Inverter prices

jrnymn7 wrote:
Is Mr. Peukert's first name Ralph?

hahahaha

a 700 cooking watts, MW will draw about 1050w, add 10% inverter loss/conversion
and your pulling 1155w from the batteries thats 90~100 amps depending on battery voltage
an engine starts in 2~5 seconds, the inverter will be running for ?? minutes
1 minute to heat water or a cup of coffee would be 20-30 times the power needed to start the engine
6 minutes to bake a potato 120-180 times the power needed to start the engine
large loads require a large battery bank,
fully charged your new two GC's might nuke your bacon or make coffee
but early in the morning after being used at night, you might do them more harm, than you think

i have over 900amp hrs of battery bank, and i still prefer to use the generator for the MW or coffee maker , i will use the inverter, if its quiet hours
but i often buy pre cooked bacon that takes only seconds to heat up
i bake potatoes at supper during generator hours
i can make a 2 egg omelet in 90 seconds, even then i might start the drive engine and let the alternator help the batteries power the inverter

Is Mr. Peukert's first name Ralph?

"I recommend 400ah minimum for a 2000w inverter."

And I recommend 400ah minimum for a 1000w inverter. :)

mcewena,

There's a reason why most rv'ers do not run 1500w appliances. I certainly do not, and I have 430Ahs. And even if I had a 2000w inverter, I would not.

This is what I have.

http://www.amazon.com/gp/product/B00GZBHFMY/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

There are a couple reviews on YouTube about this one.

It actually works VERY WELL. It powers our 900w microwave without a hitch. The wife was using a curling iron, while a 90w TV was on, and I made popcorn. Had no troubles.

The Fans are loud, and move a lot of air. This will not be a problem if its stored below.

Its standby amperage is 0.2 amps.

I assume it could run a small AC, but have yet to try. I bought the Amazon offered insurance for a one time replacement (no questions asked) if it should ever break for an additional $12.99

I tested it myself and it is a true pure sine, and keeps a true wave (and voltage) while under load. Many cheaper PS inverters have a very distorted sine wave while under heavy loads.

I have two 1/0 ga wires from each pole of the batteries feeding it. I have 150amp fuses inline on each pos pole.

You MUST have an inverter as close to (but not in same compartment) the batteries as possible.

Even on a 250 Ah 8-D starting battery that can give up a lot of power all at once I could only run our microwave for a minute before the low voltage alarm went off. Adding the output of two 245w solar panels allowed it to run for 10 minutes before the voltage under load got to 12v. The solar only offered 34 amps but it was 34 amps of usable power without resistance restrictions.

mcewena wrote:
Even for brief (15 minutes / day) usage? What's wrong with my math then?

Voltage drop. See the above responses. No harm in trying and reporting back. We love to be proven wrong!

One more thing for you to consider: RV deep cycle batteries are not designed like car starting batteries. Car batteries deliver an explosive amount of amps for a short time, whereas deep-cells are designed for a lighter discharge over time. That's one reason you need more batteries for heavy draws.

You are discharging at the one hour rate or worse. This reduces capacity by half or more. The 220ah rating (20hr rate) becomes 50ah usable very quickly. Regardless of that... voltage will sag tremendously at these discharge rates and you will be very quickly flirting with low voltage shut down.

I recommend 400ah minimum for a 2000w inverter.

Compare here with capacity drop of US2200 (similar to T105)

http://usbattery.com/wp-content/uploads/2014/06/usb_amp_hours_chart.pdf

Mr Perkuet effect raises his head
A battery that has 185 amp Hrs at the 20 hour rate aka 9 amps draw
Will not supply 90 amps for two hours
And if you manage to use 90 amps for 45 min, you will find the battery is more than 50% discharged, it might be as low as 20% SOC
it is the chemical reaction process , producing more amps that fast reduced the SG of the electrolyte