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| Batteries |
New Technologies
There have been several advances in battery technology over the last few years.
Unfortunately, they are not yet available in an affordable manner for large
scale use in alternative energy systems.
The Ovonic Battery Company (which is part of the same family as Uni-Solar) is currently gearing up for production of a battery used primarily in electric vehicle applications. This Nickel Metal Hydride (NiMH) battery boasts a fast recharge capability (up to 60% capacity in 15 minutes), ability to deliver high current without dropping cell voltage and most significantly these batteries weigh half as much as lead acid counterparts. We will continue to monitor these advances in battery technology and will add these to our product line when they become readily available and affordable.
Temperature
Ideally a battery bank should be protected from cold and be maintained at a
constant temperature. Battery capacity is significantly reduced as temperatures
decrease. For example, if a battery is rated as 600 a/h at 60ÉC, its rating
will drop to 300 a/h at -20ÉC. Batteries must be derated when operated in cold
climates. Protecting your battery from cold temperatures will improve the
performance of your electrical system.
Capacity
The capacity of deep cycle batteries is measured in amp / hours (a/h). The rate
of discharge affects the total capacity. The slower the discharge, the higher
the capacity. A 20 hour discharge is often used when labeling a battery for
renewable energy use. However, 72 or 100 hour rates are sometimes used. A
battery rated at 800 a/h at a 20 hour rate can sustain a discharge of 40 amps
for 20 hours before it is completely discharged. When purchasing a battery
bank, one should consider price, quality, battery bank size, length of expected
service, and weight.
Battery Installation
Generally, batteries receive sufficient protection from west coast weather
conditions if they are placed in an insulated box adjacent to the house. In
other parts of Canada, many people place their batteries in an underground
insulated box. This is a good way to protect them from freezing weather but the
pit must be well drained.
Batteries may be installed inside a home if they are vented to the outside. When batteries are charging they give off hydrogen and other gases, which are explosive, corrosive, and foul smelling. To minimize the risk of fire, batteries must be in a vented compartment separate from any other electrical components.
If battery cables to the inverter are run in conduit, it is necessary to seal the conduit at the battery box to prevent gases from rising up the conduit and reaching the other electrical components. Even Gel cells, which are sealed, should be kept away from sources of flame, sparks and heat. Batteries should always be installed so children do not have access to them.
Battery Care
Keep terminals clean and tight.
Keep batteries charged. Do not store them in --discharged state.
Periodic equalization is needed, especially with deeper discharge cycles.
Avoid totally discharging your batteries. This shortens their life considerably
Inspect cells every three months for water loss.
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