Hi Jon, my take is the absorb is way too short, the array is way too small, The solar period is over before the batteries are charged. I would set absorb at 28.8 Volts, 6 hrs, because the winter days are short. I do not know how to set charge max amps with paralleled controllers. Then set back to normal for after equinox.
On Tue, Feb 18, 2020 at 10:37 PM Jon Siegenthaler < [email protected]> wrote: > Hey Wrenches, > > I just did a site visit for a client who's had a few iterations of PV > installed. The main reason for the call was that the battery bank would > never charge to 100%SOC but rather appear to charge to 100%SOC and actually > hover around 70%SOC. At the end of the day the client would top it off > with the generator for 30-60min. This has been happening since October, I > just got the call the other day. > > The site is less than code compliant to say the least and the programming > of the 3 charge controllers were not equal. > > Array 1 South Facing 4-Canadian 250w (one string) > Flexmax 80 > Absorb 29.3V 6hrs > Float 27.3 > End Amps 10A > Rebulk 25V > > Array 2 South Facing 6-205w 2-195w (one string) > Flexmax 60 > Absorb 29.3V 6hrs > Float 27.3 > End Amps 10A > Rebulk 25.6V > > Array 3 North Facing 8-295w Renosola (4 strings) > Flexmax 80 > Absorb 29.4 1hr > Float 27.3 > End Amps 0 > Rebulk 24 > > 20-Trojan Reliant L16 12V (5 parallel to a bus) purchased the end of 2017 > > Apart from the not so great design to say it lightly, the bank is > consistently showing a stepping voltage of about 70%SOC up to 100%SOC from > negative to positive. I changed the charge controllers to an equal > absorption voltage and time (28.8V and 4hrs) to try and slowly bring up the > lagging side of the bank. I was cautious not to raise them all to 29.4 at > 4+hrs because I don't know their history and didn't want to cook them > further if they are indeed headed that way. At the time of inspection the > batteries were about 84F and the thermal camera showed no variations or hot > spots. > > I asked the owner to report back if it gets better, worse, or the same. He > reported back and said that the total kWh production daily is gradually > going down over these past few days. Any suggestions on how to bring this > bank back to 100%SOC would be appreciated. > > Jon Siegenthaler > _______________________________________________ > 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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