<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Ron,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>This reply a little late since I have been off line a few days. I mentioned in a similar thread last year that I had an off grid home client I designed and installed in Idaho back in 1998 that had a Kohler 8.5 kw generator, a Trace 4024 inverter, two separate solar arrays and Outback charge controllers, and 16 Trojan “L-16” batteries. This system worked flawlessly for 7 years and only required the generator a few hours per month, then it was time to change the batteries. I replaced the Trojans with the same size battery made by Surrette and everything went to crap. They had to run the generator hours and hours to get them past an 80% charge and we had lots of problems with overloading the generator even though we did not make any program changes and used the same generator. The generator was replaced 2 years later but this system never worked like it did before the battery replacement.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>When researching all this at that time I had talked with Surrette, Trojan, and anyone else that might help and this is what I found out. Of course there are just my opinions based on these conversations, but it is my understanding that Surrette is a much longer life battery with much less water loss when comparing apples and apples, and I was told this was due to a different lead composition that Surrette uses than any other battery manufacturer. However, this difference requires a much longer absorption/taper off charge process or you will never get it past 80% charged. This of course is almost impossible to achieve with a generator or undersized solar array, and you really need a grid connection to fully charge these things. No doubt these would be great in some standby grid connected system but I no longer use them in off grid. This was also at a time when battery manufacturers were just discovering solar so maybe battery designs have changed. Again, I think Surrette is a good company and makes a great battery, but just not sure you can fully recharge them with a mid-sized generator.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I also do not like using parallel battery layouts as its hard to keep one string from pulling down the other strings when there is a low performance cell so you might do a cell by cell check.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Good Luck,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Jeff Yago<o:p></o:p></p><p class=MsoNormal>DTI Solar Inc.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------<o:p></o:p></p><p class=MsoNormal>This is not what I expected after a lengthy EQ. I'm getting them to do another one tomorrow after a discharge cycle and charge but I'm really beginning to think we have something else going on here, something electrical, not chemical. The rapid voltage drop is puzzling. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>To review, it's an Outback 3524 on an Epanel, Whisper 100 & controller, 6 4KS 25 Surrette batteries in 24v configuration - 4.5 years old, .7kw solar. I know the charging end is undersized but they have been compensating with the generator and they get lots of wind in the fall, winter, spring.<o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p></div></body></html>