Page 60 - North American Clean Energy November December 2015

energy storage

A custom designed, vented box, made to push
in cool air and exhaust built-up heat
Keeping Batteries Healthy in

Hot and Cold Weather

by John Connell

renewable energy system performance and battery life. advances here is Cast-on-Strap (COS) assembly, which allows for 4,000 adjustments versus
EXTREME TEMPERATURES SLASH
Fortunately, just a few simple steps can save headaches, maximize lifespan, and avoid
just 40 for hand welding. Finally, select deep-cycle batteries designed for renewable energy
the need for early battery replacement.
systems, rather than car batteries or non-RE batteries, for maximum power delivery and
life. (See July/August 2015’s “How to Select the Right AGM Battery” for more information.)
Heat and cold compromise lifespan and performance

Batteries are rated at roughly 77°F, and perform best between 50°F - 85°F. But many 4) Know the depth of discharge
batteries are routinely exposed to temperatures from freezing to well over 100°F. At colder To avoid shortening battery lifespan, never discharge batteries below 80% depth of
temperatures, batteries typically lose 10% of their capacity for every 15°F - 20°F below discharge. (50% depth of discharge is preferable.) Batteries typically lose 10% of their
80°F because internal molecules slow down. Excess heat shortens battery life because it capacity for every 15-20°F below 80°F. his means there may be less storage available

accelerates corrosion and causes battery luid to evaporate, which damages battery grids. than anticipated. If batteries continually discharge too deeply, consider adding additional
For every 15°F average operating temperature over 77°F, battery capacity increases, but battery banks to create a safety bufer and increase lifespan.
lifespan is cut in half.
And conventional battery storage approaches, such as storing batteries outside, or 5) Closely monitor the battery bank at irst

in tin shelters, refrigerators, or makeshift boxes compromise battery life even faster. To ensure batteries are properly calibrated to the system and performing optimally, they
Temperatures in enclosed spaces, for instance, can exceed 140°F.
should be inspected once a day for the irst two weeks with a voltmeter and hydrometer.
Addressing variables at the beginning of battery use will minimize the chance of damage to
Six keys to longer battery life in any climate
the battery bank and protect the investment in the system and batteries.

1) Protect batteries from the environment
Keep batteries in a location where temperatures stay between 50°F - 85°F degrees. For When the charge controller indicates the batteries are fully charged:
AGM or other low/no-maintenance batteries, storage in the home can work well.
• Let batteries settle or “rest” for at least 4 hours, to establish equilibrium;
For looded batteries, a vented box with a lock in the shed or garage is a good location. • Use a digital voltage meter to measure voltage across each individual battery; voltage

Enclosures must ofer easy access for maintenance. Never install spark-producing devices should read AT LEAST 2.12 volts per cell (VPC);
in the enclosure because they could ignite an explosion during charging.
• Use a hydrometer to measure speciic gravity of electrolyte in each cell; speciic gravity
Batteries should be arranged so they’re the same temperature. Leave air gaps of roughly should measure AT LEAST 1.265 or higher;

2 inch between batteries to prevent their cores from getting warmer. If batteries are near • If both voltage and speciic gravity readings are not as indicated above when the charge
an exterior wall, insulate the wall and allow room for air circulation.
cycle completes, adjust the controller settings as necessary, until above readings are
And be sure to properly ventilate batteries following the National Electrical Code, Article attained by the end of the programmed charge cycle.
490.9(A).

When batteries must be exposed to low temperatures, buy a larger battery bank to make 6) Perform regular maintenance
up for decreased capacity. And avoid direct sunlight, since it can warm some cells more Even low- or “no-maintenance” batteries need to be inspected regularly to make
than others.
sure they’re performing properly. Battery manuals ofer guidelines and schedules for
For a more comprehensive solution, a standalone system such as the EMPUS maintains maintenance. Here are some quick keys:

ideal operating temperatures and maximizes life. (See Jan/Feb. 2014’s “Power to the People.”)
• Always remove jewelry and wear protective eyewear, long sleeves, and gloves before
maintenance;
2) Choose the right battery type for the system
• Put routine maintenance in the calendar to make it automatic;
Every battery type has advantages and disadvantages. Lead-acid batteries are the most • Clean battery terminals with a scouring pad or brass brush to remove corrosion, rust, or

popular because they’re afordable, reliable, up to 97% recyclable, and proven for over 100 oxidation; otherwise, build-up can drain battery power;
years. hese batteries require regular maintenance and are heavier, though.
• Check that luid is covering your battery plates inside, to prevent sulfation. If water levels
Absorbent Glass Mat (AGM) batteries ofer low internal resistance, long service life, and are low, add distilled water until plates are covered.
high current delivery. heir cost per amp-hour is greater than looded batteries, but they’re

extremely low maintenance.
Even the best batteries struggle when exposed to the elements. But choosing the right
Lithium-ion batteries have the highest power density and are extremely low batteries, then maintaining and protecting them, will ensure maximum longevity and
maintenance. However, this newer technology is more temperamental and prone to ires, performance for years to come.
in part because of its power density. It has a higher cost and is rarely recyclable.

John Connell is the vice president of Crown Battery’s SLI Products Group. Crown Battery
3) Select batteries built to last
manufactures all its advanced technology batteries at its ISO-9001:2008-certiied plant in
Even among batteries with similar speciications, construction methods can have a huge Fremont, Ohio.
impact on lifespan. For instance, thicker plates in lead-acid batteries provide more material

for chemical reactions, which improves longevity. Automated production increases Crown Battery | http://www.crownbattery.com
precision, reduces corrosion and maintenance, and improves lifespan. One of the biggest

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