Battery backup run time

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Old 02-06-20, 07:46 PM
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Battery backup run time

So if I have something that pulls 2.2 watts at 120 volts. How long roughly can I run it off of a 1000 cca battery with a power inverter
 
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Old 02-06-20, 08:13 PM
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2.2 watts is a pretty low for a battery that size. First you need to consider the efficiency of your inverter as it might waste as much power as you're using if you don't choose an appropriately sized one. With such a light load the efficiency of the inverter can have a huge impact on how long you can power the device.

The next thing you ned to look at is your battery. What chemistry/type is it? A wet lead car starting battery can be drained differently than a deep cycle lead battery, which is different than a sealed or jell cell battery. Then there are modern lithium options like LiFe and LiPo. Each type of battery can be discharged to a different level without affecting the life of the battery.
 
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Old 02-06-20, 08:41 PM
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CCA is instantaneous power - cold cranking amps.
The spec that tells you how long it will run is amp hours- Ah.
 
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Old 02-06-20, 08:52 PM
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1000 cca is probably about 60ah.group 27? 31"

Draw is .18 amps @ 12 volts. Plus loss from inverter lets round to .25 amps.

thats 240 hours but @ 50% drain thats 120hrs.

About 5 days...

but purkerts law comes into play.. 3 days or so?

and thats if batt fully charged and not sulfated..



 
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Old 02-07-20, 04:38 AM
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Long story short it's just running a natural gas fireplace. Would I want a small inverter for this? I have no experience with battery inverters
 
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Old 02-07-20, 05:27 AM
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Short answer is yes. A small inverter will more than likely work, however.........

You need to look at the specs & see what the watt draw is because that's usually how you buy inverts. They come 100 watts, 200 watts, etc on up into the 1000s.
If your fireplace draws 100 watts, you'll need to buy one at least that size.... normally a little bigger with some start up surge room etc.
I easily run a TV & laptop off a 300 watt inverter.

Keep in mind that the bigger inverter you get, the more amps its gonna take to run the inverter.
 
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Old 02-07-20, 11:27 AM
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You need the inverter because the battery is 12 volts DC and the draw you described is 120 volts AC. The inverter will convert the AC to DC and output 12 volts. You can't just connect a 120 volt AC device to a 12 volt DC power source.

- Peter
 
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Old 02-07-20, 01:25 PM
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If it's just running the fan I would consider converting it to DC. Either replace the blower entirely or swap in a DC motor. That way you don't have the expense or conversion loss of an inverter.
 
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Old 02-07-20, 05:50 PM
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As mentioned..... do you have a fan.
If no fan..... you may be able to run the fireplace directly of DC power.

A make and model of the fireplace would be very helpful.
 
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Old 02-07-20, 07:10 PM
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It's a desa. The company doesn't exist anymore. You can light it with a remote while it's plugged into the wall. Or you can light it manually, the manual part quit working and I can't figure it out. That's why I was wanting to run it off of a battery when we lose power
 
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Old 02-07-20, 07:29 PM
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What happens, or doesn't, when you try to operate it in manual mode? It's probably something easy to fix if it works in electronic mode.
 
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Old 02-07-20, 07:46 PM
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Whats the model #. Those units do not need electric to run except if its got a fan. And you dont need the fan per se


https://www.desatech.com/fireplaces.htm
 
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Old 02-08-20, 01:03 PM
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Old 02-08-20, 09:46 PM
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Thats electronic ignition looks like.. Needs 24 volts to light. do you have pizo igniter?

Ill look up more info.

hey why not just call a repir place to come.. They will get it working properly.
 
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Old 02-08-20, 09:47 PM
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