You did not mention the size of battery your wanting to buy. Any deep cycle battery you should never allow the battery to drop below 50 percent of its capacity. So knowing this if you buy a 100ah battery your only going to get a few hours of use.
What?! A deep cycle battery is made to "deep cycle" ie full charge to near full discharge without significant damage unlike a lead acid. Basically a deep cycle is usually AGM or absorbant glass mat or specially made lead acid and does not have the typical plates that get coated and are unable to transfer electrons like a normal lead acid.
In the past deep cycles were lead acid but with battery advancements most now are made AGM but you can still readily find lead acid deep cycles either flooded or the more popular nowadays VRLA. Since Douglas (exide) shut down companies like Banner are taking batteries into the 21rst century. With all the econuts and global warming talk our world is changing from a fossil fuel to a energy storage device world quickly. Look at the auto industry for inspiration.
True that total discharge is bad for any battery ( except lithium which is bs ) deep cycle batteries are made to handle the stress a lot better and deep cycles are designed to discharge to more than 3/4 of its total capacity. As long as the battery is charged fully before it is stored for long periods you should have atleast a year or two of great battery power as long as you have a battery with enough amp hours to run properly.
I use a 900 CCA 90Ah 160 RC BMW AGM battery for hours and hours when running my gold cube but it's not a high amperage pump. Don't be fooled howver this battery is a power monster and it does not all come down to amp hours. You have to look at reserve capacity and CCAs as well. There is so many formulas available online to help calculate just how much battery you need it's enough to make your head hurt. My advice crappy as it is is to get the most powerful most heavy most pricey ungodly battery you can afford as running out of juice in the field is as bad as running out of gas. Dead in the water literally.
I say BS that lithium a need total discharges as part of its normal discharge/recharge schedule as I have seen a few brand new I3 rEX vehicles Stone dead and unrecoverable after battery is smoked dead. Also try discharging an iPhone totally. Your battery is never the same and I don't care what Apple says- it's a ploy to ale you buy a new device just like when a new iOS comes out suddenly your old device slows down... Hummmm
Whatever you decide be ready to lug that thing around as my AGM weighs like 25lbs and is not easy to carry. Also as AZviper said it comes down to cost and weight. I get batteries free but my 950 will run you over 300 bucks!
I personally wouldn't invest too much on a battery right now as Lithium is smaller/lighter/more powerful and is really just beginning to break into the auto industry in a big way. The prices of lithium will go way down once Samsung keeps cranking them out by the thousands. Wish Ida bought stock in lithium manufacturers a few years ago...
It's the new gold rush
