Hi gang This is a little off topic but covers battery charging in general. In an industrial charger situation you don't have the time to wait for the sun to charge the battery bank. You work the hell out of them for 8 or 16 hours, charge them overnight, then you do it again! The vast majority are just big "taper" type chargers, with minimal controls. As solar installers we would love to have all our customers buy enough solar to charge daily in the available amount of sunlight, wouldn't we? I have seen forklift batteries taken to the service shop from an industrial freezer and they had to wait for 3 days for the battery to thaw out before they could service them. The industrial chargers that I deal with are primarily 3 phase 480 or 640 volts. The last time that I replaced one, I asked about temp compensation on the new unit and was amazed when I was told no one did that. It's just a big dumb battery after all... There are some chargers out there that I can best describe as a "high frequency" charger. They are small wall mounted units that have a sound that you will not mistake for anything else once you've heard it. They seem to charge in bursts of varying length and help keep the battery temp down that way. The battery shops I know hate them, the only way to service them is to bring a truck full of circuit boards and replace them till it charges correctly!
We mostly use Magnum inverters now as they have a better charger than Outback and most of the jobs are off grid. Both are good units as we are all well aware, but the Magnum charger does more charging with less AC power input. The 4024 does something 105 amps v/s 70 amps DC as a charger and I think the AC draw is still less. Magnum's weak spot, still no reverse power input protection to save some dummy who happens to reverse the in and out hot leads! I hate days like that. The short answer would have been that we treat our batteries better, charge quality wise on a bad day, than most industrial sets get treated on a good day! Needless to say that would not include owner abuse or neglect, we all see that. Later, Bob -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of R Ray Walters Sent: Thursday, March 25, 2010 5:59 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV excellent battery charger On Mar 25, 2010, at 5:55 AM, Warren Lauzon wrote: > Actually, PV is not a particularly excellent battery charger, What is better than a properly sized array with the latest controllers? > > Everything else mentioned can be done by any decent AC battery charger. True, but at great expense. The traditional AC chargers like the ones made by Lester are industry standards, and are archaic in comparison. Now chargers that come with say an Outback Inverter, that was installed as part of a solar system, do have everything as you mentioned except I'm not sure about the PWM. We'd need to hear from Chris Frietas or some other Manu rep to further explain the charge regulation on the Outback inverters, and whether it uses PWM. Outside of the solar industry, batteries are not treated near as well. Ray > > >> My understanding is that the voltage, in excess of battery voltage, from >> the array, represents energy that is dissipated as heat in the batteries. >> This extra voltage, multiplied by the amperage is wattage. This extra >> power can produce more amps at a reduced voltage. It is amperage that >> charges the battery. >> >> Thanks, >> >> Drake >> >>> MPPT doesn't really do that much for the battery, it just makes the PV >>> modules more effective. >>> The real magic is: >>> A) the 3 stage charging (compared to traditional single stage AC chargers) >>> B) Temperature compensation >>> C) PWM that helps pulse off sulfation >>> D) Slower charge rates let batteries charge more fully without damage from >>> overheating. >>> >>> R. Walters >>> r...@solarray.com >>> Solar Engineer >>> >>> >>> >>> >>> On Mar 24, 2010, at 7:04 PM, drake.chamber...@redwoodalliance.org wrote: >>> >>>> Can anyone tell me why PV is considered an excellent battery charger? I >>>> think it is, only after the addition of a MPPT charge control. >>>> Otherwise, >>>> the battery drags the PV voltage below Vmp. >>>> >>>> One of the NABCEP objectives for the entry level class is to explain why >>>> PV modules make excellent battery chargers and show this through the IV >>>> curve. >>>> >>>> Thank you, >>>> >>>> Drake >>>> >>>> _______________________________________________ >>>> 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 >>> >>> >> >> >> _______________________________________________ >> 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 > > _______________________________________________ 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
