Bill, I haven't tested temperature gradients, so in that respect I can't answer your question. Also, my post was a cautionary note to Kirpal to evaluate the temperature effects in deciding whether to stack flooded batteries. But he noted "big banks" and "7000 pounds", both of which suggest tall flooded LA batteries - typically 26" tall. Given that some degree of visual access into the cells from above is necessary, we're talking at least about 6' from floor to top of upper row. This is more than the 35" or so of the Outback cabinet, and likely to result in stratification nearly commensurate with the floor-to-ceiling differences in the battery room.
It was Jeff at Direct Power who wisely cautioned me against this years ago when I wanted to stack Concordes floor to ceiling in a confined space. We ended up using the Outback cabinets that you mention, keeping the total height below 35". Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.PositiveEnergySolar.com <http://www.positiveenergysolar.com/> From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Loesch Hi Allan, et al, Just what amount of temperature difference (and corresponding SOC difference) are we talking about? In previous incarnations, Outback produced an attractive albeit very labor intensive unassembled battery cabinet which, if my old memory is correct, this optionally _enclosed_ battery cabinet could enclose three(?) 8D batteries in a ~four foot high box with an ~ 8D footprint. If this isn't the near ultimate of an"indoor space" with corresponding temperature stratification please advise of a more confined space application. Wouldn't the current Outback stacked Group 27 cabinet be subject to the same physics? Thanks for your superior use of the thinking cap and literally thinking "outside the box". Bill Loesch Solar 1 - Saint Louis Solar 314 631 1094 ----- Original Message ----- From: Kirpal Khalsa <mailto:solarwo...@gmail.com> To: RE-wrenches <mailto:re-wrenches@lists.re-wrenches.org> Sent: Monday, October 19, 2009 7:05 PM Subject: Re: [RE-wrenches] Battery Racks Allan......very good point...I had not thunk that far......It will probably be a good difference in temp. too.....I am not quite sure how we would address that as the system will only have one charging source and 2 strings of batteries.....one on the top shelf and one on the bottom....???? Any ideas? I my initial inclination would be to lean towards putting the temp sensor on the top string as over heating of the battery bank due to over charging is probably a bigger concern than being very cold as this is in a residential garage with out much insulation in relatively mild wintered Oregon.... Thanks to all for their ideas and recommendations....this list and its members are definitely a priceless resource.....I would gladly share my chantrelle mushroom loot i just pulled out of the forest with you all were you here right now! Cheers.... -- Sunny Regards, Kirpal Khalsa On Mon, Oct 19, 2009 at 1:12 PM, Allan Sindelar <al...@positiveenergysolar.com> wrote: Kirpal, Keep in mind variations in upper- and lower-bank temperatures from ambient heat stratification if the batteries are in an indoor space. This affects relative SOC among strings, affecting string life. Sent: Monday, October 19, 2009 1:47 PM Hi All.....anyone have any experience with battery racking systems for big banks of flooded lead acid batteries? Typically we don't like to stack flooded batteries but we may not have space for as big of a bank as we need if we don't stack......Any one know of a company that engineers racks that are seismically sound, have the ability to have spill containment all while maintaining some accessibility? I know DPW makes battery racks but looking at their web site they are typically smaller than what we need..... We need to support roughly 7000lbs.....and are exploring if this is even doable.... Cheers and thanks! -- Sunny Regards, Kirpal Khalsa
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