Have u considered, or is it possible, to set the batteries several ft. into the earth? 50 or so year round. Works for livestock water, earth sheltered houses, caves.....
On Feb 27, 2018 10:29 AM, "Starlight Solar Power Systems" < [email protected]> wrote: > Hi Drake, > > I agree. Li-ion batteries, like lead batteries, should always have a human > overseer. This is a difficult reality to convey in our set-it-forget it, > automated world. > > One function of a Li-ion battery EMS or BMS is to prevent over discharge. > Once any battery cell reaches the lower limit, the battery will turn off. > For many systems, once charge current is again detected, the battery will > turn on. Some will not and require a user to turn the battery back on. You > can also install an external LVD device to stop power use at a higher SoC. > > As wrenches, its our responsibility to know our product and educate the > customer. Too often, this does not happen. > > Larry Crutcher > Starlight Solar Power Systems > > > > > > > On Feb 27, 2018, at 7:11 AM, [email protected] wrote: > > Snow on the array could be a very big problem with the heater load, > inverter idle current and anything else that might be left on. Extended > periods of heavy clouds can reduce power generation to be less than > system's internal losses. It seems like a pretty big gamble to leave an > expensive battery bank unattended, that can not go below freezing, and is > dependent on array power to prevent freezing. > > If AGMs survive in this application, it might be better to stay with this > technology. > > > > ----- Original Message ----- > From: > [email protected] "RE-wrenches" <[email protected]> > > To: > "RE-wrenches" <[email protected]> > Cc: > > Sent: > Mon, 26 Feb 2018 10:36:29 -0800 (PST) > Subject: > Re: [RE-wrenches] heating a lithium battery bank > > > Hello Daniel, > > I will give this some thought. What lithium make? The ones I have looked > at log the temperature for warranty so that might negate the value a bit. > The high temp is just as bad in your case here. > > Since this has been working well I am assuming snow on the panels is not > an issue? > > Building a battery box that was cooled (small fan) from conditioned space > is what I have done. The wall between the garage and living space is > perfect. This won't help when the house is cold (unattended) much. It > won't help if the house is allowed to get hot either. > > Some of the Lion batteries are actually listed for living space. The LG > is. I don't do that with mine though. Hmmm > > Dave Angelini Offgrid Solar > "we go where powerlines don't" > http://members.sti.net/offgridsolar/ > e-mail [email protected] > text 209 813 0060 <(209)%20813-0060> > > > Hello Wrenches, here is a fun one for you all. > > > > > > > > The client you all helped me with earlier this year is now considering > > changing out their AGM off grid bank with a lithium battery bank before > > the > > next winter. I looked into this, as we have been eying the various > lithium > > options for 2+yrs now, but not bit the bullet and really designed a bank > > into a system. > > > > > > > > The main issue I am trying to consider is this. The cabin is not occupied > > during most of the winter, and the batteries are in the unconditioned, > but > > attached, garage. They drain the plumbing system and shut off all > breakers > > except the ones that power the internet, chest freezer, and security > > system. > > As such, the battery bank has routinely gotten below freezing, sometimes > > staying there for 1-2 weeks. This is not an issue with AGM's, within > > reason. > > The battery bank has never gotten below 20F over the last 2 winters, > where > > the site has seen below zero temps for brief periods. But the AGMs likely > > produce more heat during a charge than lithium's, and they have > > significantly more thermal mass to ride through the really cold nights. > > > > > > > > Lithium batteries, to the best of my knowledge, can be below freezing > > during > > storage. But to safely charge, they must be above 32F. So the thought was > > to > > provide an insulated battery box, and design in some small heating system > > that is set to 40-45F. The first thought was a low power fiberglass > > heating > > pad like is sometimes used for livestock to give them a slightly warmed > > place to lay down. Then tie that to a thermostat with a sensor on the > > battery bank. I would of course need to try to account for the extra load > > in > > the battery bank sizing. They array is more than is needed right now so I > > do > > not worry about it's ability to compensate when the sun is shining. > > > > > > > > In theory this could be ok, but I worry about the summer. Will the > > insulated > > enclosure cause the opposite issue during the summer, the batteries > > getting > > too hot? I have seen the AGM bank go to 110F at one point in Aug 2016. > But > > with the lower internal resistance of the lithium's, maybe this is less > > likely to be an issue. Do any of you wrenches have any experience with > > this > > unconditioned setup? > > > > > > > > With Regards, > > > > > > > > Daniel Young, > > > > NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90 > > > > _______________________________________________ > > 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]. > org/maillist.html > > > > List rules & etiquette: > > www.re-wrenches.org/etiquette.htm > > > > Check out or update participant bios: > > www.members.re-wrenches.org > > > > > > > Dave Angelini Offgrid Solar > "we go where powerlines don't" > http://members.sti.net/offgridsolar/ > e-mail [email protected] > text 209 813 0060 <(209)%20813-0060> > > _______________________________________________ > 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]. > org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > _______________________________________________ > 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]. > org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > > _______________________________________________ > 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]. > org/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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