I am presently running batteries and an inverter that is 400 watts. My question is this: Does this inverter draw 400 watts regardless is whether I'm only running a few watts in lights?
If I switch to a 75watt inverter when I'm only running a laptop or a light (got only one light in my shack anyhow), will my batteries last longer until I need to fire up the generater and recharge them?
Your 400w inverter is limited to 400w output. The power loss from the inverter isn't enough to worry about, like 1/4 amp from your battery. That 1/4 amp will drain even with no load, so turn the inverter off when you're leaving for the day to keep your battery at max.
Thanks for the reply. Let me try and clarify a bit though as I may have been a bit confusing in my first question.
I always turn things off when I'm not there including shutting the inverter off and or unplugging it.
My question is more like: is the actual drain on my battery 400Watts when actually using it? Or is the drain only what the wattage of the computer/appliances demand?
IE if I am only using a 24watt bulb through my inverter does my 400watt inverter drain more power from my battery than the 24watt bulb requires?
I have a lower power inverter (in storage) and if it wold give me more hours before recharging (no panels yet), I'd use it instead.
Your battery usage is equal to your demand plus the small loss from the inverter. If you turn 3 light bulbs on, your battery is being used at three times the rate as if you turned on one light. Even with your 400w inverter, a 50 watt device is only sucking 50 watts equivalent out of the battery. The only advantage you'd see in using a smaller inverter is the inverter consumption may go down, but probably not enough that you'd notice a difference in battery duration.
For the fun of it I tested my 300 watt inverter.
Idle current = ? did not check.
150 watt light plug into inverter = 14 amp @ 13v from battery = 182 watts dc
The inverter is using, 32 watts or 2.46 amp @ 13v to produce 150 watts @ 120v ac.
Efficiency = 82%
Letís assume we are now using a 23w fluorescent light.
23w ac @ 82% = 28 watts @ 13v.
28 watts = 2.15 amps @ 13v
Youíre wasting 3 watts or .23 amps.
For minimum battery drain, I would turn off the inverter when not in use.
I would also use a 12v led light (hard to read by) or a 12v car/marine cabin light. I think they use about 2.5 amps. and I would run everything directly off the battery, if possible.
Another problem you may have is under charging or over charging your battery. Wasting gasoline on a battery that is fully charged.
Where is the best place to buy a complete package(inverter, batteries, panels)?
Thanks for the inverter answers. That answered my question perfectly.
Susitna energy systems in Anchorage is a full service solar/alternative energy store. They seem to really know their stuff. rices don't seem to bad for what they are but I haven't done any comparison shopping yet. There is another place in anchorage but I haven't checked them out yet.
I did look online but shiping cancels out any savings as far as I can see.