HI Ray, We could still use them now and for legacy systems. I can only think it could be a big help in saving battery banks of all types.
jay peltz power On Sep 17, 2014, at 6:32 AM, Ray Walters wrote: > I think if we started over fresh with our lead acid battery system designs, > we would find we should have the same Battery management system requirements > that you have mentioned. Those are all problems that plague lead acid as > well. > R.Ray Walters > CTO, Solarray, Inc > Nabcep Certified PV Installer, > Licensed Master Electrician > Solar Design Engineer > 303 505-8760 > On 9/15/2014 8:08 PM, jarmo.venalai...@schneider-electric.com wrote: >> Hi: >> >> We've done some testing and operation of Lion battery banks in the 10 kWh >> range with our inverter chargers and so far the most important findings are: >> >> 1. The battery pack must have its own battery management system to: >> a. regulate the individual cell voltages during charge and discharge >> b. balance the cell voltages during charge and discharge >> c. adjust cell charging voltages due to temperature variations >> d. not provide a continuous float voltage to the battery bank >> d. provide a built in safety cutoff disconnect, which turns off the current >> if for any reason either the charge or discharge current is too high. >> >> A series string of Lion cells, without the battery management system >> functions above is very likely to result in damaged cells or worse. The >> most likely mechanism which ultimately causes damage is individual cell >> temperature or cell to cell voltage imbalance. >> >> 2. The inverter system must be designed so that the inverter never draws so >> much current that the current limit circuit in the battery bank is >> triggered. >> >> 3. It may be necessary to adjust the current limit circuit as they typically >> respond within milli-seconds and may be triggered on simple power up as the >> inverter cap bank charges up. >> >> 4. When working with Lion, the inverter/charger should be configured so that >> it is a simple current limited voltage source when in charge mode. The >> built in battery management system should take care of the required charge >> cycle operation. >> >> 5. Whether the pack is LiFePO4, Lion polymer or other does not appear to be >> as important as a having a reputable brand and more importantly a well >> designed built in battery management system. >> >> The short version is that lead acid cells are amazingly forgiving with >> regards charging and discharging voltages, currents and temperatures. Lion >> cells on the other hand are amazingly sensitive and going out of bounds on >> any of these can and will cause irreparable damage. >> >> Given the sensitivity, it doesn't make sense to take on responsibility for >> Lion battery management. >> >> Management of that sensitivity and responsibility is best left to the >> battery bank manufacturer. >> >> JARMO >> _____________________________________________________________________________________ >> >> >> Jarmo Venalainen | Schneider Electric | Solar Business | CANADA | >> Training & Development Specialist - Senior >> Phone: +604-422-2528 | Fax: +604-420-1591 | Mobile: +604-505-0291 >> Email: jarmo.venalai...@schneider-electric.com | Site: www.SEsolar.com | >> Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 >> >> <Mail Attachment.jpeg> >> *** Please consider the environment before printing this e-mail >> >> >> >> From: "William Miller" <will...@millersolar.com> >> To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org>, >> Date: 09/15/2014 04:27 PM >> Subject: [RE-wrenches] LiFePo4 >> Sent by: "RE-wrenches" <re-wrenches-boun...@lists.re-wrenches.org> >> >> >> >> Wrenches: >> >> Does anyone have any experience with Lithium Ferrous Phosphate cells? What >> are your experiences? I am looking at an installation tomorrow and would >> like some input. >> >> Thanks in advance. >> >> William Miller >> >> <Mail Attachment.jpeg> >> Lic 773985 >> millersolar.com >> 805-438-5600 >> >> >> ______________________________________________________________________ >> This email has been scanned by the Symantec Email Security.cloud service. >> _____________________________________________________________________________________________________________________ >> 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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