HI all the resistor bank that I used was the 240 volt water heater elements. They seem to be quite cheap/ They do glow a real dull red on 24 volts, and I will try to measure the resistance. for adjustment use a parallel set of 500 watt halogen work lamps. I use a combiner box and MNsolar breakers, the 1/2" wide ones. connect the switches to recpticles, and the elements to cord ends. and you can put a duplex recpticle to connect two loads in series. Darryl
--- On Wed, 12/17/08, Peter Parrish <[email protected]> wrote: > From: Peter Parrish <[email protected]> > Subject: Re: [RE-wrenches] Sealed battery test/maintenance > To: [email protected], "'RE-wrenches'" <[email protected]> > Date: Wednesday, December 17, 2008, 11:22 AM > I am very interested in this thread as we too have about a > half-dozen > grid-tied battery backup system in the field. I used to be > a ham radio > operator and I remember using large, wire-wound resistors > encased in an > aluminum casing. The case could be bolted to a heat sink. > > I looked up one of these puppies and found them rated up to > 50W continuous. > > Here is a simple tester: > > Assume a single 12 V battery. If you want to test battery > banks, I think > that that would be a different ballgame altogether. > > Use a number of 5 ohm / 50 watt resistors in parallel. The > number you use > depends on the current you want to test to. Assuming that > you want to run at > C/20, here is how you determine how many resistors you > need. > > A 5 ohm resistor will draw 2.4 amps. Assuming C/20, a > single resistor would > be an appropriate load for a 48 Ah battery. The power drawn > is 28.8 W which > is fine for a 50 W resistor as long as it is bolted to a > good heat sink. Two > 5 ohm resistors will draw 4.8 amps, appropriate for a 96 Ah > battery. The > general formula is "battery capacity divided by 48 > gives you the number of 5 > ohm / 50 W resistors you need in parallel". The power > dissipated in each > resistor will always be the same regardless of the number > in parallel. > > I will probably rig one of these loads up one day soon if a > better solution > isn't out there already. > > One could add a high current switch or DC rated circuit > breaker, voltage > probe point and a high precision shunt to measure current. > > I have no idea what sort of voltage as a function of time > should be. Has > anyone spoken to battery manufacturers about the specs > under C/20? > > - Peter > > Peter T. Parrish, President > California Solar Engineering, Inc. > 820 Cynthia Ave., Los Angeles, CA 90065 > Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 > CA Lic. 854779, NABCEP Cert. 031806-26 > [email protected] > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On > Behalf Of Glenn Burt > Sent: Wednesday, December 17, 2008 7:41 AM > To: 'William Miller'; 'RE-wrenches' > Subject: Re: [RE-wrenches] Sealed battery test/maintenance > > Thanks for the reply William, > > When you load the battery bank, are you using the inverter > as the source of > the load (obviously with its loads), or do you use an > independent DC load > like a carbon pile (auto battery tester)? > > Glenn > > -----Original Message----- > From: William Miller [mailto:[email protected]] > Sent: Tuesday, December 16, 2008 2:07 PM > To: [email protected]; RE-wrenches > Subject: Re: [RE-wrenches] Sealed battery test/maintenance > > Glenn: > > There are a combination of tests, none as decisive as we > might like: Load > the battery bank and test per cell voltage (more often we > find warm > connections revealing related problems). Measure the at > rest voltage. > Measure voltage over time at load. If you are serious > about this, establish > base lines when batteries are new. > > Good luck. > > William Miller > > > At 09:55 AM 12/16/2008, you wrote: > >Good Holiday Season to all: > > > >Does anyone have a sealed (gel & AGM) battery > test/maintenance > >procedure they would feel comfortable sharing with the > group? > >I have been tasked with creating one for our company > now that we have > >more than a couple of grid tied systems with battery > backup. > > > >Hate to re-invent the wheel with so much talent > available here. > >Thanks in advance! > > > >Regards, > > > >Glenn Burt > >Technical Specialist > > > >Renewable Power Systems, LLC > >PO Box 967 > >Averill Park, NY 12018 > >V: 518-674-5808 > >C: 518-810-3174 > >F: 518-514-1175 > >E: [email protected] > >www.RPSpower.com > > > > > > > >_______________________________________________ > >List sponsored by Home Power magazine > > > >List Address: [email protected] > > > >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: [email protected] > > 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: [email protected] > > 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: [email protected] 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
