Larry:
Are the problems you have encountered with the Deka/MK 12V AGMs also an
issue with the 8AGC2 6V AGM? Are the problems you're seeing with climate
controlled batteries, or with outside cabinet mounted batteries?
I have an application having I believe heat related failures with one
48V string of outside cabinet 8AGC2 batteries in an off-grid battery
based inverter/charger with generator charging (6kw LP generator).
Temperature compensated bulk charging of 60A DC is delivered to the bank
(0.3 x C20).
Gary
On 8/3/2012 5:03 PM, Larry Crutcher, Starlight Solar Power Systems wrote:
Vince,
I know of no such "vulnerability". In fact, an AGM can provide much
more instant current than any flooded battery. Concorde (Lifeline,
SunXtender, etc.) and Fullriver AGM's are very robust designs. On the
other hand, Deka AGM's, specifically the 12 volt 8A8D, are not to be
trusted at all. We have stopped selling all Deka/MK AGM's due to very
high failure rate.
One other point to consider, having 5 parallel strings of 12 volt
batteries is generally asking for short battery life, especially with
an AGM since you can not check the SG to be sure all are charged
fully. Cells do not charge at the same rate and having parallel paths
for current will leave some cells deficit charged. Having many
parallel strings exacerbate this issue. If you do upgrade the bank,
opt for lower voltage, higher capacity batteries.
Larry Crutcher
Starlight Solar Power Systems
(928) 342-9103
_
_
Just a word of caution on the AGM batteries. AGM's do have some
vulnerabilities compared to deep cycle wet filled batteries. We had a
bank of 20, 8A8D running a Buddhist Retreat compound and were unable
to convince our clients that there were limitations to the amount of
power that they could run at one time. They managed to overheat and
destroy the whole bank of batteries we think by using too much power
during a retreat camp. People had brought there own appliances to use
at the camp and we still don't know what the total load was on the 4,
Outback VFX 3648 inverters. I'm guessing it was up there close to the
14.4 kW limit of the Outback inverters. We also petitioned our client
for a larger battery bank but they didn't think they would ever need
that much power.
--
--
*Vince McClellan
Energy Design
_www.solarenergydesign.com <http://www.solarenergydesign.com/>_
p: 541.485.8122; f: 541.338.3168*
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
