Thanks for the reply. I guess what I'm trying to figure out is how do you calculate how long a stand alone battery lasts? My stand alone says 1125 cranking amps (don't know if that's important) and it's 75aH. At 100% full load, my amps require 2800w.
I like the idea of adding an additional stand alone (identical), but I'm starting to see way too much extra weight in my bed. I'd really like to calculate how long a single larger battery would last (replacing the stock), running everything (full stereo, amps, Ranger, ect).
Right now, the cheapest thing to do is just add the isolator, keeping the stock battery in place and using the isolator to send any additional charging to the Optima to at least help with the stereo load.
Also, does anyone know about the AGM audio batteries? My Optima is a blue top and I understand it to be rated for full discharge, then recharge and it'll still be fine? Does the AGM audio battery work the same way? Is it okay to completely discharge those?
Sorry for all the questions.....I've never fully understand power demands and how to calculate them in DC systems...
Well, this is going to get real convoluted, real quick! First, if I understand it correctly, your amplifiers do not draw a constant 1400W (1400W/12V=116.7 Amps). I learned that on here about a year or so ago - not sure why they don't, I think it had something to with RMS(???) anyway, it will be less. Hope a stereo guru jumps in here. Step 1 - find out how many total amps your accessories really draw (may need to call the vendors). Step 2 - decide on how many hours you want your stuff to play (without the isolator - we'll add that in later....) Step 3 - do a google search on "Battery Load Calculator" Stop 4 - enter the data from step 1 and 2.
If, in fact, your amps draw a constant 2400W (which I don't think they do) that would be a 233 amp draw. Using the calculator, to run your stuff 1 hour would require a battery with a battery of 768 aH rating for 20 hrs. If you amplifiers draw 300W total (probably a little closer to reality) that figure changes to 84 aH and since you would be feeding 42 amps back into your aux battery via the stator/isolator, you would, of course get some more time... but you are still going run out of juice eventually.
OK, all that is a big ole SWAG (Scientific Wild A$$ Guess) on my part - I sure wouldn't take any of it to the bank - my stereo skills rank right up there with my brain surgery skills! What I would do is call in a stereo expert to help you size your battery - maybe Crutchfield would help you out(?)
As far as your battery type question (I am a bit better at this!) the battery chemistry (Gel, AGM, or Flooded) really doesn't have much to do how much DOD (Depth of Discharge) a battery can handle or how many time it can survive being totally discharged. That is more a question of the batteries architecture; an SLI (Starting, Lighting, Ignition) battery, like the one that came stock in your Ranger, is the most common type. It is designed to give you an initial, high burst of power to start you machine but it doesn't like a high DOD and can only be completely drained a few times before it's toast. At the other end of the spectrum are Deep Cycle batteries. They have thicker lead plates and are designed for high DOD and can be drained many times (your Blue Top is one). Between the SLIs and Deep Cycles are Hybrid batteries that give you the benefits of both (although not to the extreme of either). The Odyssey batteries that most of us use are a such a hybrid - ideal for use in most SXSs (except yours!)
All Odyssey and Optima batteries are AGM (Absorbed Glass Mat). Nice because they don't require any maintenance other than an occasional charge if you let them get low. Gel batteries are about gone off the market being replaced by AGMs. Flooded batteries are the cheap ones - good but require venting and additional fluid (distilled water) from time to time. Your Kinetik HC2400-BLU is an (AGM) SLI, I think. Lots of power but won't like being discharged. Expensive as heck also!