Help with several battery questions please

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nduka-san
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TL;DR
i dont understand batterys that well and would like to know how they work other
i know that batterys are made of a compination of chemicals since i took honors physics but i never really learned how they are made just what theyre made of

2 how large of a battery would be needed for a small tractor with a weight of 300 pounds in this hypotheical scenarior its related to another topic

3 how bad are batterys for the envionment with their chemical cocktails
 
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nduka-san said:
Summary:: i don't understand batterys that well and would like to know how they work other

i know that batterys are made of a compination of chemicals since i took honors physics but i never really learned how they are made just what theyre made of

2 how large of a battery would be needed for a small tractor with a weight of 300 pounds in this hypotheical scenarior its related to another topic

3 how bad are batterys for the envionment with their chemical cocktails
Numbers 1 and 3 you hould be able to Google and learn about the different types of batteries. Let's take #2. It's all about how much power you want it to have and how long you want it to operate between charges. A typical small garden tractor weighs about 600 pounds, and has a 25 HP gasoline engine. So let's say your 300 pound tractor would need at least 10 HP. 1 HP = 746 Watts, so you would need an electric motor capable of producing about 7500 Watts, or 7.5 Kilowatts. Now how long do you want it to run between charges? Let's say 4 hours, but you can decide that. Then you need a battery with a capacity of 7.5 * 4 = 30 kWh. How much would that weigh? A Tesla 85 kWh battery weighs 1200 pounds, so a 30 kWh battery will weigh about 400 pounds. Do you see the problem? To run your tractor on a battery, you will either need less power or less time between charges.
 
phyzguy said:
A Tesla 85 kWh battery weighs 1200 pounds, so a 30 kWh battery will weigh about 400 pounds. Do you see the problem? To run your tractor on a battery, you will either need less power or less time between charges.
and since it will weight more it will need more time between charges for driving it because of the battery weight.

also what about if it was a tractor but it weighed a lot less for example let's say it weighed 200 pounds because rn that's the average estimation for my project also would u have any recemendations for motors? that are ood at saving electricity
 
nduka-san said:
also what about if it was a tractor but it weighed a lot less for example let's say it weighed 200 pounds because rn that's the average estimation for my project also would u have any recemendations for motors? that are ood at saving electricity

Will you please write in sentences? You've been asked nicely at least six times.

If a 300 pound tractor needs a 400 pound battery, it is no longer a 300 pound tractor. It's a 700 pound tractor. But that needs a 900 pound battery, so now it's a 1600 pound tractor. Now do you see the problem?
 
I do understand ill try to use complete sentences from now on.
I'll have to settle for a small weight on the original build and will have to get a battery with a high power density. Therefore it doesn't weigh too much.
 
"and will have to get a battery with a high power density "

How exactly? And do you want power density or energy density? Do your homework.

Let me also suggest that you find out what the Tesla battery costs. Your $1000 budget, if used 100% for batteries, will buy you less energy than @phyzguy showed you needed. You need to address this. An imaginary super-cheap and super-powerful battery is not a solution.
 
Vanadium 50 said:
"and will have to get a battery with a high power density "

How exactly? And do you want power density or energy density? Do your homework.

Let me also suggest that you find out what the Tesla battery costs. Your $1000 budget, if used 100% for batteries, will buy you less energy than @phyzguy showed you needed. You need to address this. An imaginary super-cheap and super-powerful battery is not a solution.
i know that tesla batterys are expensive also i meant energy density i was mistaken
 
thank you for your previous help.
 
Just tracked down the batteries for that Ryobi lawn mower thet @Keith_McClary found.

4 batteries, each 12V, 75AH = 3600Wh total
2 hour run time, 12 hour charge time
Weight 575lbs + rider = about 740lbs total
Battery cost $172 each = USD $688 (Ouch!)

A rough estimate based on battery power and run time yields about 2 to 2.5hp maximum; probably less for 'typical' operation.

Cheers,
Tom
 
thank you that's really helpful,but if i reduced the hp would the battery last longer?
 
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