Best Way to Decide Which Battery Bank to Use with Your PV Solar System
When you want to go off the
grid with your PV solar system, you’re going to need a battery bank to store
potential energy. Lead-acid batteries dominate the market when it comes to
solar PV systems. They’ve been available for years and have the same look as
car batteries. The operating principle involves using deep-cycles to produce
small shots of prolonged energy.
Other than the most
widespread flooded lead-acid kind of battery, a few more alternatives are out
there such as gel-cell and sealed absorbent glass mat (AGM). The weakest part
of any PV solar system is most often the battery. This is because they wear out
faster than any other part and lower performance at the same time it is
happening. Make sure your system is in top shape with a high caliber battery.
Choosing the Right Battery Bank
1. Figure out the number of
watt-hours your unit is going to consume by referring to our article on how to
size your PV solar system the right way.
2. Determine the number of
days you want in energy for your system. One question you can consider is
“how significant is autonomy to me?” Is being tied to the grid
alright with you? If this is the case, batteries aren’t even something you
need. After you figure out the answer to questions like these, choose the number
of storage days you want and need. The majority of systems are made to fit 1-5
days of storage power.
3. Figure out what kind of
battery is right for your situation.
4. Because lead-acid
batteries usually lose 20-25% of their storage capacity in temperatures that
reach 30ºF, intend to keep them someplace warm. The ideal temperature is
between 50-85ºF and 77ºF is the perfect temperature. When storing them
someplace warm is not in the picture, buy extra batteries as a safety measure.
5. The more you can simplify
your battery bank choice, the better it will be. Pick one with a single series
string of cells. There is less of a chance of something going wrong than with
one with multiple strings. There also more convenient to replace if broken.
6. If you see yourself
upgrading your system with more units in the future, purchase a bigger bank
than you feel is necessary. You can’t expand this part as easily. Straining
your battery bank is a surefire way to have a condition marked by chronic
undercharging. This can also create a situation where the batteries fail
earlier than normal. Try to fill your battery bank up to 30-40% more power than
is needed for the current demand.
Purchase a battery monitor
system (BMS) and set it up where you can see it easily. These kinds of tools
for battery management has the ability to extend the lifespan of your batteries
and give you an easier time with maintenance.