85% cycle efficiency of lead acid. You would also be cycling (wearing out) the batteries, and here in the mid west with cheap electricity, the cost of lead acid storage is about double what commercial power costs. So 2/3 of the operating cost is still being lost with regenerative braking when you consider electricity costs and battery storage cost together. So having a lead acid EV that weighs twice as much compared to gasoline power ends up not saving very much in the end. But for cruising on the interstate, you could go up to about 3 hours at 60 MPH and it would only cost you about $5 in electricity (at 10 cents per kwh) and $9 in battery costs. Lead acid purchased in bulk may be a bit cheaper than $9. How much wind resistance there is and the speed traveled makes a huge difference here. It’s hard to come up with a number for range. I picked 15kW (20HP) for cruising at 60. edit: I said 4 hours at 60 MPH but I forgot to account for lead acid’s capacity loss due to a high discharge rate.

No, it’s battery cost.

Would you be willing to drive my example 8000 pound electric pick up truck monstrosity around texases? The batteries are cheap! Complete replacement would only be around $6000.

Oh, you mean building a lead acid EV. Not an option today, for sure.

Lead acid EVs have been around for longer than IC powered cars. They lost out to gas powered cars 100 years ago. That ship sank long ago.

It took a revolution in battery technology and solid state variable frequency drive technology to put EVs back into contention with IC powered cars.

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