Microwave power question

what i did was bought a AGM deep cycle battery group 27 its a sealed battery (regular batteries let off toxic fumes not suted to be inside)
ran 900 watt inverter to the 600 watt microwave.used a small inverter that pluges into a lighter (200 watt) and ran a 1.5amp battery charger off it to charge the deep cycle.the problems is that after about 10 min of use it will take about 8hrs to charge the battery back up and the inverter thinks that the battery is low when in use so the low battery buzzer gose off the hole time you are useing the microwave will drive you insane cb shop can kill the buzzer for you though and the price of the battery is about $200 and if the battery is not fully charged the microwave will cut out on you but will restart if you have a microwave with a dial its crude but it dose work

 

Bigger is better group 27 has about 90 amp hour reserve but you can't use a standerd deep cycle or any regular battery toxic fumes it must be a AGM sealed lead aced some gel cell are sealed thay don't vent unless its ready to blow up

 

I think the microwave is DESGINED to run on 12V......so a single 12V batt (will read about 13.5 Volts when fulley charged) is all you should need....I think you were possible running the 2 ATV batts is parallel to increase capacity (volts stays the same, but it would act like one bigger battery), but keep the voltage at 12....in series the voltage would have been 24....higher than most any non-speciality plug-in car/truck use item. To be honest I have never heard of any 24 Volt DC truck/car items in the US.......
The size of the battery you buy/need depends on how long you plan on running the micro....I suspect the size should be fine....but remember, draining a battery below about 70% capacity will greatly shorten its life....I suspect that is what happened to the ATV battery....likely a starting battery...able to provide lots of power in a short burst....the deep cycle should be better able to withstand a micro running for a few minutes at a time than a starting battery...heck they are usually used to run a small electric motor or other electric items (live-well, radio's, etc) on a bass boat/RV, etc.