Page 52 - Green Builder January 2017 Issue

ENERGY S0LUTIONS
Sustainable Power From This Day Forward
Life Lines
A longer-lived solar storage
battery starts with starts with
proper charging and maintenance.
BY MATT POWER
AT THE RESILIENT LIVING CAMPUS in Pine River,
Minn., technicians have developed a system that
optimizes lead-acid batteries used for solar energy
storage.
“We’re interested in both home storage and RV
systems,” notes Dan Pavek, the young technician
studying battery dynamics at Hunt Utilities Group’s research center
(www.hugllc.com). He’s inside the “ManiShop,” a passive solar
warehouse-sized building with a living roof and more other green
features than can be easily listed here. “A large RV has about six big
batteries in it,” Pavek continues, “and we’re hearing from owners that
they typically get only three years of solar storage before they have
to replace them. We want to try to double that.”
Pavek knows this isn’t the end game for cleaning up the footprint
of battery storage, but he sees it as an important upgrade that
will bridge the gap to other, cleaner forms of batteries now in
development—such as algae or silicon-based technology.
The group’s approach to lead-acid batteries is sophisticated.
It’s easiest to pull a little of Resilient Living’s online explanation
(http://bit.ly/2gNOwzR). Among the challenges HUG is trying to
address in its solar-heated ManiShop research building:
¦¦ Batteries in series or in parallel must be well balanced, or they
destroy one another. If one battery begins to fail, it is stressed the
most, accelerating the failure process. This can result in a catastrophic as the weakest battery, the Battery Socializer employs microprocessor
failure, and possibly fire or property damage.
¦¦ Under current practices, batteries cannot be swapped out
individually—the whole bank must be replaced. This generally is a
large expense to the owner of the system.
¦¦ Batteries in a series are only as good as the weakest battery
installed. For example, if you add a new 100 percent capacity to a bank
with other batteries that can only put out 80 percent capacity, the new
battery will end up chronically undercharged, shortening its life. Also,
the older cells become the new weak cells and deteriorate quickly.
¦¦ Lead-acid cells require careful charging and maintenance
to maximize their life cycle. Most systems require a technician to
manually analyze, monitor and perform this maintenance, which
carries a significant labor expense.
50 GREEN BUILDER January/February 2017
CREDIT: GREEN BUILDER MEDIA
Wiring matters. At the Hunt Utilities Group Resilient Living
Campus, batteries are arranged in various configurations and
tested for output, recharge and long-term performance. The goal
is to “socialize” lead-acid batteries to optimize longevity.
¦¦ All types of batteries have their own maintenance requirements and
charging parameters. Technicians and engineers have to be specially
trained for each type of battery that they are required to maintain.
TRADITIONAL BATTERY BUS WIRING
Traditional battery bus systems require heavy conductors and
connectors capable of handling the maximum current of the batteries.
Typical applications today employ batteries that are wired in series,
or some combination of series/parallel.
As is often the case in homebuilding, sometimes the most
significant advance in efficiency is the one right under our noses.
Too often, for example, builders focus on higher level engineering
details such as R-value and glazings before addressing big design
impacts, like siting and building orientation. In the case of batteries,
this research seeks to demonstrate how less-efficient wiring methods
and lack of individual monitoring of batteries can lead to early
failure. The end result of this research is the Battery Socializer
networking system.
Unlike traditional battery banks in use today that are only as good
control of each battery along with a voltage abstraction system to
monitor, optimally maintain and protect each battery in the bank
individually. The result is extended battery life, the ability to replace
only defective batteries, add capacity as needed, and the ability to
mix batteries of different types and conditions. GB
To learn more about HUG’s research, visit www.hugllc.com.
For more about resilient housing and homes that
are “ready for anything,” visit the Resilient Times website
(http://resilienttimes.com/).
www.greenbuildermedia.com