Hi All, My 2 cents.
I’ve recently had to do some research for someone who had 16 Full River 400/6v melt down. ( 48v bank, 2-3 yrs old). Both banks, all 16 melted. In talking with a battery company expert, what I was given is the following: AGM if not charged correctly, especially if they are allowed to sulfate ( under charge), and then charged heavily during hot conditions can melt down. When flooded get sulfated they won’t accept a large charge, current is low. AGM appear to have the opposite reaction which is that they create high resistance but accept current creating lots of heat. They can’t vent the heat ( no caps and if there isn’t enough room around them they can’t expel the heat either. In a sense if they can melt together, they are too close together ) and if there is external heat to contribute then once they get to 40-50C internal they can melt down. I mentioned in a previous post that Full River has an EQ type cycle for batteries that are showing lowered capacity which is a form of sulfation and this EQ is to try and prevent this exact situation. As to MK, I don’t use them as they have very low cycle life. Those MK 8D AGM are around 700 cycles to 50%, vs Full River or Rolls AGM at around 1300 cycles to 50%. VRLA are a pretty tricky compared to flooded. jay peltz power > On Nov 29, 2018, at 8:33 AM, Starlight Solar Power Systems > <[email protected]> wrote: > > Let me confirm what William has shared about Deka/MK 8D AGM batteries; they > have a very high failure rate. We saw over 40% fail within 2-3 years of > installation. Deka would not own up to the problem and offered no > compensation. > > Fullriver has been the finest AGM we have ever sold. All DC models are > excellent. We especially like the 2 volt L-16’s for high capacity systems. We > had one failure, and I know of one other, where L16 batteries went into > thermal runaway. The cases welded together. After fully testing the power > system that we designed and installed, we found no problem. Fullriver would > not offer any help or replacement. > > Our installations are 100% battery based. When I do see failures I have many > other identical power systems to compare with (in the thousands, we do 5-8 > per week) and this helps me make sound judgements about our findings. > > Larry Crutcher > > 3 year old Deka 8D > <Deka 8D AGM failure_ (2).jpeg> > > 1.5 year old Fullriver L-16 > <IMG_0629 (1).jpeg> > > > On Nov 28, 2018, at 11:43 PM, William Miller <[email protected] > <mailto:[email protected]>> wrote: > > Allan: > > We have had poor luck with the 8D AGM batteries (MK/Deka). Many of them have > had short life spans along with swelling, heating and even exploding. Your > point about the inefficient footprint is right on. > > I have minimal experience with Full River. I have seen a set fail, but heck, > anyone can do that in a hurry. > > When footprint is an issue, we have gone to racked AGMs, like the Deka Unigy. > Now to get higher voltages might require custom racking, but the cells come > in lots of sizes and shapes, physically and in capacity. It may be worth > checking into the size of a 400 AH Unigy cell and see how they rack up. I > don’t have but a smattering of drawings for the models we have purchased, but > my cursory look indicates you won’t save on volume or dollars, but you may > gain a smaller footprint with some Unigy racks in series. > > William > > <image002.jpg> > Lic 773985 > millersolar.com <http://www.millersolar.com/> > 805-438-5600 > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org >
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