HI Daryl; Your experiences with the water pump got me to thinking that a water pump has a MaxPowerPoint as well. (Flow rate x head) As you varied the flow rate, you were also MPPT ing the pump- inverter system. You found max current at the middle of the pump's range, just like a solar module.
Also, on batteries, I found as you did, that a single string of L16s or T105s could not deliver the required current for very long to either start or run a large load like a pump. I currently ( no pun intended) think that two battery strings are optimum, for this and other reasons. I'd third the others input, that a generator is the best choice for a fire suppression pump. It won't be used at all most of the time, and then it needs to run continuously for hours in a very critical application. Instead of a huge battery bank and wall of inverters, the money might be better spent on a quality generator with reliable fuel supply (underground propane?) and more PV with a nice grid tie system. Loads that can't be interrupted for a few seconds while the generator comes up to speed, (computers) could be on their own UPS, or have a smaller Outback system. The efficiency of a grid tie system diminishes with increased battery size, though. R. Walters [email protected] Solar Engineer On Aug 28, 2010, at 5:24 AM, Darryl Thayer wrote: > Sorry this could be more helpful if I had a better memory, I don't mean to > ramble, but some wrenches may find value. > > I am working on a standalone system now and I am in testing. Normally I use > OUtback, (and I am very happy) and this time I decided to use Magnum 4024 > AE. The job has both a large motor and is AC coupled to DGI inverter. The > large motor draws over 120 amp (120 volt) surge when connected to a grid > source. I have started this motor in test repeatedly My Greenlee amp clamp > says it is surging at 90 amps! The VOM says the min voltage is 97 volts. This > is on ONE 4024 AE, Magnum is getting close to release of the paralled > version The test battery set is Trojan T105 single string, and the surge DC > measured by Ideal DC clamp on is 280 amps. Voltage and minimum battery > voltage is 21 volts Ideal VOM. I would think that the parrellel version > could handle your motor. > > Old system > I did a fire pump install in a large residence, I think back in 2004? the > specs were similar except the starting surge was higher and the running was > almost the same (maximum of 20 amps and less depending upon flow). I used an > Odd number of OUtback inverters (5) but not all were to this task. First the > starting surge measured by my greenlee clamp-on amp meter was higher on the > grid than it is on the inverters. I did a lot of field tests, however I do > not know where I put the data. I noticed that if I had fully charged > batteries the starting was 100% reliable but on batteries at near 50% SoC the > system started to fault on "low AC" during start-up The batteries were L-16 > Surrette 48 volt string. If the system was started every five minutes it > would fault, but if a longer waiting period I remember during the course of > the job I started the pump over 100 times in test mode with out a failure. > (this system gets annual tests and no problems so far) > > Pumps: We found that the pump current draw depended upon the flow rate we > allowed.. If we had one head open, the current draw was less than all heads > open. The maximum curent draw was at some flow rate in the middle flow > range! The starting surge was independent of whether the valve was open or > closed. If it would be possible to use a SQflex this would be a good choise. > Finally this system is grid tied and has a relay to Outback if the Grid > should fail and it has a generator inlet box if a generator is avaiable to > take the load. > > --- On Fri, 8/27/10, Joel Davidson <[email protected]> wrote: > >> From: Joel Davidson <[email protected]> >> Subject: Re: [RE-wrenches] Inverter for fire protection pump >> To: "RE-wrenches" <[email protected]> >> Date: Friday, August 27, 2010, 9:50 PM >> Hi Ray, >> >> Thank you for your input. The pump is part of a fire >> protection system that sucks water out of the swimming pool >> and pumps it to roof sprinklers with fire retardant added to >> the water. I'll forward your email to my colleague who has >> the details. >> >> Best regards, >> Joel Davidson >> >> ----- Original Message ----- From: "R Ray Walters" <[email protected]> >> To: "RE-wrenches" <[email protected]> >> Sent: Friday, August 27, 2010 7:23 PM >> Subject: Re: [RE-wrenches] Inverter for fire protection >> pump >> >> >>> Forgot to mention the usual info: look at the pump to >> see if a smaller or no surge Grundfos SQE might be able to >> handle the flow rate and pressure needed. >>> Pumps are cheap, when you're considering multiple >> inverters...... >>> Given what you mentioned (110 amp surge at 240 vac), I >> don't think even a quad stack of Outbacks could do it. ( >> please ignore my earlier post) >>> A quad stack could run that, just not start it. >> Franklin makes a soft start controller, that might work with >> that pump. What is the Horse power rating? >>> >>> R. Walters >>> [email protected] >>> Solar Engineer >>> >>> >>> >>> >>> On Aug 27, 2010, at 3:52 PM, R Ray Walters wrote: >>> >>>> Little beyond a pair of Outbacks, possibly a >> pair of Magnasine inverters, or a quad stack of Outbacks. >>>> >>>> R. Walters >>>> [email protected] >>>> Solar Engineer >>>> >>>> >>>> >>>> >>>> On Aug 26, 2010, at 2:41 PM, Joel Davidson wrote: >>>> >>>>> Wrenches, >>>>> Our customer has a fire protection pumping >> system that operates at 240VAC and 22 amps with a 110 amps >> starting surge. The pump will only be used for up to 4 hours >> in an emergency (but hopefully never). The customer wants an >> inverter and battery (no generator or PV) in case grid power >> is destroyed by fire. What inverter(s) do you recommend? >> Thank you very much for sharing your off-grid knowledge. >>>>> Joel Davidson >>>>> >>>>> >> _______________________________________________ >>>>> 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 >> >> > > > > _______________________________________________ > 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
