jonr ✭✭✭✭


Last Active
Solar Expert
  • Re: Desperately Seeking Normally Closed Latching Contactor (but not that desperate)

    The wine bottle analogy is good for a system with a capacitor based active balancer.  The balancing flow rate between bottles/cells depends on the difference in height/voltage.    A inductor based active balancer is different - more like someone moving a fixed flow (say 1 cc/sec) between bottles.   A top balancing bleed/shunt balancer is like a small hole near the top of each bottle - dumping a little wine when the level is too high.  Any of the balancing methods can be overwhelmed by filling too fast - you need to slow down when any bottle is close to overflowing.

    I'm surprised that people still have to worry about cell balancing.   Should be able to just buy a combined charger/balancer/BMS that handles everything.  And can be powered from a variety of sources (say 30-150V AC or DC  with optional MPPT).
  • Re: does it matter when i use most power?

    When (as in daily) effects wear on the battery.  Given a choice, use power while the sun shines (which also provides an efficiency gain).  If that's not possible, then the early morning hours  (to minimize the time the batteries are discharged).  Worst is around sunset.

  • Re: I want to run my water heater on solar power (Newbie)

    How long an off time is needed for an arc to extinguish and then not re-form is apparently a complicated question.  So is how far apart those off times can be without excessive contact damage.  
  • Re: I want to run my water heater on solar power (Newbie)

    This is well worth reading if you want to heat water with PV solar.  With some low cost panels and a DIY install, the economics look pretty good (depending on what other options you have).

  • Re: Supplementing off grid system with extra AC

    On the other hand, 120hz microcycles are only about 2 millionths of the batteries capacity.  I doubt that counts as a "cycle".