Found the power was way down on the solar panels
on my boat. Two 37 Volt 195 watt SunPower panels
bought in the mid 2007 & installed with a MTTP controller. Paid by today's standards a premium amount for the supply only & fitted it up myself. Now the seller has moved on so I rang SunPower (Australia). I told them of the problem & supplied serial
Nos, invoice details etc expecting a battle but instead the response was after a few emails "we will supply two new panels
of the current
models & we will arrange one of our installation
companies to replace then on your boat at no cost to you". In the period 2007 to 2014 the same physical panels produce 20% more power as well. (E19/238 panels supplied). The system kept supplying power at a reduced rate by virtue of the bypass diodes built into the panels. The stored infomation in the MTTP only covers the last 65 days & it shows faulty for that period.
Also found previous logged data from 2010 on old laptop
when new battery
was installed, showing fault was actually recorded but not noted by me as I was testing how long in time & how much power the freezer
required as the prime concern was measuring power from battery
. A channel on the logger was on the PV & it was recorded diving
under light load.
Initially I thought by some of the details exchanged with SunPower, that my installation
was to blame because of the need to have a "passive positive ground" with the original panels. Not needed on these newer panels. The installation is mounted on plastic insulated rail mounts & that was disregarded.
It is nice to hear of a good outcome when dealing with a large company if something goes wrong. The tech support was excellent. The installation team turned up on time as arranged & carried out all the work.
Over 300 Watts for 20+ Amps into the battery & that I have never seen before. Panels are mounted flat so some degrading of the output has to be expected but this result is good.
Just keep this story in mind when you are looking for panels. Companies come & go but at least the larger ones give the best value for your dollar.
Regards Bill Goodward ( have no connection with SunPower or their dealers).