How much wattage would be needed to charge a 12volt battery while using an inverter?

An inverter changes 12vdc to ac. If it is 35 k it may be 35000watts. Therefore it needs that many watts or more to run it efficiently. Check with a manual for information on how many watts it needs. Most average homes need 10000watts or 10kilo-watts. If you are making DC Volts you need to hook up an AC LINE INTO YOUR VACATIONER and this will give you standard a.c. for refrigerator and overhead lighting. With that 35k watts if that is so you may need a 240 VOLT AC HOOK UP.. Some trailers use AC and some DC . Mine has an inverter but I think it uses120 volt AC . Some VACATION Homes have DC possibly 4 -12volt batteries or more but those batteries are each possibly 300 AMPS at. around 14.5 volts DC. Watts =VOLTS x AMPS . 14.5 X 300 = 4350 X 4 =17400 Watts or 17.4 k watts . 120 VAC input times 15 AMPS = 1800 watts standard a.c. But with 240VAC x 25AMPS = 6000 watts. Along with those 4 batteries it would have plenty of power to run it. If the Dc was hooked to an inverter it would produce a.c. Instead of DC. Inverters are all different so check the wattage being output and input.

Some things to clarify:
Is the battery a 12volt or 24volt? I will assume a 12volt.
You should always have a fuse between the battery and the inverter. The fuse rating and wiring between the battery and your inverter depend upon the size of the load you will hook up to your inverter.
Inverters are usually NOT 100% efficient. Typically they are 80-90% efficient. If you run an inverter at rated load (your case 3000watts), you will most likely damage the inverter. If you run the 3000watt rated inverter at 500watts or less, you will have significant internal losses.
The capacity of the battery is important.
The type of battery is important (Flooded, Gel or GSM).
A 12volt battery is usually fully charged at 14 volts, but as it discharges, the voltage will drop. Batteries should not be operated at less than 11volts and most likely be damaged permanently if allowed to go below 10.5volts.
If a battery is rated at 100 amp/hours, that means it can supply 100 amps of current at 12volts for 1 hour, or 50 amps for 2 hours or 10 amps for 10 hours.
Now for the more important part. Assume your inverter is 80% efficient. 3000 x .8 = 2400. So the maximum load your inverter can safely handle is 2400watts. At 120volts you will be drawing about 20 amps of current at full load.
If you are going to draw full load, your battery must be able to supply the current to that inverter at an equivalent power rating (power out + power loss = power in). Therefore, 3000watts ÷ 12volts = 250 amps. If your load is only 1000watts (80%), load plus loss will be 1250watts, and therefore, the battery will need to supply 1250 ÷ 12volts = 104 amps. Why is this important? Because the wire between the battery and the inverter must be capable of carrying that current. And that becomes even more important, because if the wire carrying that current is undersized, it could start a fire. Also, with Direct Current, there is more of a loss than with Alternating Current. So if your battery is 20 feet from your inverter, it will incur twice the loss if it was only 10 feet away. You may have to use some very large gauge wire to satisfy the requirements.

yes, but a slightly depleted battery will take longer to reach full charge if the current is being drawn from it.... although if it's an LED light and efficient radio the current draw will be almost negligible or hardly enough to notice.

but why would you want to run mains electrical items from a battery that's plugged into the mains?
it's much more efficient to use mains electrical power for your devices until there's a power outage (this is where the inverter is really needed) or you need mains power in the middle of nowhere.

if you absolutely want to go down this route maybe an old UPS would come in handy, it will continue to output mains power in the event of a power outage.... just connect your battery in place of the old dead one (your 32Ah won't fit in the box, just use heavy cable) UPS boxes hold a 12v battery, it's a simple hack.

If you have a 12volt standard electrical system in your vehicle.
It is both positive and negative. The travel inverter converts this 12 volt DC current into 110v 60hz AC current so you can plug in your electronics that require standard household current to charge/operate.
There is a built in USB port if you device will accept this for 12 volt power. It also has the power oultet with ground for 110v 6hz power.
Link below has a good picture and description. Hope this helps!

http://www.sears.com/diehard-120-watt-ultra-slim-travel-inverter-with/p-02871520000P

the current from the 12volt supply is not sufficient try a fully charged car battery instead, your inverter needs 30 amps and above of current from 12 volt power supply

Dear, Please check following

1. Are you using correct gauge of wire for batteries (Specification mentioned in the manual)
2. You need to charge your batteries at least for 8 hours (as recommended by Mercury)
3. Please place your Inverter in a cool environment (20 to 30 C)
4. Nominal voltage of battery should be 12Volt if using 1x Battery.

Regards.

carry an extra altenator just in case for your truck

Question does not seem to match this inverters capability.

INFO:
This Power Inverter converts vehicle’s 12-volt DC power into household 115-volt AC power. AC and USB outlets power and/or recharge personal electronics.

We have owned one of these Power inverters for over a year now and have run a great deal with it, from TV to drill press PC and any thing that was small and that could run from my car. Very nice product.

SET UP: Connect wires. ensure correct polarity, push button on top. Plug in 110 volt appliance.

Hope this tip was of some use.

R/
David

Hello,

As I understand your statement, Your inverter (Powerline 200watt) has the UPS plugged into it, but it is not able to keep the UPS powered on. You didn't mention the size of the load (PC), nor the wattage rating of the UPS, or the batter bank size that supplies the inverter.

It sounds like you are trying to create an electrical system with double redundancy. If this is the case, you are going about it wrong. Most inexpensive inverters will have a Modified Sine Wave output, that the UPS will detect as a poor AC signal, and revert to backup mode, rather than pass the inverter power to the load.

200 watts isn't going to be very much for anything. 200watts / 120 volts (assuming 120vac system) is only 1.6amps or so. The charger on the UPS will likely use this much just to keep the internal battery topped off. As the PC is turned on, and the battery charger is doing its thing, there now exists an overload at the inverter. The inverter will respond by trying to increase its output by lengthening the pulses in the MSW waveform. The UPS then sees this, interprets it as bad power, and kicks into backup mode.

Since the powerline inverter is obviously a 12volt unit (cig. lighter plug), then check the battery configuration of the UPS itself. If it is 12volts as well, then you may be able to connect the UPS directly to the batteries that were powering the inverter. Note that some modification to the UPS will be needed if there external battery connections are not already present. Even then, there is no guarantee that the charger in the UPS will be able to charge the internal plus an external battery bank.

Since the battery that powers the inverter is likely larger than that of the UPS, why not run the PC directly off the inverter itself and forgo the use of the UPS altogether?

I did a similar project for another application.
I found a person with an old UPS, this one from APC, the batteries are usualy no good after two years, you can purchase them at local electronics suppliers or a Good Battery store, got it really cheap as it did not work any longer, replaced the storage cells and it works great. Just a thought, better than building the charging circuit and inverter from scratch.