Yeah, it's my understanding that the BMS systems on each parallel battery deals with/prevents any imbalance.
As for 48V, I have been working with some that are 51V nominal and I know there are some 60V solutions out there, so it's not so cut and dry to use amp-hours. That's why I like talk in kWh to standardize. I am taking the DoD into account when discussing my needs. I would probably need a battery almost double the size in a lead acid chemistry! On Tue, Jul 23, 2019 at 8:59 PM Jerry Shafer <jerrysgarag...@gmail.com> wrote: > William > I have a few blue ion installs that was used for testing. I used eguage to > monitor all DC in and out of each stack of 16k with no issues. The BMU > manages everything and can be chained to each other to reduce or even > prevent that issue. I have seen Blue Ions original stacks greater then 100k > with years in the field, so with that cross bleed should be not a problem. > Jerry > > On Tue, Jul 23, 2019, 4:59 PM William Miller <will...@millersolar.com> > wrote: > >> Friends: >> >> >> >> I am a complete newbie to any lithium technologies, so please forgive >> some newbie questions: >> >> >> >> I am used to working in amp hours. If we are looking for a battery bank >> in the range of 100 kWh, this converts to about 2,083 amp/hours at 48 VDC. >> Is my arithmetic correct? An on-line calculator seems to confirm this. >> >> >> >> The biggest Blue Ion 2 battery is 16 kwh. At 48 VDC this is about 333 >> amp/hours. This is like an L16. To get 100 kwh you would need to parallel >> 6 strings of the 16 kWh batteries. I would never do this with L-16s. Is >> anyone worried about circulating currents in this type of installation? Is >> there technology to prevent one string from cannibalizing another? >> >> >> >> Here is another, more academic question below: >> >> >> >> In case I am using a term I made up (which is often the case), I define >> circulating currents as currents flowing between parallel strings without >> any outside influence. For example, if you disconnected all charging and >> loads from an array with two parallel strings, unless the strings were >> absolutely identical in electrical characteristics, there would be some >> current flowing between the two strings. In my opinion this is the >> Achilles heel in parallel strings. Also my opinions: 2. The more strings >> you have the more chance there will be debilitating circulating currents. >> 3. The older the batteries, the more the electrical characteristics will >> vary and the more likely you will get higher circulating currents. >> >> >> >> It is my theory that if you can measure the circulating currents, or the >> difference between parallel battery strings at any point in the operation >> of same, you can get a read on the health of the strings. The more the >> operating or idle currents diverge, the more one string will discharge the >> other string. I guess this is some part of a battery management system. I >> am guessing for the Blue Ion 2 to work in 6 parallel strings, they need to >> monitor and control this difference in currents. >> >> >> >> We just installed a flooded battery array (2 strings of 4 Deka M6100-33 >> batteries). My plan is to retrofit the installation with a 1000A/100mv >> shunt in the negative leads of both strings. With a DVM I can spot check >> the circulating currents to learn about the battery health. In fact I have >> a remote monitoring system >> <https://millersolar.com/MillerSolar/Portfolio/Commercial/Cal_Trans/Remote/Remote_Control.html> >> with some spare ports that can log these values. Might be an interesting >> experiment. >> >> >> >> I appreciate any input on the viability of the Blue Ion 2 or other small >> battery systems in multi-string installations. My customers are asking for >> new technology, but I instinctively avoid parallel battery strings. >> >> >> >> William Miller >> >> >> >> >> >> >> >> Miller Solar >> >> 17395 Oak Road, Atascadero, CA 93422 >> >> 805-438-5600 >> >> www.millersolar.com >> >> CA Lic. 773985 >> >> >> >> Quote of the month: “As they age, batteries transition from energy >> >> storage devices to energy consuming devices.“ W. Miller >> >> >> >> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On >> Behalf Of *Lou Russo >> *Sent:* Saturday, July 20, 2019 1:50 PM >> *To:* RE-wrenches >> *Subject:* Re: [RE-wrenches] Large Off-Grid Residential System >> >> >> >> Blue Ion 2.0 with Outback or SMA. Works every time. >> >> Blue Planet's tech support is great, the warranty is even better. >> >> >> >> Aloha, >> >> >> >> Lou Russo >> >> l...@spreesolarsystems.com >> >> 808 345 6762 >> >> Spree Solar Systems LLC >> >> CT-34322 >> >> >> >> >> >> >> >> On Sat, Jul 20, 2019 at 10:36 AM Jay <jay.pe...@gmail.com> wrote: >> >> Hi Marco, >> >> >> >> Is the max surge 7kw, which is what is listed on line? >> >> >> >> Jay >> >> Peltz Power >> >> >> On Jul 19, 2019, at 3:10 PM, Marco Mangelsdorf <ma...@pvthawaii.com> >> wrote: >> >> Seven to eight Tesla Powerwalls will get you that assuming that the >> service entrance is no bigger than 200A. >> >> >> >> marco >> >> On Friday, July 19, 2019, Jason Szumlanski < >> ja...@floridasolardesigngroup.com> wrote: >> >> What are current popular options for battery based systems in the 100kWh >> range? Preferably Lithium. >> >> >> >> Also, what inverter pairing is suggested with total stacked capacity of >> 36kW, 120/240V? >> >> >> >> This is slightly larger than some of the systems I have worked with >> recently. I'm a bit out of the loop, particularly on the battery side of >> things. >> >> >> >> Jason Szumlanski >> >> Florida Solar Design Group >> >> >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.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: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.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: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.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: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.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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