Solar water pumps work for small fountains, but in my experience have a shorter life than electric pumps. I used one for a pot fountain, and was satisfied with it, but it quit working after about 18 months? 2 years? Something like that. Eventually I replaced it with an electric pump. This was several years ago, maybe they are better now.

I think we all pay attention to it but do so indirectly, not in any formal or scientific study sense. But we consider it indirectly in the gardening aspects of picking the best sunny yard spot for the garden, E-W bed orientation when possible, plant placement to avoid shading of other plants or plant placement to provide some shade for other plants, ambient air temp dictated by the sun and its effect on plants, deciding when to water or when to apply foliar sprays, etc. Home gardeners don't have the cultural control advantages that large commercial growers do. We don't have the acreage, the equipment, the working staff, the funds, or even the need to produce for corporate profit they have. So we make-do with what we have and work to control what we can. The rest has to take care of itself. ;-) Dave

Came to this site hoping someone found decent quality solar garden lights. My experience has been that they are junk and a waste of money with fails right out of the box, more fails within a month and all fail not much after that. I guess low wattage hardwired is only way to have reliable lighting. You'd think by now, solar would be more reliable and better quality but I guess, people keep buying and replacing them so why would mfr improve the quality. Very frustrating.

Sorry this post is long. If you get too bored, just skip to the next-to-last paragraph. So far nobody has yet found the perfect battery. All of them are balances of cycle life, cost, safety, temperature range tolerance, specific energy (Wh/kg), energy density (Wh/l), specific power (W/kg), charge efficiency, and probably some factors I've forgotten about.. No one battery type has them all nailed down, and probably none ever will. The battery that might make its way into a home power system today would most likely be lead or lithium ion. A few others have been used but are now mostly on the sidelines. These include nickel cadmium, nickel iron, and nickel metal hydride (which is really just improved nickel iron). Lead is the traditional battery for home power systems, but it has significant downsides. Specific energy and energy density are low. Flooded types need watering and periodic testing. Cycle life is good for heavy, expensive tubular plate types, not so great for conventional flat plate batteries. Lead used to be the uncontested leader in cost per watt-hour delivered, but in recent years lead metal prices have increased and it's no longer as competitive as it once was. Nickel iron is legendary for extremely long cycle life. I've read that some of the original NiFe cells built by Thomas Edison are still in service! Their specific energy and energy density are better than lead, but not dramatically so. Efficiency is a weak point because they gas too freely (too much energy going into electrolysis), and this also requires careful ventilation. The few NiFe manufacturers charge nosebleed prices, which limits their use. Nickel cadmium has long cycle life and decent specific energy and energy density. Their big problem is that cadmium is nasty, toxic stuff. Because of this they face severe restrictions in the EU. Nickel metal hydride batteries have sort of been lost in the lithium shuffle in recent years. They have long cycle life and quite good specific energy and energy density. The problem has been that they're encumbered by restrictive terms issued by the patent holder, but I think the relevant patents may expire later this year. The other big negative with NiMH, as with other nickel chemistries, is that nickel is expensive. If given a chance, I think NiMH could still become competitive, but don't hold your breath. Recently lithium ion batteries have grabbed the spotlight almost to the exclusion of any other type. Note though that they aren't all alike. There are several different chemistries with different balances of those concerns I mentioned above. Beyond that, each chemistry is optimized differently by different manufacturers with different design goals. In general I'll agree that lithium ion can be a bit touchy about temperature, certainly more so than lead. Some lithium ion cells shouldn't be charged below freezing (0C / 32F). Others can accept a charge down to -10C, and a few are OK as low as -30C. Again, it depends on what the battery manufacturer is optimizing for. In most home power systems this isn't a problem, especially if the battery is located in conditioned space. The battery's own internal resistance will keep it warm with any normal current use. Insulation and controlled ventilation will keep the temperature in the acceptable range. OTOH very warm temperatures can reduce lithium batteries' cycle life. The more fully charged they are, the more they suffer. So you limit the charging rate at low temperatures, charging slower and slower as the temperature falls, and eventually not at all. On the upper temperature end, you don't charge the battery completely if you expect, or already have, very hot temperatures. Because lithium batteries are fussier than other types about over-charging and over-discharging, they almost always are sold with battery management systems (BMSes). Good lithium ion BMSes know what their batteries are capable of. They monitor the cells' state of charge (or at least their voltages, which is not quite the same thing) and usually also temperature. They control the charging and discharging functions to suit, for a compromise between capacity and cycle life. To cut to the chase, based on Tesla's track record (no pun intended) with their cars, I expect that they'll be more than competent when it comes to their Powerwalls' battery management. As for whether a Powerwall or two can store enough energy for your household needs, that depends on many factors, including how you heat and your overall energy efficiency. Most off-grid folks have to make some lifestyle adjustments when they're no longer drawing their energy from an apparently bottomless source (the grid). If they don't, it probably means their pockets are pretty much bottomless. :-\