Inverter Tips?

[SoulFire]

My friends and I are looking for an inverter to put in our 1979 Crown Super Coach. In looking at some of them I saw that they have a warning alarm and auto shut-off when the batteries get down to %50 or so...we want to be able to run our batteries down farther than that because we will be using them to play concerts from the bus. Has anyone heard of any inverters without this low battery auto shut-off?

Any suggestions on quality inverters are much appreciated. We're thinking we'll need a 2500-3000 watt unit.

Thanks!

[the_experience03]

I haven't heard of any that shut down at a 50% state of charge (12.2 volts). I know mine will sound the alarm at about 10.8 volts, but this is WAY too discharged to start the bus and is very damaging to the batteries. Speaking of which...you do NOT want to be running your batteries down more than 50%. You will dramatically shorten the life of the batteries. Seriously. It will be cheaper to buy twice as many batteries and only run them down 50% than to run a smaller set down 100% every time and have to replace them so much more often.

Do you have a link to these new inverters?

*edit* One other thought. Just how long are you planning on doing these concerts? At a 3000 watt draw for two hours and going down to a 100% state of discharge will still require a 500 amp hour battery bank at a minimum. That's four golf cart batteries to barely get by for two hours. I think you might want to do some more figuring and planning.

[elkoskoolie]

I put a Cobra 2500Watt in my Gillig for working at Burningman. Typical modified sine wave. It worked well, BUT
1. My clock did not keep proper time. If you need to get up or keep a schedule, get a battery operated clock.
2. The microwave worked, but the light was a funny color, and it didn't sound happy.
everything else operated fine.

I'm sure both of these were symptoms of the "modified sine wave". If you have devices any more demanding then mine, might want to look for a true sine wave. My inverter will take a remote switch- since the inverter is in the basement, this is a handy feature.

[SoulFire]

Thanks for the tips guys!

So our bus already has two deep cycle batteries. One (I'm assuming) for starting and on for auxilary lights, fans, etc. We are planning on tapping into the auxilary battery as well as adding one or two more deep cycle batteries. I've heard that they're the best bet because of their ability to put energy out for extended periods of time...but I've also heard advantages about golf cart batteries because of their ability to be run much lower than conventionals. We will be running two guitar amps, a bass amp and a P.A. for 2-3 hours? My guitar amp is 60 watts x2= 120W Plus 120W bass amp= 240W plus 150W PA = 390W. I don't know if this is the correct way to measure the electrical draw of our equipment. It seems to me like this setup would use more than 390 watts.

?

[lapeer20m]

the above poster is absolutely correct, discharging batteries below 50% is very very bad.

my favorite batteries for feeding a large inverter and/or for engine starting are "8D" batteries. They are physically huge, cost about $150, and are used on millions of semi trucks. The batteries are built to start large diesel engines, and also run electrical loads for hours while the trucks are parked and not running. In my personal experience, i believe a single 8D to be superior to a pair of 6v golf cart batteries. An 8D weighs about 130 pounds and is about the size of 3 regular truck batteries.

400 watts is not much current draw.

I have used a modified sin wave inverter to run all kinds of stuff from rooftop a/c, microwave, freezer, electric griddle, toaster oven, lap top, tv, entertainment center, chargers, etc etc.....I've found very few things that are unhappy with modified sin wave.

Workaholic - 1400 CCA (8D-MHD)
SPECIFICATIONS
Weight: 131.70 pounds
Length: 20.75 inches
Width: 11 inches
Height: 9.63 inches
Cranking Amps: 1750
Cold Cranking Amps: 1400
Voltage: 12
Termination: A
Time at 25amp draw: 8hrs

[the_experience03]

First things first would be to take your time and truly calculate your electrical demands. To find out the wattage you will need you will need to look on the back of the amps, for example. Near where the plug goes in you should see a tag that will say something like 110 Volts, 1.2 amps, 60 hz. Just because the output power of the amplifier is 60 watts doesn't mean that is what it will draw. It will likely draw more than that. Look for the tags on everything you are going to run. Watts=amps times volts. So...say the amp draws 1 amp and runs at 110 volts...you would have a draw of 110 watts. Easy enough, right? Get that far and we can help you some more.