Inverter question

[QFP]

I have a 2013 voltage 3905 I would like to add a 5k inverter. I have 4 - 6volts 215 amphours each. They are set up in series/parallel. Has any one added an inverter and did you add a second transfer switch?

[retirediaffcamp]

1000 watt min for the inverter or 2000 watt should suffice. Anything more you will probably need a lot more batteries, not to mention the weight added by adding the batteries. Might I suggest a generator such as two Honda 2000 watt inverter type connected would be enough to run your ac if needed. Meantime reduce your load everywhere possible including changing your interior and exterior to led type. I use one Honda Generator which is enough for most of my needs except for a/c

[thomas201]

Try using a French press and heat your water on the stove for coffee. Forget about the TV, and you can go for 2 or 3 days without listening to the generator. Enjoy the silence in the boonies.

[QFP]

Thanks everyone for all the good advice. My rig does have a 5.5kw generator and dual refer. I think i'll lower my rating just for the tv,stereos and coffer maker,

[Veebyes]

Battery bank capacity is king. 4 x 6v is better than most but still not much. I had 6 x 6v plus a 2 kw pure sine wave inverter charger & solar in a previous 5er.

Now that was a 5er ready to go dry camping in.

You have nothing unless you have the battery capacity to power it & the understanding of how it all works.

[christopherglen]

I have a 3kw inverter charger that surges to 6kw. I run on 4/0 cables, and have no problems running both AC's off the inverter. 15 minutes later the low voltage alarm is on, and the inverter shuts down. You need to remember an AH is not an AH. The faster you pull current from a battery, the lower the capacity you have to work with. Most batteries are rated at their 24 hour rate, a 2 hour rate looses about 1/4 the capacity. Specifications for Concorde Sun Xtender AGM Deep Cycle Batteries
What are you attempting to run that requires that much power? Most rv's (other then the AC) can run quite happily off a 2kw generator. Many dry campers take only a 1kw to back up solar.

[Me_Again]

There is no free lunch with an inverter! You have to be able to recharge the batteries, and that can take hours and hours depending on the charger. The area between 50 and 85 percent is the real workhorse area once you leave shore power, as the area from 85 to 100 takes extended charge time to complete as amps accepted by the batteries tapers off. So in the attached spread sheet you have around 150 amp hours to really work with in the field, which is very little. You need an amp hour gauge and a lot more battery. I have 780 amp hours in my boat and can run about three days without charging by tightly managing usage, with refrigeration being my biggest user. The boat has a 140 amp alt and smart regulator on one of the engines just for the house bank, and the Heart West Marine 1500 inverter has a 75 amp 4 stage charger.

In the trailer I have it setup with a Honda eu1000i that powers the converter and will charge at around 40 amps. On the other side of the batteries is a Heart Freedom 10 inverter/charger that can power hair dryers and microwaves that the Honda will not. So I can dry camp and have full sat receiver and HD TV running on the inverter, and still take down the little Honda to cool and refuel before bringing it back online.

So getting the power out of the batteries to an inverter is only half the story. BTW this spread sheet is available on request via PM with an email address to send it to. It has a single cell to insert battery bank amp hours and computes the rest. Chris

[N-Trouble]

pianotuna wrote:
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.

^^THIS^^

5kW is rediculous. Get a good quality 1-1.5kW pure sine.

[pianotuna]

Two paths. Total inverter power capable of doing all major loads (one at a time if you skimp on the battery bank).

Or

Multiple small inverters tasked with running one device at a time. Unfortunately DC power losses are huge.

[wantabe351]

I to when started out on my first 5th wheel looked to power the entire rv on a mega inverter..but things just worked out differently than I had planned..most of my 5er was set up as 12v,lights,water pump,heat,Fantastic Fan for cooling,12v bedrm TV, so really what was the 110v for Livingrm TV and Sat.Box,and a few chargers for phones,laptops..The Micro,AC,Frig on 110,and water heat just draw way too many amps... So after doing reasearch I have a 5KW generator built in for running the Dual AC system to cool us off when its just too hot or micro wave, and both for lunch during mid day heat...for the TV and Sat.Box a 600w PSW inverter wired to a extra outlet by the livingrm tv for clean power and a 1500w MSW inverter wire to a outlet set into the steps going into the bedrm..using a extension cord for morning coffee maker and what might need some extra power when dry camping..now to charge the 4-6v batteries-shore power from the rv's 65amp converter, the generator powering the rv thus the converter and now the best invention- Solar Panels..which I have a 100w setup to just keep my batteries charged up when parked in storage and then the 2-250w panels for out camping at say at the race track watching nhra or nascar..everyones needs are different and then their setup will be different too.

[pianotuna]

X2 on the 1000 watt pure sine wave inverter.

[time2roll]

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?

[pianotuna]

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.

[GordonThree]

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.

[pianotuna]

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.