Two weeks or more of cloudy and windless days are not unusual in some equatorial regions and that causes solar lighting and solar powered freezers to fail.

Nickle Iron batteries sound like they are perfect but when looking into them it seems they are somewhat extra costly to manufacture, they are more heavy, slow to charge, only able to discharge slowly, should not be charged from a constant voltage (solar is constant), and very importantly they really require charging every day (and sun and wind does not occur every day).

http://en.wikipedia.org/wiki/Nickel%E2%80%93iron_battery

Pacific Islands JF?

I'd have thought you would have put wind power coupled to Bazz's Nickel iron batteries on the menu or top of the list?

Given for most Islands the wind blows fairly frequently but only as a constant variable; meaning turbines with blades that can be altered to shed some of the wind or utilize every last puff of it?

And given wind as a constant (on again off again) variable, extend the life of nickel iron batteries to the claimed forty years?
A.B.

JF Aus, I had not read that article on wiki previously.
I think with computer control of charging just about all the problems
you mentioned could be overcome.
I note that a 300% charge rate can be used for periods of 30 minutes.
I did not see the reference to a constant voltage charge source.
In any case computer control could adjust the charge profile for
longest life. I think the loss due to the internal resistance can be
offset by the lower annual cost of the batteries over many years.
There is a company in Sth Aus that supplies them for solar systems;

http://www.ironcorepower.com.au/page3.php

I do not know if they are manufactured in Sth Aus.
I have not had any experience with NI cells so I only know what I have read.

Alan and Bazz,

Yes, the Pacific Islands, Solomon Islands.

Most villages are situated in calm wind free areas.
Lagoons generally are lagoons because they have formed in virtually wind free conditions that provide water calm enough for coral to grow without being pounded by wind driven swells and surf.

Where other villages are situated without a lagoon those villages are tucked away to escape wind. Wind can blow houses to pieces or be otherwise annoying.

Present solar systems are computerised and designed to shut down outgoing power before the battery goes flat, and they shut down the solar input to stop battery overcharge.
So yes computers can control solar, but.

But when a battery eventually fails or wears out the computer components invariably fail because they cannot cope with the strange low and erratic voltage, such as a fully charged say 10 volts jumping up to 12 volts and back to 10 as one cell dies, eventually completely. Anyway the computer fails.

Then, some of the gel batteries don't last 2 years and they cause computer failure.

Most people in developing countries cannot afford batteries for a torch or radio. Cost of electric cable to wire a house or to run cable from a windy hilltop wind generator, is out of the question.
Even in Australia solar panels are unaffordable to many people.

People with money can afford alternative energy components but I think most of those people prefer to plug into the city/town power supply instead of messing with alternative energy.

Continued…………..

Cont’d……..

I think power companies have done well filtering or scrubbing soot from furnace fires, and air pollution has been greatly reduced.
I think effort to overcome air pollution should continue.
But what about the whole world ocean?

I think the biggest problem is sewage and land use nutrient pollution feeding algae but this is being ignored by the AGW fraternity.

NASA photos clearly show cloud forming above visible algae blooms. I have put up links on this site showing those NASA photos.
There should be no doubt that ocean and lake algae is being fed and grown (proliferated) by human sewage and land use nutrient pollution.

In other words, there is need to harness nutrient to viably produce algae for biofuel instead of messing with toxic batteries and windless cloudy days.

I have heard nutrient trading is possible.

JF Aus;
Cell monitoring can be done with a small module fitted to each cell.
They are cheap & off the shelf. Require two wires from each cell
to the scanner. The Nissan leaf has such a system and alarms if a cell
is below spec. A friend converted his car to electric and he installed
such a system.
You can make the monitoring as complex as you wish by reading the cells
and controlling the charge voltage and current.
It is a well established system and the hardware is all off the shelf.
You could even disconnect a cell if it really failed but that would
probably need a relay for each cell.