No announcement yet.

Building Reserve and Using KWH

  • Filter
  • Time
  • Show
Clear All
new posts

  • #91
    I believe another challenge for the direct burial heavy feed has been solved.
    The digger on my 18 inch deep trencher has been lengthened enough to
    reach 24 inches. Will not push it too hard.

    I still need to locate the original buried power cable, to avoid hitting it. Bruce Roe



    • #92
      Originally posted by bcroe View Post
      I believe another challenge for the direct burial heavy feed has been solved.
      The digger on my 18 inch deep trencher has been lengthened enough to
      reach 24 inches. Will not push it too hard.

      I still need to locate the original buried power cable, to avoid hitting it. Bruce Roe

      They make "buried cable locators" that will send a signal down a buried cable that can be "sensed" by a receiver and avoided. Maybe you can rent one.


      • #93
        Originally posted by SunEagle
        They make "buried cable locators" that will send a signal down a buried cable that can be "sensed"
        by a receiver and avoided. Maybe you can rent one.
        Yes I have a couple different ones, but so far have not been able to follow the signal. I
        might set up lights for night operation, open all breakers at both ends of the run, and
        see if that helps. Bruce


        • #94
          With favorable weather (no snow), the adventure continues to install a heavy wire run out to
          the shed with the inverters. Already running out there Is a triple 4 ga, a phone style cable, a
          water line, and a cat 5E to the tower. So lets find existing cables with a cable tracer/wire
          locator and mark them with flags. Have a Tempo 508S and a Kolsol F02 which seem to have
          identical specs at 447KHZ. The former Ebay cripple had a bad transmitter, and the latter new
          unit had a bad receiver. I got results with the 508 receiver and the F02 transmitter.

          The breakers at both ends of the 4 ga were opened, and the tracer signal applied to one
          end of a de-enerized 240V wire. Return was to electrical box ground.

          Seems like you cannot have too many flags. Red is my 4 ga pwr, a couple feet down. Also
          detected, white flags, is my Cat 5E from the dish on my tower, barely below the surface. Not
          detected farther west, are the phone cables I buried in 2004 and a water line. I do believe I
          can detect a slight depression running along the ground from the original 4 ga trench. Think
          that sudden jog is a big rock?

          The plan is, start by trying to get a trench under a huge root for a big tree without actually
          cutting it, go from there to house wall. Unroll 4/0 triplex cable under the root and into the
          house, then work the other way to the shed. The current cat 5E will try to lift up and work
          under it, will also lay a new one half way down to the 4/0. Measure exact distance from
          buildings for future reference.

          I do have another tracer that operates at 125KHZ. Completely different ant, will see if it is
          useful in this situation. Need to build some kind of dolly for that very heavy reel of 4/0 triplex.

          Bruce Roe


          Last edited by bcroe; 01-07-2020, 10:26 PM.


          • #95
            Overnight was a serious test of the car shop heat pump. With an output of up to 24,000 btu
            it has been set for 60F in the 1080 sq ft, modestly insulated building. This had been
            maintained in warmer weather. With 3F this morning the interior was 53F, so a 50F differential
            may be maintainable. It may do less well if we see Neg 25F outside, the pump effective
            limit, but any of these are way better than no heat. A propane furnace stands by to make
            up the difference if ever needed, but has not been used this winter. Bruce Roe
            Last edited by bcroe; 01-19-2020, 10:28 PM.


            • #96
              First time this winter the temp got down to minus 10F. The 4 heat pumps managed to keep
              the house in the 70s without any action from me. The out building (1 big heat pump) also
              managed to stay 55 degrees warmer than outside. The next big test is - 20F. Bruce Roe


              • #97
                Thanks for the updates and demonstrating that we can all have different goals. The important issue is to have a well though out process to accomplish our goals.
                9 kW solar. Driving EVs since 2012


                • #98
                  Another solar year, the PoCo reset date was reached 30 March. I gave them my surplus of 4,240 KWH.
                  That is a surplus of around 18% over usage. No propane heat was used in keeping 2 buildings in a
                  very comfy temp range. The winter might be summarized as having relatively cold fall and spring, but
                  relatively warmer winter. No resistive or propane backup heat was used, the heat pumps did it all. It is
                  easy to imagine a much more severe winter using up all my energy reserve and more.

                  The heat pumps have reduced to a NEW LOW, my labors and attention to managing energy. Things
                  pretty much run themselves, with some snow removal required by me, just a part of the cleanup of drives
                  and walkways here. Sort of like those Medallion Homes after the war, but I have even more stuff and do
                  not pay for energy. A few problems not originally anticipated have been solved, some using technology
                  not originally anticipated.

                  Future improvements anticipated include recovering close to 800 KWH annually lost in transmission
                  between buildings, by burying much larger aluminum wire. The prep work is in place at both
                  ends, on site are the 24 inch deep trencher, and the 300 lb of wire on this cart to avoid much manhandling.


                  Also possibly install an electric water heater, with a propane unit remaining as power outage
                  backup. 5 rooms are prewired to get ceiling fans, or at least high efficiency overheat lighting.

                  I am waiting to see if a certain tree is dead, before making a final revision of best array placement.
                  Foundations can be worked on half the year, above ground stuff longer. This is not high priority,
                  but each section completed will give an incremental decrease in snow removal efforts and some
                  additional energy. In one case I just drove the snow blower by the newest array with
                  blown snow hitting the top, and the little snow just fell off without manual effort.

                  I am thinking of no longer making daily performance log entries, perhaps
                  just record about the time of the monthly meter reading by the PoCo.

                  Bruce Roe
                  Last edited by bcroe; 04-10-2020, 12:06 PM.


                  • #99
                    With net metering resetting my reserve KWH to zero at the end of March, the challenge is
                    to get through April generating more KWH than used, so I do not need to buy any. To add
                    more challenge, this is my first April with 5 heat pumps on line keeping 2 buildings comfy.

                    Sat and Sun each generated 149 KWH, amazing in these parts. That requires the 15 KW
                    plant to run flat out saturated some 9 hours and 48 minutes each day. That is only 8 KWH
                    short of my best June day record. Not to worry, I am not only breaking even, but my
                    spinning disc reserve meter shows more than 800 KWH reserve already built up. Those
                    heat pumps are just so efficient. Bruce Roe


                    • Wow, that's just awesome Bruce, Thanks for all your documentation and information.
                      Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                      || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                      || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A



                      • Originally posted by Mike90250 View Post
                        Wow, that's just awesome Bruce, Thanks for all your documentation and information.
                        It is not as awesome as being off grid, but I am way too lazy for that. Bruce


                        • Generally by 9am this time of year, a visit to the inverter shed reveals the twin 7.5KW
                          solar systems are both saturated at full power. That even if a slight bit of cloud is
                          present, with this arrangement. But a couple days ago one system was down some
                          hundreds of watts from the other. I decided to wait a day for better sun, got the same result.

                          OK, a quick walk around with the clamp on DC ammeter revealed, String 9 was putting
                          out ZERO current. I actually had been a bit suspect of somewhat reduced output from
                          S9 before winter, but tests had not revealed any fault. I went to the combiner and pulled
                          the S9 fuse, S9 was delivering zero volts.

                          At the array, some test points I had left in place revealed substantial S9 output available.
                          Apparently the string was not connected to the combiner. More checking revealed this
                          failed MC4 connection of the string return connection.


                          Why is that a 3 way connection? This 2 sided array has strings facing East and strings
                          facing West. To save wire an E and a W string share a common return, since they could
                          not both deliver peak output at the same time. Even if they had, the return wire would
                          not be overloaded. I decided to wait for dark for a simpler and safer repair job, an
                          outdoor outlet on the end of this array would power a light.

                          So what was to be learned from the 7 years of experience with several hundred MC4s?
                          First my ability to compare the 2 systems at a glance had immediately demonstrated this
                          serious fault.

                          2nd the output difference between the saturated system and the faulted system showed
                          that the total number of panels facing E (in this case) was about right. A properly
                          operating system generated enough power to saturate the inverter, but not enough to
                          mask the loss of any section.

                          3rd my past warnings about MC4s were not excessive. Perhaps this one got a bit
                          of weather exposure, and/or perhaps the seals were not moisture tight, and the
                          heating/corroding daily cycle finally escalated and destroyed it. In the future all
                          MC4s here will receive a dab of anti-oxidant compound as insurance.

                          4th this will probably not be my last MC4 failure.

                          Meanwhile, the weather is improving, and the project to trench 4/0 aluminum wire
                          out to the inverters may start soon. Conduit coming out to a trench is near
                          complete, and some dirt has already been moved. Bruce Roe


                          • The PoCo bill came, I looked over the first 2 months of this net metering period. 2 years ago I was not
                            running the 5 mini split heat pumps. By subtracting reserve built up from inverter generation, I have a
                            pretty good idea of my KWH consumption. Going back 2 years, the consumption for April-May was
                            about 46.3 KWH a day. The past 2 months consumption was about 31.6 KWH a day. I am going to
                            credit this 32% reduction in use to the increased efficiency of the mini-split heat pumps, over the other
                            heaters. It would be even more, except an additional building is now being temp controlled.

                            Had a brief issue 29 May, both inverters went off and were having trouble getting back in service. Half
                            an hour later things were normal again, doing about 50% of capacity under some clouds. I guess there
                            must have been some kind of line fault, later I noted it was about 120/240VAC even with the inverters
                            pushing, think that has dropped a bit.

                            Meanwhile the new AC feed trenching is inching along. With all the rocks, that
                            term may be too optimistic. Millimeters? Bruce Roe