solar

Posted By: walt26scolorado
Date: 4/9/09 8:45a.m.

Report: outside forum guidelines

In Response To: Solar panel comments, suggestions, musings... (link) (Chris & Lenore - Mac 26S Teliki)

Chris, since your into the circuit stuff, sometime check out P channel Fets. They can operate much like a relay but turning them on or off is very simple and takes pretty much no current. (example of one picked somewhat at random) http://ixdev.ixys.com/DataSheet/DS99967(IXTA-TP32P05T).pdf Sumner, I should have put a "poor attempt at humor" emoticon just after my "ex wife" comment. For about 7 weeks this year, I rent a slip at Cherry Creek in Denver. I dont use any power from the marina and its very much off season so I get a great price. The marina is on my way home from work and fairly close to where I live so I spend a fair amount of time there. The marina has wifi just this year so besides the stereo and lights (LED but I have five seperate LED fixtures), the lap top gets used there a fair amount. I have a charge monitor (not necessary but its a fun toy) so can watch current at any time and when I first turn on the stereo, it burns about 1.5 amps but after a while, settles in at about 2 amps. The lap top however uses about 5 amps. I have a 20 watt panel which works well during the summer when Im only using the boat one day per week but when I have the slip, it wont keep up with the use. The 80 watt panel on the other hand allows for some pretty decadent electrical use like in addition to everything else, having christmas lights on the shrouds etc. I use a charge controller (this one http://www.infinigi.com/morningstar-ss1012-sunsaver-10-charge-controller-p-832.html ). This type of controller uses a P channel FET to directly connect the panel voltage to the battery voltage. The P channel FET acts similar to relay - ie, either a short on an open so the FET is controlled by pulsing it on/off (ie, PWM). The micro monitors the battery voltage and also temperature and controls the pulsing to give three stage charging of the batteries. When Im using the boat during the day with the solar panels connected up, I can see the charge to the batteries going positive (ie, charging the battery) when the sun is bright and then go negitive (ie, discharge) when a cloud goes over. I dont need the 80 watt panel all the time but would like some lightweight support off the stern railing that was fairly easy to put on or remove (and didnt cost a fortune). On one side of the stern rail is the very important swim ladder and a barbeque on the other side so Id have to take these into account.