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

If using an inverted for small electric use, what would be the solar wattage panel needed, to maintain a good charge on the 12volt battery?

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• John Gannon Nov 09, 2018

What every you take out of the battery you need to put back in (plus the losses), the amount of watts you need is proportional to the AC load the equation I use is array size in watts X peak sun hours divided by 2 or .5 the .5 is the losses in the system also your inverter should be matched to the batteries as a rule you should not draw anymore than 100 amps from the battery .

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### John Gannon

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What every you take out of the battery you need to put back in (plus the losses), the amount of watts you need is proportional to the AC load the equation I use is array size in watts X peak sun hours divided by 2 or .5 the .5 is the losses in the system also your inverter should be matched to the batteries as a rule you should not draw anymore than 100 amps from the battery .

Posted on Nov 09, 2018

### Ibe Chukwudi

the solar panel is just to charge your inverter,if it is charging and the inverter is on it will drain the current the solar panel is supplying to the batteries,this makes it look like it is not charging ,so i advice you to switch off you inverter when charging it,get another set of batteries connected to your solar panel then charge both, let them be separated so that the new one is not in use so that when solar is out you can switch to the other set of batteries

Posted on Feb 25, 2010

### Ibe Chukwudi

it is possible the cont actor or relay that do the switching is bad

Posted on Feb 27, 2010

### frank thomas wilson

carry an extra altenator just in case for your truck

Posted on Mar 12, 2010

### Donald DCruz

This a possible failure of the voltage detection circuit in the inverter main board and requires the fault be identified by checking the voltage/current feed/limiter to the battery.
Once when the battery voltage has reached the threshold set up the charging should stop and then the circuit will analyse the voltage on the board to trigger the charging to be put ON.
This can be a failure of the detection circuit and if not checked can damage the battery.

Posted on Jun 20, 2011

### 1earthmother

I'm sorry that I can't help you, but if you're in a hurry, you can visit the Magnum website at: http://www.magnumenergy.com/Service/Servicefront.htm and try to find your model's online manual and search troubleshooting advice or you can email customer service at
[email protected] and they should at least be able to lead you in the right direction.

A few questions: Does this problem remain even when there is at least a 10+ watt load on your system? is your Magnum in a hot environment? Does your inverter feel extraordinaryily hot? Have your batteries outlived their lives? Have you cleaned all the connections? Even if they 'look' like they don't need it?

All the best to you.

Posted on Sep 11, 2011

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## Related Questions:

### Can I operate a light on a 12v battery while it is being charged with a guest 2606A

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.

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### Do I have a negative battery system or positive battery system?

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

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### Fault Light/ inverter failure

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

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### Microwave wont run with a 1500 watt inverter why

Depending on the model of the microwave it could draw more wattage than what is put out by the inverter. Don't forget there is a inital spike when your unit first starts and that although an inverter might be listed at 1500 wat that is the maximum and will depend on how much power the inverter is getting in, so if the engine is not putting out enough power the inverter will not put out a full 1500.

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### My mercury radiant 1000 inverter dose not give backup time. although my battery is new.and also tell me the salutation of increase the charging.give answer urgent pleas.

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.

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### How do i tell when the inverter is charged?

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

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### I have an inverter, then a UPS, as the inverter does not always keep the PC on. The inverter does not power the UPS so it cuts out after a few mins, I then have to take the UPS out of the system until the...

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?

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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.

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