Daniel; I've had good luck with the Samlex DC-DC converters for running 12VDC lighting loads from a 48VDC battery bank. With a DC overload they sound an audible alarm and shut down, but reset automatically when the overload is cleared. They can also be paralleled so no need to select different DC branch circuits assigned to each converter to balance loads..
Dan Fink Professor of Solar Energy Technology, Ecotech Institute IREC Certified Instructor™ for: ~ PV Installation Professional ~ Small Wind Installer Executive Director, Buckville Energy NABCEP Registered Continuing Education Providers™ 970.672.4342 On Mon, Jan 15, 2018 at 1:32 PM, Daniel Young <[email protected]> wrote: > Hello Wrenches, > > > > I have a client that is running into an issue with his off grid system. > The system is 3yrs old and they are starting to notice their AGM battery > bank is loosing capacity, in reality they are noticing the generator is > triggering more often. They want to try to lower the frequency of the > generator triggering if possible. > > > > The system is not occupied during much of the winter (unconditioned, which > further hurts the battery bank capacity), but the client has a security > system with a cell modem installed and always on. This fortunately allows > Optics-RE access, but unfortunately based on the FNDC shunt readings, is > pulling a consistent 150w from the battery bank. Currently the network and > security equipment is powered from standard wall-warts running on AC. > > > > I’d like to help the client extend the time between generator cycles by > taking the network loads and powering them directly from the battery bank > (the loads are all 12Vdc). Does anyone have any recommendations for a > decent quality DC_DC converter that would be applicable? Given inverter > losses and the efficiency of the typical wall-wart, I’d expect the running > loads to be closer to 80-100w rather than the 150w we see now. The intent > is to then take the inverter into search mode, or even switch it off, to > remove the tare losses there, and also to take all the wasted power from > the standard wall-warts and go to a single, more efficient dc power supply. > > > > Any recommendations on a good DC_DC converter are appreciated. > > > > With Regards, > > > > Daniel Young, > > NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90 > > Dovetail Solar and Wind > > > > ________________________
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