Small floor electric heater

[azflycaster]

Originally Posted by seeflash

Does everyone run their electric or oil filled heaters off of generator power? All night? I've been thinking about a small Vornado myself. However I don't have a generator...just solar power.

Could I run this from a separate 125 amp/hr battery, on low (400 watt) with a portable 800 watt inverter? How long would my battery last do you think?

400 watts / 120 volts = 3.3 amps
Plus you have the inverter that uses power, so let's say 5 amps.
The battery should not be drained more them 50%, so you have 62.5 usable amp hours of battery.
62.5 amp hours / 5 amp draw = 12.5 hours

These are rough numbers and are based on a fully charged battery when you start.

[tpi]

Originally Posted by azflycaster

400 watts / 120 volts = 3.3 amps
Plus you have the inverter that uses power, so let's say 5 amps.
The battery should not be drained more them 50%, so you have 62.5 usable amp hours of battery.
62.5 amp hours / 5 amp draw = 12.5 hours

These are rough numbers and are based on a fully charged battery when you start.

You forgot to make the 120 to 12 volt conversion on the amps. If it draws 3.3 amps at 120 volts, the inverter will draw at least 33 amps at 12 volts. With conversion inefficiency, it will be closer to 40 amps at 12 volts.

[doorgunner]

Anne;

some time ago I did a thread-- Heaters, heaters, heaters. You will find detailed info of different heaters. I would link it but I don't know how.
The oil heaters sound like the way to go for you, totally safe to leave on all night whilst sleeping, and there are models with built in timers. So if you are away in the day you could have a nice warm place to get home to.

[empresley]

Originally Posted by doorgunner

Anne;

some time ago I did a thread-- Heaters, heaters, heaters.

Here you go...

http://www.airforums.com/forums/f427...ers-29283.html

[seeflash]

I just read the full thread the other day and that's what prompted me to ask the question. So, what is correct? Both sound logical.

My flat panel TV runs at 400 watts, plugged it into the inverter and ran it for 2.5 hr. movie with only .1 volt drop as I still had 12.7 volts in the morning.

More info. is welcome.

[seeflash]

Found this searching the web: thanks to all for the help.

One of the biggest mistakes made by those just starting out is not understanding the relationship between amps and amp-hour requirements of 120 volt AC items versus the effects on their DC low voltage batteries. For example, say you have a 24 volt nominal system powering a load of 3 amps, 120VAC, which has a duty cycle of 4 hours per day. You would have a 12 amp hour load (3A X 4 hrs=12 ah). However, in order to determine the true drain on your batteries you have to divide your nominal battery voltage (24v) into the voltage of the load (120v), which is 5, and then multiply this times your amp hours (12 ah). So in this case the calculation would be 60 amp hours drained from your batteries - not the 12 ah. The easiest way to quickly determine the total battery amp hours required is to first determine total watt-hours required by all loads, and then divide by the nominal DC system voltage. This resulting number will indicate the amount of amp hours needed to operate all loads for a given period. However, additional amp hour capacity would typically be added for more "reserve" capacity or to prevent complete discharge. Using the above example, 3 amps x 120 VAC x 4 hours = 1440 watt-hours divided by 24 VDC battery environment equals 60 amp-hours; the same answer as before, but another way to get it.

[adonh]

Originally Posted by 2dabeach

We now use a Vornado VH-2 heater

I wonder how this smaller version would work

Vornado

Don

[teagues]

Originally Posted by adonh

I wonder how this smaller version would work

Vornado

Don

That one doesn't appear to have a thermostat. Or at least not one that you can set to a specific temp.

[tslanier]

I just bought the Vornado DVTH Digital which can be set for 750 or 1500 watts. I used this weekend. It works great. It does have a thermastat which you can set and also gives you the current room temp.