question about lead acid batteries

[Alpo]

If you were attempting to build an electric car, and you were going to use standard 12-volt lead acid batteries, would it make more sense to get regular car batteries, or deep cycle marine batteries?

 

I'm reading a novel. This is fiction. This is all made up. I am not building an electric car.

 

The way the book reads they're just buying car batteries. It just seems to me that deep cycle marine batteries would be a better choice.

 

This is a - what do they call that - dual power(?) car. The car will run on electricity from the storage batteries. They will also have a four-horse four-cycle gasoline engine hooked up to a charger. When battery A is run down they switch over to battery B, and put battery A on the charger.

 

That just seems to me that the deep cycle would be a better choice. Car batteries, as I understand it, are not designed to run them all the way down before you charge them back up.

[Sgt. C.J. Sabre, SASS #46770]

Deep Cycle would be better for that. Deep Cycle batteries are designed for constant draw, like running a trolling motor, while Car batteries are designed for a short burst of power followed by a much smaller draw and constant charging.

[Finagler 6853 Life]

Using either battery wouldn't be effective in a car.  By the time you get enough battery power, it would weigh several tons.

[Alpo]

They started with a little bitty Renault, and then stripped as much weight away from it as they could.

 

It was a "proof of concept" college thing, only had to go 20 miles.

 

27 minutes ago, Finagler 6853 Life said:

By the time you get enough battery power, it would weigh several tons.

That was one of the problems they had. The guy thought that they should have three sets of batteries. When the first one went dead, put it on the charger and run on the second, and when the second went dead hook it into the charger while continuing to charge the first and by the time the third set was dead the first one should be back up.

 

But they didn't have the room and they didn't have the ability for the extra weight.

[sassnetguy50]

6 minutes ago, Alpo said:

They started with a little bitty Renault, and then stripped as much weight away from it as they could.

 

It was a "proof of concept" college thing, only had to go 20 miles.

 

That was one of the problems they had. The guy thought that they should have three sets of batteries. When the first one went dead, put it on the charger and run on the second, and when the second went dead hook it into the charger while continuing to charge the first and by the time the third set was dead the first one should be back up.

 

But they didn't have the room and they didn't have the ability for the extra weight.

How many hours did they have?

[watab kid]

9 hours ago, Sgt. C.J. Sabre, SASS #46770 said:

Deep Cycle would be better for that. Deep Cycle batteries are designed for constant draw, like running a trolling motor, while Car batteries are designed for a short burst of power followed by a much smaller draw and constant charging.

what he said 

[Alpo]

1 hour ago, sassnetguy50 said:

How many hours did they have?

To do the 20 miles? It was a race. Whoever got there first. There were four cars. One was steam powered and the other two were propane powered.

 

Both of the propane powered cars did not make the 20 miles, because (the book said) propane burns much hotter than gasoline and they did not take that into account when they converted the cars. Both cars overheated.

 

And it looked like the steam car was going to win but he had to play like the tortoise and the hare. Waited until the last second, while the electric car - actually coasting downhill now because the batteries were all dead dead dead - and when he romped on it to make that quick rush across the finish line and beat it, he blew the packing out of his boiler.

 

Let's hear it for Dave White And The Electric Wonder Car!!!

[DeaconKC]

Back in the 70s a neighbor built an electric from plans in Mechanics Illustrated. Deep cycle batteries is what he used. Neat little car, but he couldn't get it licensed!

[Imis Twohofon,SASS # 46646]

Lead acid batteries have been used in material handling applications for 75 years. The biggest problem was battery charging and battery life. Lead acid batteries need time to cool down after a charge or they will discharge very rapidly, so you actually need three sets of batteries. Also higher voltages will provide more power and longer charge life than lower voltages. In the early days resistance coils were used to slow the vehicle down, for control. Later came silicon controlled rectifiers and then AC controllers each of which gave longer battery and charge life. The weight of the battery was used to counterweight the lift truck allowing greater capacity. Modern electric vehicles use other-than lead acid batteries Lithium, etc where weight is a problem. Today the AC drives are hugely more efficient than a stack of resistors, but fires and charge facilities are problematic. 

The author had his tech back a$$wards on propane. it burns cooler than gasoline, because it contains less BTUs. Regular engine cooling systems should keep a propane powered engine properly cooled. Most folks wouldnt know the difference, it is a story and authors often change the physical laws of the universe to fit the story.

 

Imis

Edited February 3 by Imis Twohofon,SASS # 46646

[Sedalia Dave]

 

 

[Sgt. C.J. Sabre, SASS #46770]

4 hours ago, Imis Twohofon,SASS # 46646 said:

it is a story and authors often change the physical laws of the universe to fit the story.

 

Imis

Say it ain't SO! Alpo's going to have a conniption.