Jeff, I agree with you about most arrays being too small to sufficiently overcome internal resistance and get voltage high enough to effectively equalize. I won't advise either (early or late) approach to running the generator. Most homeowners won't understand the variables and subtlety involved in determining when and how to EQ. Rather, I will often advise that the homeowner considers the gennie as the only tool to pump enough amps into the batteries. I'll suggest that equalization be done during the day when the sun is shining, and that both array and generator are used together. This maximizes the C/rate and has the greatest likelihood of reaching full EQ voltage and holding it there. Flooded batteries can handle up to around a C/7 rate if in good condition. Allan at Positive Energy
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jeff Yago Sent: Thursday, October 23, 2008 2:55 PM To: RE-wrenches Subject: Re: [RE-wrenches] Best Off-Grid Equalize Charging Method I know this has come up before but wanted to see if anything new available. Unlike on-grid battery-based systems, off-grid systems require a different equalize charging strategy to reduce generator run-time and save fuel. The problem arises when you have a large battery bank and a not so large solar array. You can first run the generator early in the morning at a high bulk rate to shove as much charge into the battery as possible, then take over charging with the solar charge controller set for equalize charge and hope you have enough sun-hours and current to take the generator-charged batteries past their normal voltage and start gassing, OR, You can do the reverse and solar charge all day and then at the end of the day use the generator with the inverter set for equalize charge and continue charging while hoping this will not require too many hours of fuel usage. Of course the size of the solar array verses the size of the battery bank may favor one method over the other, but are there any actual tests or studies that make one method always the better choice? I have found that small arrays have a real hard problem ever getting a large battery fully charged, let alone provide an equalize voltage for several hours, yet I have also found most inverters supplied by a generator tend to back-off the charging current as soon as the battery nears a fully charged state then tries to stop the generator. I also have found that some deep-cycle batteries sold for solar applications require charging voltages and re-charging times that are almost impossible to achieve unless you have grid power available. Any documented testing out there? Thanks, Jeff Yago _____________________________________________________________ Netscape. Just the Net You Need. _______________________________________________ List sponsored by Home Power magazine List Address: 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 Check out participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Home Power magazine List Address: 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 Check out participant bios: www.members.re-wrenches.org
