Darryl, Lead acid battery typically recommended bulk charge is 10-15% of C20 for the flooded lead acid and 20 -25% of C20 for the sealed valve regulated lead acid. Depending the application and the environment, these rates could be optimized, on a case by case basis. As the battery voltage raise to the absorption voltage (regulation voltage), the current automatically tappers due to the PWM or MPPT regulation. Off-grid standalone PV systems optimum designs feature 5-days autonomy at 80% DOD at the worst month-average low temperature. Off-grid PV-genset hybrids optimum designs typically feature 2 to 3 days autonomy at 80% DOD same conditions. The purpose of the large battery bank is to take the best advantage of the solar energy when it is available to store Ah in the battery for a desired power supply system power availability level. So the maximum current available from the PV array, after powering the load, is not wasted and sent into the battery during bulk charge and then tapered in as the voltage raise.
Lithium-ion batteries charge mode have certain benefits in some well-defined applications requiring fast charge with the requirement of a BMS. John From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Darryl Thayer Sent: Wednesday, August 24, 2011 10:44 AM To: RE-wrenches Subject: Re: [RE-wrenches] Lithium Ion Phosphate for grid back up One of the advantages of LiFeP is the fast rechange rate. I have found that fast recharge is very hard on LA batteries, if they are recharged faster they fail sooner. Perhaps Jamie or others could answer is there something that can be recharged fast? Capasitors are almost impossible to work with. Lead carbon? Ni Magnisum Cobalt? From: Jeff Oldham <starpowe...@juno.com> To: re-wrenches@lists.re-wrenches.org Sent: Tuesday, August 23, 2011 5:31 PM Subject: Re: [RE-wrenches] Lithium Ion Phosphate for grid back up I 2nd what Ray Waters is saying. Much too soon, BMS will be an insane challenge, we rarely care about weight and footprint like the EV's do. Returning defective cells to China IF they accept responsibility for the failure - I don't think so!! Sex appeal is overwhelming good judgement, one of the curses of our industry. >From the Solar, Wind and Hydro powered office of Jeff Oldham/Regenerative >SOLutions ____________________________________________________________ Penny Stock Jumping 3000% Sign up to the #1 voted penny stock newsletter for free today! <http://thirdpartyoffers.juno.com/TGL3132/4e542a7bb4c77837e37st04vuc>AwesomePennyStocks.com<http://thirdpartyoffers.juno.com/TGL3132/4e542a7bb4c77837e37st04vuc> _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org<mailto:RE-wrenches@lists.re-wrenches.org> Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm<http://www.re-wrenches.org/etiquette.htm> Check out participant bios: www.members.re-wrenches.org<http://www.members.re-wrenches.org> This e-mail message and any attachments that accompany it may contain information that is confidential, privileged, or protected from disclosure. It is intended solely for the use of the individual(s) to whom it was intended to be addressed. If you have received this e-mail by mistake, or you are not the intended recipient, any reading, disclosure, copying or other use of this communication is strictly prohibited. If you have received this communication in error, please immediately advise the sender at their phone number listed above, or by electronic mail, and also permanently delete the original and all copies of this e-mail and any attachments from all locations. Thank you.
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