Battery

5 hr x 260 A = 1300 amp-hours. However, you don't want to discharge the battery all the way, so it should be sized for something like 2000 amp-hours.

Current is instantaneous; it is not consumed per hour. (That would be meaningless amps ÷ hours; instead, you are dealing with amp-hours = amps x hours.)

if the battery of 1300Ah battery is what i require, the machine needs a 260A current ,and should run for 5hours, how can i know if that the machine takes the current for entire hour or per hour or per min?

if the machine requires 260A and if i take a battery of 1300Ah, it would mean that the battery is discharging at 1300 Amps per hour so if the machine takes 260 Amps then what happens to the rest of the current.

the motor takes 260Amps so does it mean that it will take total 260 Amps as long as it is on ? so 260Amps for 5 working hours also and may be 260 Amps for 8 woking hours also? please help me solve my confusion

thank you

If you continuously deep discharge the battery you will ruin it, added to which towards the end of the discharge cycle you get appreciable volt drop on the output. A 2000Ah battery seems a good compromise. The extra 700Ah is your reservoir of reserve power to prevent damage to the battery.

Also make sure your battery selection is appropriate for the current draw. 260 amps is a very large draw and should be applied using many batteries and large cables.

Is this a homework question, because it sounds like one the way you have phrased it?

Are you really planning on playing with 1300Ah of batteries (and its associated battery charger(s)? If so I would suggest you get someone to do the installation and calculations for you as the levels of stored energy you are talking about could potentially be fatal if the batteries, protection, hydrogen gas ventilation, etc is not calculated and installed correctly.

I think it's a homework question too, but what the heck, I'm feeling generous today.

48VDC? Who uses that on machines? The only place I have seen 48VDC used in in telecom equipment and electric vehicles. If it's an electric vehicle, that makes it about 12.5kW (16HP). A golf cart maybe? A Scooter? Can't do much with that small of a motor.

But you don't have enough information. YOU need to know how long it will run. The information you have does not include that nor can you derive it from that.

If you get it, here's the basic formula:

(Total Load x Days of Storage) / (System Voltage x Efficiency after system losses)
260A x 48VDC = 12480W x 5 hours = 62.4kWh

If you wanted it to run 1 day on the batteries, that's 62,400 Wh, / (48V x 80% eff.) = 1625Ah, but if you use 12VDC batteries rated 250Ah each (assuming you find one that large), that's 7 banks of 12V batteries in series strings of 4, so 28 750Ah 12V batteries for 1 day's worth of operation. This is assuming your 260A already assumed efficiency of whatever your motor drive system was (the .8 was the storage system efficiency). If not, factor that up.

At 1.4lbs / Ah average on a gel cell, that's 2,275 lbs of batteries to run a 16HP motor for 1 day, 5 hours total before recharging. I hope that's not an electric vehicle...

1300 AH is the requirement but as it is already been said you don't want fully discharge the batteries after 5 hours. In this case, you need a design factor and aging factor. The design factor is generally 15% and the aging factor is 25%. So, you need 1,300 x 1.15 x 1.25 = 1,869 AH. You could choose the batteries of the Ampere-Hour in this range.

- MS

I have a battery with 5 hour rating and 600Ah nominal capacity. If my motor draws a current of 260A, then to how much current does the battery much discharge before a recharge?

Do your own homework. You will learn more.

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