Ok, I want a battery for when we go off grid camping. I know I need a deep cycle but the AH and stuff I don't understand.
I will be hooking up a power inverter to it(with alligator clamps) to charge laptop, phones, speakers small stuff like that. I also have a 35 watt portable air conditioner I will be having on all night.
Will be used 2 or 3 nights at a time.
What will last the whole time?
Willing to spend up to 300.
You need to understand some of the math, at least, in order to be able to figure any of this out.
To begin with, let us define
“all night” as eight hours. So, to run 35-watt air conditioner for eight hours, you need a total of {35 8 ×} 280 watt-hours of energy. To do that for three nights, you need {280 3 ×} 840 watt-hours.
Now batteries are rated in ampere-hours, not watt-hours. You need to multiply the ampere-hour rating by the voltage of the battery, to get watt-hours.
Assuming twelve-volt batteries, you need {840 12 Ă·} 70 amp-hours worth of batteries to equal that 840 watt-hours. A quick Google search got me
this statement showing up prominently in my results:
A standard small car battery is about 45 amp/hours. That means that it will supply over two amps for 20 hours. A battery should not be discharged at a higher current draw, or asked to deliver more amps than its amp/hour rating divided by 10 in order to get maximum capacity out of it.
So, the equivalent of two standard car batteries ought to do it, depending on how great the losses are in the inverter. I don't know what to assume about that, but perhaps you should with the equivalent of three or four such batteries. And, of course, you'll want to go with deep-cycle batteries, rather than standard car batteries, and I think these are likely to be of lower capacity.
