pgtruspace's blog

about things that interest me.

Monthly Archives: August 2021

8 Kw of PhotoVoltaics

Another project underway.

40 Photo Voltaic panel array

40 – 200 watt Sanyo PV panels installed on a wooden rack with a winter orientation. The panels are arranged as shingles to provide a dry area under them for the wooden framework as well as a place for power management and battery storage area.

You will notice the steep angle of the panel array. This is to maximize the winter production at the expense of summer production. The best average inclination is the same as the Latitude of solar collection, then plus up to 15degrees for maximum winter power production, or less up to 15degrees for summer maximum production.

construction started
40 panels with outriggers
30 panel rack design

This spring, a bunch of used lumber became available to create the rack to mount them on, so I built it on the space available that had a suitable “Solar Window”, something not common in the woods.

I first planned on a 25 unit system but as I designed found that a 30 panel rack was possible on the base created because of the steep winter angle. After much consideration that grew to 40 by adding outriggers on the ends. An important part of the design was to shingle lap the panels to provide a dry environment for the wood frame and equipment below.

Now that it has been built I found that the best “window” available is where the green pickup was parked so I moved the pickup as well as the old equipment behind it. Now at this point the entire rack has been moved about 15 feet to the south., But that will increase the usable “window” from 6 hours to 8 hours. A gain of nearly 10% in possible energy production. 8 hours is about the maximum effective “solar window” that a fixed array can utilize. When you build in the woods tall trees cast long shadows. But an added benefit of the move is that I can add another row of 8 panels along the bottom of the rack frame because of abrupt elevation change of ground level at this point.

Nearly 3 years ago we had the opportunity to buy 50 used, 200watt 10year old Sanyo panels for a very good price and brought them home.

stack of Sanyo PV panels

Sanyo HIP205-BA5 Photo Voltaic panels

Max Power 205 watts

96 cell ( 48vdc )

maximum voltage 68.8vdc

maximum current 3.8 amps

maximum operating voltage 56.7vdc

We also bought 12 used Enphase Micro Power Point Tracker – mppt controller/inverters

M190 – 72 – 240 – s12……………190watt , 72 cell ( 36vdc ) 240vac, split-phase

22 – 44vdc input ( that is about 6amps at 40vdc )

240 vac – 0.8amp output split phase ( that is 120vac – neutral- 120vac or 240vac )

12 panels temporary set up in field

A dozen were set up in an open area with salvaged individual grid-tie controllers but the mis-match involved yielded very little power.

At best 3 amps at 240vac. from the 12 units at right. The ( 96cell ) panels can only output 3.8 amps @ their peak effective 57 volts to create 200 watts.

Solar panels are limited in their output amperage, in this case 3.8amps so that the panels could not develop enough energy to really load the controllers that wanted over 6 amps @ at least 44 vdc (72 cell) to power 190 watts. The panels open voltage is over 68vdc (96 cell) so if the inverters cycled off for any reason they would not turn back on during that day due to High voltage at the input. But if on would drain the panel below the needed 22 volt operating voltage.

To this I have 22 lead acid batteries of varying age and condition.

Now all this equipment. has been included in the erected system, and a bunch of wire and connectors has arrived so I can start hooking up things.

Now to put what I have learned from my mistakes into practice within this rack. Panels in series and parallel as well as batteries in series and parallel to balance the PV to the inverters. Also lots of power to reclaim sulfated batteries.

equipment area under the panel rack

Over 20 old batteries of varying quality are being hooked up for reclaim and test, As I accumulate parts and supplies the project grows.

This post will be under construction as I build the generation system.