Inverter question

QFP wrote:
I want to power as much as I can including TVs and refer. With 4 batteries i should have 400 amp.hrs. So you have 2 transfer switches?

TVs about 300 watts, Fridge maybe 350 watts so 1000 watt inverter is all you need. I have and recommend Go Power sine wave.

Multiple transfer switches is not a problem. Running the absorption fridge will drain your batteries completely every day. I recommend running on propane or is this a compressor fridge?

Hi,

Let's take the fridge as an example. A typical absorption fridge draws 325 watts on a duty cycle of 2:3. To "translate" that to amp-hours at 12 volts, taking into consideration inverter losses just divide by 10.

That means the fridge, when the element is running, will draw 32.5 amps. 2:3 means that 20 amp-hours may be used each hour the fridge is on.

To stay above 50% state of charge, run time for the fridge only would be 10 hours.

But, there are other parasitic loads that also need power. Some RV's are quite efficient, but a "rule of thumb" may be about 30 amp-hours per day.

200 - 30 = 170 left to run the fridge--or about 8.5 hours.

Unfortunately, that is not all that happens. As the battery bank discharges the voltage on the battery bank starts to drop. The inverter attempts to compensate for this by drawing more and more amps.

The end result is that for a 400 amp-hour bank, with the fridge running on 120 volts that probably 50% may come at about six hours.

You either need a LOT bigger battery bank, or a way to generate power.

One way is a generator.

Another way is drawing power from the alternator when traveling down the road.

A wonderful way is to have a solar system.

I did a careful analysis of this several years ago. I concluded that a solar system would have to be about 600 watts to power an absorption fridge and that the battery bank needed to be about 720 amp-hours (assuming the 50% rule). I had enough battery bank, but not enough solar wattage.

QFP wrote:
I want to power as much as I can including TVs and refer. With 4 batteries i should have 400 amp.hrs.

Dual 2000 watt Magnasine inverters would power both legs of a 50 amp rv (consult manual for how.) But you need more batteries, 4x 6v gc aren't enough.

Hi,

I simply plug the shore power cord into the inverter. I set the fridge to propane, and disconnect the converter.

If you want the battery bank to have a long life, then it is best to stay above 50% state of charge--so the usable amp-hours are about 200.

I know of no reliable 5000 watt pure sine wave inverter. Stay away from the Chinese ones.

I want to power as much as I can including TVs and refer. With 4 batteries i should have 400 amp.hrs. So you have 2 transfer switches?

2000 is plenty and about max with four batteries.

Yes added a transfer switch as part of the install. My 2000w inverter just powers the microwave and one added kitchen outlet.

What do you expect to run with 5000 watts?

By 5k you mean 5000 watts, peak or continuous? Get four more batteries and run 'em at 48volts. 5000 watts at 12 volts is 416 amps, you're looking at doubled or triple #0000 cables, and short ones at that. 5kw at 48v is about 100 amps or enough for a single #0000 cable to handle, even at length.

You may want to do yourself some 12 volt education, what you "would like" to do really is not feasible. I would suggest starting out with this site and do a little goggling 12 volt inverters.

Good luck on your travels.