Page 21 - PS Battery Guide May 18

Battery guide For PowerSpout

You should always take care when working with batteries. Burns,
acid splashes and even electric shocks can occur. If you do not have
sufficient skill and/or experience to install and care for this
equipment you should engage a renewable energy professional to do it for you.

Battery explosion hazards
On a day-to-day basis the largest danger is explosion of
the gasses within the battery itself, and not within the
battery enclosure. Extreme care is required to avoid
sparks in the vicinity of the battery that might ignite
gas and cause a fire or explosion. Often too much
emphasis is made about removing the gas from the
enclosure and not on good working practices.

Do not install any fuses in a small battery enclosure, as this is a potential source
of ignition.

Take care that the wrench/spanner handle does not bridge between terminals
when connecting batteries as this can cause arcs, burns and explosions. Insulate
all tools with insulating tape prior to any work on your battery bank.

A well-ventilated enclosure to outside air will help to reduce battery
temperature on hot days and in the very rare event of an internal battery short
allow the explosive mix of hydrogen and oxygen to quickly leave the enclosure.

Due to the small risk of explosion and fire, batteries should be installed in a
locked and ventilated enclosure, not within dwellings.

Example of real life experience
The author of this section was once on a site where a client accidental dropped a
large spanner on the battery terminals that then became wedged. Almost
immediately the sparks from the shorted spanner ignited gases at the battery
vents. After 2-3 seconds the first battery in the string exploded showering the
owner in acid. As the owner turned to run out of the battery shed the second
battery exploded. This second explosion sheared off the battery terminals and
the short circuit was broken.

Fortunately help was quickly on hand to wash the client of battery acid as the
client was in a state of severe shock and unable to help himself or comprehend
what had just happened.

The fire extinguisher in the battery room was quickly used to extinguish the fire
that was being fuelled on hydrogen and melting plastic of the battery cases.
Helpers on site quickly cut through the battery links to make the site safe, as at
this stage is was not known to them what had caused the explosion.

The battery bank consisted of 2 x 48V DC strings of 500 amps hours each. The
bank was in an adequate enclosure, but once the lid was opened there was no fall
protection on the battery terminals.

© 2018 EcoInnovation Ltd (NZ) Page 21
Last reviewed 19/6/18