Wow! What the cost of your system?
- Mark Sent from my Fuel Cell powered iPhone > On May 28, 2020, at 8:16 PM, Tom Keenan via EV <[email protected]> wrote: > > For those interested, here is a slightly more detailed write-up of my solar > power system at home. > > The supplier for my system is Electriq. They provided a Darfon(Panasonic) > charger/inverter and the Panasonic batteries. I believe the battery cells are > similar to the ones used by Tesla, but am not sure. > > The inverter itself runs at 48v (nominal). I have six sets of 48v batteries > wired in parallel to the charger/inverter input. Each of the individual units > of the six pack is rated around 3 kWh, but in practice they are kept to about > 2.5 kWh by limiting how far up and down they can go while charging and > discharging in order to maintain the health of the overall battery system. > Thus gives me around 15 kWh at about 48 volts for the battery. > > The solar array is two strings of six panels, for about 2kW (@240v) for each > of the two strings, making it a 4kW (nominal) system. Depending on the sky > clarity and temperature, I’ve seen the array put out up to 5kW for brief > periods of time. More normal to see it around 3.8 or so kW. If I had to do it > again, I’d have two strings of 7 panels to make the MPPT more robust. But > putting up two more panels and this point would only add to the amount of > ‘credit’ I’ll lose at the end of the year, so I’ll take the efficiency hit. > > As it is, the voltage of six panels is on the edge of being able to use > inverter-based MPPT or not, depending on how much sun they are getting. > Generally the voltage is just a little bit (1 or 2 volts) too low to work > consistently. With an extra panel in the string, it would normally be in MPPT > mode. Unfortunately, I can’t simply combine the 12 panels into one string, > because even though the voltage would be very good, the total power is higher > than the inverter can handle on a single string (3.7kW max per string). > > The inverter is rated at about 5.7(?) kW continuous, but will peak higher for > certain brief periods. I saw it around 8kW once when I plugged in my EV > without first checking the charge amp limit, and it handled it gracefully. > > I will be charging the Kona tomorrow because I drove it about 50 miles this > evening. I’ll plug it in around 10:30 am after the house battery has finished > charging. Depending on how sunny it is, and if it is warm enough that I want > to turn on The A/C in the house (not likely), I’ll set the car charge amps > somewhere between 10 and 20 amps (@240v). > > Tom Keenan > >> On May 28, 2020, at 7:11 PM, Willie via EV <[email protected]> wrote: >> >> Thomas's post didn't make it to me. I'm pleased to see it completely >> quoted here. >> >>>> On 5/28/20 8:09 PM, Alan Arrison via EV wrote: >>> Tom, could you give some specifics on this system, or point us to a web >>> page? >>> What battery? What inverter? >>> Thanks, Al >>>> On 5/28/2020 1:24 PM, Thomas Keenan via EV wrote: >>>> Where I live, the local utility has some odd rules, but I do get credited >>>> $0.06968 for each kWh given back to the grid. I have a permitted 4 kW >>>> array that feeds a Darfon/Panasonic inverter/charger for a 15kWh (useable) >>>> battery that was commissioned in January. The battery covers times when >>>> the panels aren’t putting out enough to power the house, such as >>>> overnight. Overnight, the house uses two or three kWh that comes from the >>>> battery. In the morning the battery recharges, and is typically done >>>> charging around 10:30 in the AM. After that, any excess is sold. >>>> >>>> This inverter/battery setup has been working very well. The battery has >>>> not been below about 50% so far, and that was during a three-day rain >>>> event where the system wasn’t producing much. Aside from those (somewhat >>>> rare) rain events, I generally have around 10-20 kWh excess that is sold >>>> back to the grid daily. >> >> This is much the same as my PowerWall set up which has been running about 15 >> months. The PW allows me to avoid all electricity purchases. But the PW >> cost can not be justified by the savings. >> >> I sell over production for $.0645/kwh and buy at about $.10. The PW allows >> me to not buy about 10kwh each night. So, my daily savings from using the >> PW is only about 10 x ($.10-$.0645) or less than $.50/day. I don't buy the >> 10kwh at night but I have to use 10kwh during the day to charge the battery >> and thus do not sell that 10kwh. The PW cost $13k. I justify that cost with >> grid down security. >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> ARCHIVE: http://www.evdl.org/archive/index.html >> INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) >> > -------------- next part -------------- > An HTML attachment was scrubbed... _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
