power invertor
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Senior User
Joined: Feb 2003
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power invertor
Does anyone have any experience with an invertor? I know it will drain a battery fairly quickly, but could someone give me a ballpark figure of how long I could run a 400W continous power invertor on a typical car battery?
Senior User
Joined: Mar 2003
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We use these at work. http://www.chargeguard.com/what_is_charge.html It will turn off invertor while the truck will still start. It is hard to say how long your invertor will last, it depends on efficiency, load(watts used) and reserve time of battery.
Chris
Chris
Elder User
Joined: Sep 2004
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To calculate this accurately, you need to know the actual load on the inverter, not the maximum capability of the inverter.
If you were running it flat out (max load on the 120V side).
400W / 12 volts = 33 amps
Assume an 80% efficient inverter => actual draw 41 amps
A group 24 deep-cycle battery has a capacity of about 70 amp hours.
70/41 = 1.7 hours
Theoretically, the inverter could be run for about 1 hour 45 minutes. There are two factors which would likely reduce this:
The battery voltage will fall off towards the end of the discharge cycle, causing the current to go up and the duration to go down.
41 amps is a relatively high sustained battery discharge current. The battery will probably not deliver its full rated storage capacity.
So I estimate 1 hour and 20 minutes at 400 watts.
If you were running it flat out (max load on the 120V side).
400W / 12 volts = 33 amps
Assume an 80% efficient inverter => actual draw 41 amps
A group 24 deep-cycle battery has a capacity of about 70 amp hours.
70/41 = 1.7 hours
Theoretically, the inverter could be run for about 1 hour 45 minutes. There are two factors which would likely reduce this:
The battery voltage will fall off towards the end of the discharge cycle, causing the current to go up and the duration to go down.
41 amps is a relatively high sustained battery discharge current. The battery will probably not deliver its full rated storage capacity.
So I estimate 1 hour and 20 minutes at 400 watts.
Mountain Pass
Joined: Nov 2004
Posts: 192
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From: Marietta GA
A 400w Inverter will draw 33 amps from the battery First you have to check the RC minutes of the Battery, the RC is rated at 25 amps @80 degrees. If you have a 160min RC battery the inverter will be able to run for 120 min (max) before discharging the battery. Some inverters have a automatic undervoltage shut down to keep from frying the appliance that is connected to them. So depending on the "Health" and state of charge of your battery that 120 min could be significantly shorter
