How many batteries would it take?

Question

How many of these batteries http://www.trojan-battery.com/Products/ProductSpec.aspx?Name=J185H would it take to run this electric motor http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270010898261 for four hours?

I'm trying to determine if the electric motor could fit in a pick up truck and fill the truck bed with batteries.

Answer 1

It could be done, but man what a pain...
Lets see:

Allowing for inverter and resistive losses, lets call it 1KW per shaft horsepower, possibly slightly pessimistic, but probably in the right sort of ballpark.

Now That motor rates at around 125HP, so for full power all the time we need to supply around 125KW from the battery bank to the inverter.

For 4 hours duration, means we need 500KW/h total storage in the array.


At the 5 hour rate, that battery rates at 180A/H@12V, so assume that at the 4 hour rate it will manage 150A/H@12V = 1.8KW/H energy per battery...

Now we need 500KW/H to run that motor at full power for 4 hours via a suitable inverter drive.

Therefore we would need around 278 of those batteries to meet this demand.
@55Kg each this puts the total array weight at a tad over 15 tonnes!

This arranged in 8 series strings would give you 417V DC on the bus which is bloody dangerous but would be convenient for the inverter.

At 417V, you need 125,000/417 = 300A total bus current at full load = 37A per series string which is reasonable.

Now the one thing that might make this possible is that you will not be running at full power all the time, if you allow for running at say 20% power average then your array might get down to say 4 tonnes which just might be possible.

The application where this sort of thing can work is on a boat where your battery mass is just used as ballast.

With that much battery mass you will get very poor acceleration, so you might as well go for a much smaller motor and a lighter storage array.

Frankly, you are better off with different motor technology, and very different battery tech, switched reluctance motors were the way this was going last time I looked, and one of the lithium technologies for the power pack.

Regards, Dan.

Answer 2

The answer to how many batteries depends on the speed and continous required power. I am sure that you do not want to run the motor at its maximum rated capacity for 4 hours. If you did the calculation would look something like:

Motor Power = 150Hp X 750 Watts/Hp = 112500Watts
Motor energy for 4 hours
Energy = 112500 Watts X 4Hours X 3600 Seconds/Hour = 1.6X10^9 joules

Each battery is capable of 75Amps X 12Volts = 900 Watts for 110 minutes which gives a total energy per battery of
900Watts X 110Minutes X 60Sec/Min = 5.94X10^6 joules

Dividing the total energy required by the energy per battery would give you a number like 272 batteries. Not very practical.

Most electric cars cruise at much less than the rated capacity of the motor used. They need the extra power for acceleration. And most electric cars will not run for 4 hours at 55mph.

Answer 3

What you need is about 16 to 20, 6 volt, deep cycle, golf cart batteries in series and a forklift motor. The motor you refered to is an ac motor, you need dc. Finding a controller is the hard part, but they are available. Find an electric car club in your area if you can. The batteries will weigh about 60 pounds each. You'll need a custom made adapter plate to attach the motor to the transmission. You definitely want to use the clutch. You can make a charger using a big variac and some large diodes. You'll have a top speed of about 65 mph. Your range will be about 20 to 100 miles, depending on how you drive. Don't expect to go up hills. It's sort of like driving with only a 2 gallon gas tank, but with a pump at home. The big problem is the batteries will only last maybe 3000 to 5000 miles. Get your batteries from a battery recycler. They collect lots of good batteries. You need deep cycle batteries, because they have thicker plates. You're really using them and thin plates get hot and warp. Connect them together with large welding cables. Under full power you will be using around 50,000 watts, which is a huge amount. One horsepower = 746 watts. Don't expect to get a 100+ hp dc motor. If you need more advice write me. I have access to batteries and other things.

Answer 4

a sh#@#$%pot full that's a 440 volt 3 phase 100+ motor the inverter would be as big as a pickup truck and a city bus full of batteries to get you to the 7-11 down the street

Answer 5

The motor in question is a 3-phase motor, requiring 3-phase alternating current. It cannot run on batteries at all.

Answer 6

I think the problem here is getting a three phase inverter for a reasonable price. Your battery is 12v DC; you need to get 220v ac 3phase to get the motor spinning. It says the motor is 125 hp. You'll need an inverter that van pump out 2X that running load of 125hp to get it moving. 250hp equals 163.5kw.
Again the problem will be finding an inverter

Answer 7

Pay some one to do it for you if you don't have experience in eletrical engineering.