Hi Gary, We have implemented a preheat strategy that has really worked well at a site using dual sunny islands. They have a load shed function built in with the control relays. We are using that function to add the block heater load. When a generator start is likely (~50% SOC) it triggers a relay that energized the block heater. The generator start is then programmed at a lower SOC (~30% SOC). It takes some guesswork to know how many watt hours its going to take to get the block heated up, but we conservatively chose and have fiddled with it. I imagine this can be done with either the Radian or the XW, and you could trigger with voltage instead of SOC, but SOC is a superior way to do it.
Another way is to use a propane block heater. This will work well, but they use quite a bit of propane, and are very expensive (~$1500). Good luck On Thu, Apr 2, 2015 at 8:47 PM, Gary Higbee <g...@windstreamsolar.com> wrote: > Wrenches, > > I'm curious what strategies you use to preheat a propane gen in cold > climates. This is a large off-grid design in a sub-zero winter climate and > ideal would be to turn on a block heater an hour or two in advance, then > run the gen cycle. We plan to use either a Schneider XW or Outback Radian > configuration (still very interested in which you'd use and why). We could > set up a logic/relay system to first send the gen request to the heater for > a while and then turn off and initiate a gen cycle but that would eliminate > the ability for autostart on short notice. I've read of heat lamps on a > thermostat, just wondering if you have seen other solutions. > > Thanks! > > Gary > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > -- Mac Lewis *"Yo solo sé que no sé nada." -Sócrates*
_______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org