battery shaped like a football.....

First off,
The AGM 'Jelly Roll' or 'Six Pack' batteries have a 50% failure rate out of the box...
Meaning 50% won't live through a 12 month warranty period.

It's do to their design, paper thin plates sandwich a Gelled electrolyte impregnated fiberglass mat, then they are rolled to fit in the 'Tubes' (Cell Housings).
During manufacture, more are discarded than produced because the plates are so fragile.

The ones that pass initial inspection die over time since the electrolyte produces gasses anytime the battery is charging or discharging,
And those gas bubbles can't escape through the Gel.
They are held on the plates, creating a 'Dead Spot' the electrolyte can no longer come into contact with.

These bubbles add up and pretty soon, you have one VERY LARGE resistor built into the battery.

Secondly,
A 1,200 Watt inverter is WAY too big for a single battery!
Especially one with as small of reserve as that 'AGM' you are using.

A 1,200 Watt inverter (at 110 Volts) requires 10.90 AMPS (at 12 volts) from the battery to produce even NOMINAL voltage (open circuit, nothing plugged in!).

If you load the inverter with anything, and I mean ANYTHING, you are looking at 200 to 400 Amps before the circuit protection opens and saves the inverter!
(It's called 'Surge' operation)

Inverters are HUGE drains on the batteries they are connected to!
Surge loads on inverters can EASILY exceed the load from the starter motor when the engine is hard to start!

I am just AMAZED that battery lasted as long as it did!

Put in a new battery, have your charing system 'Analyzed' at one (or more) of the 'Discount' stores.
Since the service is FREE to you, and the operator might not know what he's doing, get a consensus from two or three places before you change alternator, regulator or whatever.
..........................

If you are going to continue using the inverter,
Make sure of THREE THINGS...

1. You use a FLOODED lead/acid battery so the bubbles from deep discharge and quick charging can escape.

'Heavy Equipment' batteries have more material in the plates, have captured plates top and bottom, and usually have a protective layer of material between plates to keep a loose plate from shorting out the cell when you beat them around.
Check out 'Tractor' batteries, or batteries intended for Heavy Equipment.

Heavy equipment batteries also have 'Slosh' or 'Roll-Over' protected caps so they don't leak on sever angles or when bounced around...

2. Use a DEEP CYCLE battery for your inverter since inverter loads can exceed 'Discharged' battery voltage before you recharge.

3. Use TWO OR MORE, FULL SIZE BATTERIES when you are going to use Winches, Inverters, or anything else that will draw the batteries below 12.2 Volts during usage.

I would also recommend you use LARGE CABLE to feed the inverter, smaller cables to the inverter will cause problems with the inverter when you starve it for amperage.

 

dude my brain actually hurts now ,,,,,,,thats alot of info to process.thanks ,

don't thinkI will replace the inverter ,it was mostly for a trail grinder . I now have OBA and can use air . but that inverter would power my skill -saw and my big 12 amp millwalkee grinder but ,,,,I would have to turn it down low to start.It was never switched on till it was needed.but did work every time at the expense of the battery .

 

Most 12 volt alternators are capable of running 110 volt brush motor appliances without an inverter...
Just takes a bit of creative wiring inside and outside the alternator.

Personally, I prefer an alternator that has CONTROLLED ground, doesn't ground through the case, but actually has a 'NEGATIVE' terminal...
That way you can use STRAIGHT WELDING POLARITY when doing trail repairs,
Instead of using Reverse Welding Polarity to keep the alternator it's self alive,
And you get MUCH deeper penetration.

Welding 'Straight Polarity' is work piece POSITIVE, electrode NEGATIVE, and that can't happen with a negative grounded vehicle since the alternator is grounded to the vehicle. You are basically heaping bird droppings on the weld, instead of getting good penetration.

You can work on SOMEONE ELSE'S vehicle,
Or you can take the part off and weld STRAIGHT POLARITY, but you can't do your OWN vehicle, and that is the one I'm worried about most!

Anyway, if you want to wire up any modern alternator to output AC voltage, all you need to do is attach to the STATOR TAPS, and run those lines out of the case to a 'Plug In'...
Use one as 'Ground', One will be 'Hot' (no 'Positive' in AC wiring) and one will be Neutral.

Then take control of the rotor (Field) of the alternator so you can add or subtract voltage to get your desired output...
(110 or 220 Volts).
If you are a little more tricky, you can produce in 220 volt 3 Phase, but I can't see a practical use for that even if you *CAN* do it, you are just showing off!)

Using a Leece-Neville Alternator makes things SO MUCH MORE SIMPLE!
Leece-Neville (Lester #7611) has AC taps coming out the back of the case so you don't have to monkey with wiring inside the case,
And they have the most easily removed/Overridden voltage regulator...
They also are VERY EASY to attach an extra Rectifier Bridge to the back of the alternator so you can blast away at 160 Amps all day long without overheating the unit.

Weld with TIG/MIG (gun)/Stick In AC or DC, Straight or Reverse polarity on YOUR vehicle,
And with the amperage that unit puts out, you can run a plasma cutter with no problems if you have 'Dry' gas or an On Board Air compressor.
------------------------------------

On the flip side,
If you have TWO batteries, and some small diameter rods,
You can use good size jumper cables to weld right off the 24 volts of the batteries.
Granted, doing this will discharge the batteries pretty quickly, but a 'Burning Rod' is MUCH faster at getting 'Carnage' cut away than using a hack saw!
AND!
You can weld up your own 'Junk' to get back in!

I don't know how many jack handles we've cut up to fix steering linkages, ect.!
Just a couple of batteries and you are off to the races!
Plus your winch will treat you MUCH better with two batteries!

 

So after looking at the picture of your battery have you ever had to jump start it. I have a red top Optima battery as well that was fine but left my head light on one morning and had to get jumped off. After that I have a battery that looked the same. After some research found out that Optima batteries like a slow charge not jump starting.

 

my voltage reg had taken a dump and was pumping 16+into it.and yes Optimas like a slow charge, they even make a special charger for them.