January 9, 2019

Solar Energy

At this time, this information is quite specific. I am working with a remote and isolated installation with solar panels, a charge controller, an array of lead acid batteries, and an inverter.

The panels

We have 6 panels, all wired in parallel. Actually there are three physical panels, but each physical panel has two independent sections, labelled as follows:
Siliken Standark Photovoltaic Module
SLK60P6L 230W +- 5 percent
29.5 volts Vmpp  36.9 volts Bcc
7.69 amps Impp  8.32 amps Isc

The batteries

We have an array of 6 plain old 12 volt lead-acid car batteries, with two groups of 3 in parallel - set up as a 24 volt battery. Note that deep cycle batteries absolutely should be used for a photovoltaic power system.

The charge controller

Our charge controller is a Xantrex XW Solar Charge Controller, model XW-MPPT60-150. Xantrex is/was owned by Schneider Electric. They provide a toll free number 1-866-519-1470. List price for one of these is $685 - in 12/2012 Amazon sold them for $600.

The current (2012) xantrex website has no mention of our unit that I can find, but documentation can be found via google searches. Comments on various forums indicate that Xantrex customer support is horrid (on good days), worse otherwise.

The "Xantrex" (as I will call it from now on) is rated for up to 140 volts input (while operating, 150 volts open circuit) and 60 amps. We are now running it with all the PV (photovoltaic) units in parallel, feeding it 36 volts and 48 amps.


The largest wire that should be used is 6 gauge wire for any of the ground, PV array, or battery connections - to fit into the connectors on the Xantrex in any event.
Have any comments? Questions? Drop me a line!

Tom's notes / tom@mmto.org