Hello again, Thanks to all of you who chimed in with suggestions and comments on this very apparent mis-application of the Solar Boost charge controller!!
In looking at options for them, I thought of using the Morningstar 15Amp MPPT controller. They have a cut-off of 70V DC on the Voc, and ask for an array not to exceed 400 watts. The system here in Senegal is a whole lot closer to meeting those criteria than the Solar Boost. (73Voc and 440 Watts/p) I have written to MS to see what they think about this. I hope to hear from Solar Boost to see their opinion, on what the best plan of action could be from their perspective. Chances are, Solar Boost has no idea the equipment was used this way. Some of you asked who designed this? I am not really sure, but there is a company named Earthwalk that primarily provides laptop computer packages for remote education facilities. They come with a battery charger cart for the laptop batteries that is designed to plug in at night (especially when there are problems with the grid power during the day.) The Earthwalk company provides as an "accessory" a solar charging station for locations without the grid. They include the system I described, but with a few other unusual design thoughts. (They use AGM batteries instead of GEL batteries, they have a new DR1524 inverter, and they use a Solar Converter Model VCS-2AH switch, that I think is being used as a Low Voltage Disconnect, and I think that is set at 20V....) These systems were assembled very nicely into a rolling cart in the states, and shipped to Senegal. (The 12V Dekkas are measuring 5V now, on this end before placing into commission.) So - it is likely that Earthwalk commissioned a "solar" company to build this for them. I am trying to find that out now. I just want to recommend the best action to them now instead of when all of the systems start failing...which I am afraid they will do very soon. I see enough failed systems. I would just like to stop this train wreck. Thanks again for all your input. >From the bush in Senegal!! Walt -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Larry Crutcher, Starlight Solar Sent: Saturday, June 27, 2009 7:42 AM To: RE-wrenches Subject: Re: [RE-wrenches] Solar Boost Controller in Senegal ...And the Voc is present every morning before the current is high enough to start the controller. That's when I would expect to have a problem. boB, I doubt that the Voc sample duration is long enough to cause a problem. I know that Rick got back on this list a few months ago so if you (Rick) have any input to help Walt, we welcome your comments. Larry Crutcher On Jun 27, 2009, at 2:35 AM, boB Gudgel wrote: > Wind-sun.com wrote: >> Yes, it is a poor design. though you may not have any problems >> there with the heat de-rating of the panels. If the panel >> temperature gets under about 40C you may blow out the input. As >> long as you have a load on the output of the contgroller, it will >> keep the voltage down, but if the output is disconnected the input >> could go up to full voltage. > > Remember that this controller opens up every so often, (8 seconds or > so?) to check Voc and adjust the MPP-V based on that measurement. > > boB > > > > >> Who designed such a system? >> ............................................................................ ...................... >> Northern Arizona Wind & Sun - Electricity From The Sun Since 1979 >> Online Store: http://store.solar-electric.com/ >> Solar Discussion Forum: http://www.wind-sun.com/ForumVB/ >> ............................................................................ ...................... >> >> ----- Original Message ----- >> *From:* Walt Ratterman <mailto:[email protected]> >> *To:* 'RE-wrenches' <mailto:[email protected]> >> *Sent:* Friday, June 26, 2009 3:22 PM >> *Subject:* [RE-wrenches] Solar Boost Controller in Senegal >> >> Hello, >> >> >> I am in a very remote part of Senegal, (near the Guinea and Mali >> borders.) and I have come across some prefabricated "plug and >> play" American made systems installed for educational institutions. >> >> >> The systems use two Sharp panels that are 220Watts, 33.6 Voc, 29.2 >> Vmp, wired in series, using #10AWG home run wire from the panels >> back to the charge controller. >> >> >> Charge Controller is a Solar Boost 50. >> >> Batteries are Dekka AGM - two strings of 250AH, 12V >> batteries. (four batteries total). >> >> >> My specific question is about the controller. This is a 24V in / >> 24V out charge controller with MPPT. I have not used this before, >> so I am not familiar with the details of operation. >> >> >> The data sheet that I downloaded says that the maximum open >> circuit voltage is 57 VDC. But, this system is hitting the charge >> controller with two panels of 33.6 VDC wired in series for >> 73.2VDC. So, why is the controller not fried, or what am I seeing >> wrong here. I suppose with the panel temperature being elevated >> maybe 35 degrees above 25 degrees and a resulting 17.5% loss, >> coupled with some voltage drop, the system may actually be seeing >> less than the 57 volts... > _______________________________________________ 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 __________ Information from ESET NOD32 Antivirus, version of virus signature database 4193 (20090626) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.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
