batteries and backup systems for wind, Hydro and pv solar

Off-grid electric wind systems demand a battery bank: a set of batteries wired together to store energy for non-windy days. Similarly, PV solar systems and hydro systems also require a battery bank, to face wide periods of meager sun or water resources.

Size

These battery systems are usually sized to keep home electricity running for two or three non-windy days (in the case of wind systems), or, say, a week of non-sunny days (in the case of solar PV systems). But all depends on the local wind, solar or water trends.

Types of batteries

Battery Lead-acid batteries are the most common. The cheapest lead-acid batteries are the flooded type, but they have a disadvantage: they demand the addition of distilled water whenever there is loss of water during charging.

Sealed gel-cell batteries (freeze-resistant batteries) are a good choice in cold climates and in freezing spaces. Non-deep-cycle batteries aren’t suitable in small renewable electric systems.

Battery storage lifetime

The typical lifetime of a battery storage system is around 6-10 years (depending on their type), which is much shorter than the lifetime of the structures and hardware of the wind, hdyro and PV solar systems.

Backup engine-generators & Off-grid wind, Hydro and pv solar systems

Backup engine generator for wind and solar systems Off-grid wind, hydro and off-grid PV solar systems rarely run without an engine-generator fueled by gasoline, diesel, biodiesel or propane. This backup system is crucial for long non-windy and non-sunny or little-water periods, though they will typically run only for short periods.

Sizing the battery and the backup fuel systems

It is possible to size a small solar or wind system and a battery bank to cover long adverse non-charging periods, but that is obviously expensive.

Batteries and other back-up elements are typically sized for 1 to 3 days of function, but the final solution will always depend on the cyclical patterns of the natural elements in your site.

A hybrid wind-PV solar system is a good way to avoid a large backup fuel system, and that for obvious reasons: the occurrence of simultaneous non-windy and non-sunny days for significant periods is much less probable...