One would be a fool to buy batteries.
THAT is the correct/ logical/ realistic/ truthful answer.
And the only one.
We don't have such a beneficial power pricing scheme in Oz but no matter where you are in the world from what I have seen, there is NO where in the world batteries make any sense right now nor will do for the forseeable future.
The price would have to be about 1/3rd of what they are now to get in the ball park no matter what you pay for power.
Some places have batterys than others but where the batterys are cheaper the power is too canceling out any ROI advantage.
I have seen all sorts of convoluted, complicated and green washed calculations to try and prove otherwise but the equations is very simple.
At 100% utilization 100% of the time, they simply cannot save enough power for it's value to repay it's cost in a valid time frame being the lifetime of the battery. The exception maybe a DIY system using forklift packs or the like but certainly no Powerbore or similar plug and play type battery has any valid Financial benefit.
Oh yeah, we can spin doctor the argument as well and say I bought one for blackout power which,
1. is still not saving power and is a totaly different scenario, and,
2, You are a fool for paying far too much for an overpriced solution when there are far better and cheaper alternatives.
If you buy a battery to "save the environment", Well I won't nominate fitting and applicable names but lets just say you are either a product or sucker of the PC greenwashed.
I bought 3 Diesel engines this week and 2 Generator heads. All working or brand new. $300 all up. One needs a new belt, the other would need the head and the engine mounted and hooked up. Lets play devils advocate and call it $200 to make a nice Figure of $500. Where a battery lasts hours, I can run everything and lot more than a battery can till the cows come home..... in 6 months time. And I still have a spare engine.