Not sure about SMA but XW and Radian would definatley change the absorb time. Having the lower AH number would be a longer absorb time on an XW. That would be a good thing as it would get the full programmed absorb instead of 2% of the programmed AH. It is a whichever comes first algorithm.
Dave Angelini Offgrid Solar "we go where powerlines don't" http://members.sti.net/offgridsolar/ [1] e-mail [email protected] [2] text 209 813 0060 On Wed, 14 Jul 2021 13:42:23 -0700, Jeff Clearwater wrote: Hey Jay, Yes the Sunny island Master of this Quad SI AC-coupled off-grid system has been giving automatic Eq and Full charge charges perodically as appropriate to this 48 V EnergyCell RE2700 pack. We are getting whole pack volt drops way before we should at 600 well- maintained cycles. When we do whole pack testing - when the voltage drops off there are 5 of the 24 cells lagging - their voltage drops faster than the rest - but they operate well between 50%-100% - all busbars have been triple checked for corrosion and tourque. So it looks like they just aged prematurely - so I'm in the process of collating data from EnnexOS to get exact numbers on how they've been treated. But even with a few hard cycles they should held up better than they have. So perhaps a warranty claim - I've gone through charge settings with SMA etc. I did have the AHrs programmed slightly below rated AHrs due to confusion of whether the SI uses the 20 hr or 10 hr rate (in Europe they use 10 but apparently - unbeknowst to me - the US SI uses the 20 Hr - I swear SMA tech support years ago told me 10 hours) but now they are claiming that might be the culprit - I have a hard time believing that setting the Ahour rating in the SI to 2100 instead of 2288 as rated would lead to pack failure - but they are claiming that could have contributed. Thoughts? Best, Jeff Jay [3] July 14, 2021 at 1:15 PM Hi Jeff If it's the energy cell xlc from Outback then it shows an eq requirement. If not that battery, most industrial quality VRLA I've seen have a eq requirement, conditioning charge or something similar. And the lowering of capacity is common from experience. Question What equipment/brand is charging it? Jay Peltz power Jeff Clearwater [4] July 14, 2021 at 11:32 AM Thanks Dave - yes I've done whole pack load testing. The deal with this pack though is that it is so remote and the expense of "just replace the pack" in terms of shipping and labor is extreme - (tiny Bahaman island with only regular small boat access} And if it was toward the end of the pack's life anyway I'd not mess around - but with only 600 well documented cylces on a $25K pack - and with probably half that again in shipping and labor to replace - I'm needing to carefully document the lagging cells for either a warranty claim or at least to make good decisions going forward. It's easy to access the cells as this is an EnergyCell AGM stack with easily accessible terminals and removable terminal bars. If we replace we'd go LFP - on the order of 100 KWHrs. So no small decision for the customer - so worth the testing. Thanks! Jeff Clearwater Village Power Design www.villagepowerdesign.com [5] _______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org [6] List Address: [email protected] [7] Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org [8] There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/[email protected]/ [9] http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org [10] List rules & etiquette: http://www.re-wrenches.org/etiquette.htm [11] Check out or update participant bios: http://www.members.re-wrenches.org [12] Links: ------ [1] http://members.sti.net/offgridsolar/ [2] mailto:[email protected] [3] mailto:[email protected] [4] mailto:[email protected] [5] http://www.villagepowerdesign.com [6] http://re-wrenches.org [7] mailto:[email protected] [8] http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org [9] https://www.mail-archive.com/[email protected]/ [10] http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org [11] http://www.re-wrenches.org/etiquette.htm [12] http://www.members.re-wrenches.org
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