The NIFE, inefficiencies as defined by you are not a problem if proper planning is in place.

FerroNickel or NIFE batteries are a bit lower efficiency than LEAD ACID, in reference to POWER-IN / POWER-OUT - THOUGH the life of the battery is extremely long.

The discharge rate, indeed higher, and water usage higher are the main problems -- those are not in-efficiencies are just the natural behavior of the battery conversion and storage capabilities.

Another one is that the upper voltage, when the battery is fully charged, grows to 1.57 volts/cell and in some cases the charging source has to be higher to accomplish total charging mode.

Gassing can be reduced if the charging current is reduced when the gassing point is reached, we had internal battery pressure increase detectors to reduce the charge to a level that gassing was not longer a problem -- the caps were home made with a switch set for a raise of PSI pressure increase to detect the gassing, then once all were detected time wise, the strings were re-arranged for equal pressure behavior to stop heavy charging and go for soft charging below gassing which some times represented around 40 to 40 % of high level charging.

You may see this as battery management, process that was and it is still quite effective since the batteries are around 100 years old, imported to my native country, around the early years of the 1900's for the family farms -- as I understand there are at least two farms with battery banks.

The main thing is to make sure that the KOH+Lithium does not get oxygen.

The charger had a secondary loop with higher voltage with a low current limiting setting to maintain the voltage high without discharging -- indeed the charging system are small hydros, and even now with rural electrification the banks are kept because the GRID drops are common and long time to reset ON.

I do not recall the amp-hours.

If you have a 12v/80Ah battery bank, it can store about 1kW, and it costs about €120 or so.  Being lead-acid, it stores most power when you discharge it by about 30%: more than that, and wear gives too few cycles; less than that, and you get more cycles but they are so shallow you don't store as much charge.  A typical lead-acid design is good for 3000-4000 cycles at 25%-30% discharge.  Let's be generous and say 4000 cycles at 33%.  That gives a total storage of 1333kWh over the entire life of this battery, and so a wear cost of €0.09 per kWh.

Now Edison batteries might only store 75% of the energy of a lead acid battery, but to all intents and purposes they don't wear.  (We are sure they do wear, but since some of Edison's original 1910 batteries are still in service, it is difficult to measure how much they wear.  Certainly the wear is very small.)  So a 12v/80Ah Edison battery is going to waste 25% of its energy, then over the 1333kWh life of the lead-acid battery, it's going to waste 444kWh.  Now if generating your 444kWh costs more than €120, you've lost money.  If it doesn't, you haven't.

If your situation abuses batteries more than this perfect setup (and Edison batteries don't seem to care about being run flat) then you should consider the other scenario: the above lead-acid battery can be run flat about 400 times before it's scrap; storing 400Ah in the process.  Using 400Ah out of the Edison battery wastes 133Ah; which again has to be generated cheaper than the €120 for the lead acid battery.

Where I live, the local supplier provides cheap rate electricity at about €0.08 per kWh, and they're threatening to increase that to €0.10 per kWh.  So 444kWh costs €35.56, shortly to go up to €44.44; and 133Ah costs €10.67, shortly to go up to €13.33.

If I buy a diesel generator and run it on heating oil, I pay €0.65 a litre for oil. (I can buy generic vegetable oil from Tesco for about the same price, if I prefer not to contribute to foreign policies like Iraq.)  Now a diesel generator gets maybe 2.5kWh - 3kWh out of a litre of heating oil: giving a price of €0.22 to €0.26 per kWh, ignoring the cost of maintaining the generator, but also ignoring the benefits of recovering waste heat to provide hot water or home heating.

Petrol generators are more inefficient than diesel ones, and the fuel is more expensive, since it normally has road tax on it.  Petrol generators around here cost about €0.50 per kWh for fuel.

But if you can generate electricity for cheaper than €0.27 per kWh (€120 for 444kWh), it is certainly cheaper to use Edison batteries and buy more windmills/solar cells/heating oil.

If you can generate electricity for cheaper than €0.90 per kWh (€120 for 133kWh), it might still be cheaper to use Edison batteries and more generating capacity, depending on how deeply you discharge them.

Even the initial outlay is not as much as it seems, as you might be able to divide the size of your battery bank by 2 or 3, since deep discharges are not the tragedy that they would be with lead acid.  With Edison cells, you only care about depth of discharge when the lights go out.

Then there are the environmental benefits of not having nearly a ton of poisonous heavy metals on the property, that have to be disposed of every decade or two.  And the environmental benefits of not having to manufacture new batteries and recycle the old ones.  But those benefits are harder to quantify.