Micro-Hydro System Batteries
Micro-hydroelectric systems use a kind of battery called a lead-acid deep cycle battery. You might wonder why you would even need a battery for a micro-hydro system - isn't the water running constantly, producing energy constantly? Yes, but you are not using energy consistently, so your battery or battery bank can compensate for those times when you are using more energy than your micro-hydro system is producing.
The lead acid deep cycle battery used for your micro hydro system is very different from a conventional car battery (also called a start battery).
Adding a battery bank to your micro-hydro system just might guarantee you a never-ending supply of energy.
The lead acid deep cycle battery is designed to be very tolerant of ongoing (even daily) charging and discharging.
A lead-acid deep cycle battery also costs far more than a conventional battery. A micro-hydro system's battery might likely discharge once or twice a day - at times of peak energy usage (e.g. morning, supper time). Batteries used by a micro-hydro system will last longer than those used by other energy systems, as they will not discharge as deeply and as frequently. Wind and sun might die down for days at a time.
Battery size system
You need to consider the size of your battery system, as well. If you use small batteries, you run the risk of discharging them too often, and so you will have to replace them. A battery properly sized for your system and well maintained will last 10 to 15 years-well worth the investment in money and time.
Depth of discharge
Depth of discharge is a measure of how much energy has been taken from a battery. The lead-acid deep cycle batteries used in small solar and wind power systems are much more able to tolerate discharges, as compared to regular car batteries. A 50% to 80% discharge of your solar or wind energy battery will be tolerated by the lead-acid deep cell battery.
There are several kinds of deep discharge batteries, of which flooded cell batteries are the most common. These can withstand overcharging, are low cost (compared to others) and are built to have a long life.
Other kinds also have their advantages and features, including the following:
- Sealed flooded cells are maintenance free but can be damaged by overcharging.
- Recombinant flooded cells are more expensive but will not spill acid.
- Gelled electrolyte cells are also expensive and are more versatile in mounting.