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<DIV><FONT size=2 face=Arial>
<DIV><FONT size=2 face=Arial>First of all, there is no one solution to battery
selection, installation, operation, and maintenance. One size does not fit
all. </FONT>Allan and other wrenches with lots of battery experience
have a good understanding about batteries in their regions
for their customers.</FONT></DIV></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Second, insulation is used to control temperature
change. Insulation slows both heat loss and gain. Large battery banks tend to
change temperature slowly due to their mass and may not need insulation in your
region or in a specific installation. The goal is to keep the battery bank
at its optimum temperature. Cold batteries have reduced capacity. 40 F (4.4 C)
is too cold for almost all RE system batteries. Hot batteries have shorter
lives. Heat affects both battery chemistry and materials. For example, the
plastic around Absolyte terminals cracks if their temperature is
repeatedly 90 F (32.2 C) which can happen in an uninsulated battery
area in the southwest U.S. So too hot or too cold is not good.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Third, batteries need ventilation to safely remove
hydrogen. Surprisingly, what most people consider a small amount of battery
ventilation will suffice unless the battery bank is being charged
excessively. For example, a PV system with eight 100 watt modules (rated 17.1 V,
5.88 A) and sixteen 6-volt batteries is wired for 24 volts DC. The required
venting is 0.0135 x (5.88 x 4) x 12 = 3.81 CFM or 228.6 cubic feet per hour.
Many, if not most, rooms are 8 feet in height with 2 air changes per hour.
A room 8’ x 6’ x 6’ has 288 cubic feet volume and naturally vents 576 cubic feet
per hour, almost 2.5 times the required 288.6 cubic feet per hour.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>In general, a battery area, room, box,
etc. should be kept at 70 F (21.1 C), have good ventilation, no open
flames (heater, gas water heater nearby?), no electrical sparks (automatic
igniters, etc.?), easy to maintain and inspect, tidy, out of reach of
non-authorized personnel, and have an up-to-date fire extinguisher
handy.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Batteries operate by electro-chemical process
almost like living things. If they are too hot or too cold, they perform poorly
and can die. If they are not fed properly (charged correctly), they will
die. Interestingly, we use expressions like "die" and "end of life" to
describe these non-living things. Most wrenches know
people who party all weekend, don't eat well, forget to dress properly
for the weather, and get sick. Likewise, if a battery bank is
deeply discharged, not properly recharged, and too hot or too cold, it will
perform poorly and die prematurely. You get the picture.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Lastly, we have learned a lot about batteries
in the 200 year since physicist, Allessandro Volta, developed the first cells.
Unfortunately, a lot of battery myths exist. Explode myths (but not batteries)
by asking the "5 whys". See <A
href="http://en.wikipedia.org/wiki/5_Whys">http://en.wikipedia.org/wiki/5_Whys</A></FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Joel Davidson</FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=dan@foxfire-energy.com
href="mailto:dan@foxfire-energy.com">dan@foxfire-energy.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=re-wrenches@lists.re-wrenches.org
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, December 11, 2010 5:32
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [RE-wrenches] To insulate a
battery bank -- sort of</DIV>
<DIV><BR></DIV><SPAN
style="FONT-FAMILY: Verdana; COLOR: #000000; FONT-SIZE: 10pt">
<DIV>Ok, I'm a little reluctant to kick this critter much.. because I feel
like I must be missing something here... but let me float this notion.. If we
<SPAN>stuff<SPAN id=GD__CURSOR> </SPAN></SPAN>flammable gas producing
batteries in an enclosure (and proceed to button them up tighter than a bull's
ass in fly season -- fan or no fan), Haven't we just created a Class I
Division 1 location? (NEC 500.5). then say we do rely on a $4. fan (OK
-- $15.) to declassify as allowed in 500.5(A)fpn, Wouldn't we still have
a Class I Division 2 location? NEC 500.5(B)(2)(2)/(3)<SPAN>.<SPAN
id=GD__CURSOR> </SPAN></SPAN>So my point is -- are fully enclosed battery
boxes really w<SPAN></SPAN>orth the hassle? are they even A good idea? I can't
seem to find where NFPA 70 "Requires" a battery enclosure.. 690 VIII
says you need to protect electrical connections (in dwellings) and
<SPAN><SPAN>kicks you back to 480<SPAN id=GD__CURSOR></SPAN></SPAN><SPAN
id=GD__CURSOR></SPAN></SPAN>, but makes no mention of "requiring" a battery
enclosure.. 480.8 says basically that if you use racks or trays, they've got
to hold up. 480.9 outlines ventilation and working space, but again doesn't
"require" enclosures. (480.6 deals with Insulation of batteries.. But I'm
thinking they're talking about <SPAN>electrical<SPAN id=GD__CURSOR>
i</SPAN></SPAN>nsulation)... But nowhere in the NEC have I found any mention
of battery boxes or Enclosures being "Required".. On the contrary, Seems
to me they're suggesting that if by design you can provide for proper work
space, adequate ventilation (both out and in) and protect the electrical
connections, you're good as far as NEC is concerned.. <SPAN>In NFPA 70E,
(Workplace Safety) 320.4 says batteries should be under lock and key (or
require a tool for access), and that they be protected both physically and
electrically. <SPAN><SPAN>
<SPAN><SPAN><SPAN><SPAN>also</SPAN></SPAN></SPAN><SPAN id=GD__CURSOR>
</SPAN></SPAN>in NFPA</SPAN><SPAN id=GD__CURSOR> </SPAN></SPAN>70E, 320.6
kicks around enclosure requirements some, but seems to focus more on
protecting terminals and related equipment.. <SPAN
id=GD__CURSOR></SPAN></SPAN>Now in OSHA 1926 (Subpart K),
<SPAN><SPAN>.441</SPAN><SPAN id=GD__CURSOR> </SPAN></SPAN>seem<SPAN><SPAN
id=GD__CURSOR></SPAN></SPAN>s to be where "required enclosures" originates,
but again, it seems to be referring to commercial workplace safety... (i.e.
also requires that "the charging apparatus be protected from damage by trucks"
and "eye wash stations be provided within 25 feet" etc.).. I'll will tell you
the majority of the failed / scummed out battery banks I've dealt with have
been from poor ventilation, poor maintenance or defective / improperly
designed or installed battery boxes.. If I can, one of the first remedy's I
apply is to drill several large holes (and staple some kind of critter
proofing over the holes from the inside). -or- if I can gracefully, I'll
remove the sides altogether -- as long as the electrical connections are
protected. also if I can, I try to find a way to route exhaust gases so they
vent naturally -- so they don't rely solely on a vent fan... like maybe run 2"
PVC up thru the roof -- inside the envelope of the house. at least try to make
sure the fan is not competing with the furnace or exhaust systems... (like
insure there's an adequate <SPAN>intake air<SPAN
id=GD__CURSOR> </SPAN></SPAN>supply for the whole house)... as for
protecting batteries from fluctuating temps.. the planet
<SPAN><SPAN><SPAN>(some three feet down anyway)</SPAN><SPAN
id=GD__CURSOR></SPAN></SPAN><SPAN id=GD__CURSOR> </SPAN></SPAN>stays just
over 48 degrees.. at least in these par<SPAN><SPAN
id=GD__CURSOR></SPAN></SPAN>ts.. Just saying.. db<BR></DIV>
<DIV><BR>Dan Brown<BR>Foxfire Energy Corp.<BR>Renewable Energy
Systems<BR>(802)-483-2564<BR><A
href="http://www.Foxfire-Energy.com">www.Foxfire-Energy.com</A><BR>NABCEP
#092907-44</DIV>
<DIV><BR></DIV></SPAN>
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