Tuesday, July 4, 2017

Solar System Two

Trying to meet CPAP requirements:

http://www.healthyresources.com/sleep/magazines/psnews/power03.html

    here are the three parts:
the panels, order now on ebay ($160)

http://www.ebay.com/itm/Mono-Poly-PV-Solar-Panel-160W-100W-90W-40W-25W-10W-5W-12V-24V-RV-Boat-Camping/361878817780?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

    Costco batteries:
    best is 140wh (2 70wh deep cycle costco batteries)

charge controller:

    http://www.ebay.com/itm/5-10-15-20-30A-PWM-Solar-Panel-Battery-Regulator-Charge-Controller-CE-12V-24VMS-/272672199604?var=&hash=item3f7c8793b4


extension cables:

http://www.ebay.com/itm/1-Pair-TEMCo-10ft-MC4-Solar-Panel-Extension-Connector-12-AWG-PV-Cable-Wire/281368913995?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649



Wednesday, February 15, 2017

Inexpensive Solar system

Solar panel Notes:
Optimum angle for solar
              Fixed--~30 Degrees
Two season
              Summer (march 30-september 12th)- ~8 degrees
              Winter (rest of year ~45 degrees).
Sites:
Note, angle for grid-tie is very different than off-grid.  (because you are watching for optimal energy generation the whole day.

For the mini off-grid installations, current position is good for winter (until march 30), lay on top during summer.

Batteries for mini-grid
System works for either 12 or 24 volt battery systems (however, you need different output systems for 24v)  For simplicity, I recommend all small systems stay at 12v.
You can use 2 6v batteries in series to get 12v, but they must be very very similar.
Checkout of Battery
Battery checkout is the most dangerous step.  It is a little safer to do battery checkout with a smart charger (from 110), but it can be tricky in other ways.  (I had fully discharged batteries take days to recover on a charger, but I think the charge controller would have quickly worked).
Do not attach a battery directly to an array of batteries.  (Even a good battery could rapidly charge, generating hydrogen, and explode, spraying sulfuric acid.)  Battery testing should be done outside.  Batteries should always be on a thermal insulator (like a piece of wood).  Lead-acid Batteries are not really a fire risk.  (all types of lithium batteries are a fire risk because they have ~10x energy density).
The Charge controller to battery hookup has clips for this reason.
#1 measure new battery voltage (should be between 9 and 12 volts, but not necessary).
#2 remove clips from existing batteries and attach to new battery (battery should be at least 30#s).
#3 measure new battery voltage (do this during the day).  Within 10 min battery should be between 9 and 12 volts.  If battery is not quickly moving to 9 volts you may have a problem.
#4 Everything should work right away, but avoid placing heavy loads, and night use
#5 Every evening and morning check the battery voltage to get a feel for self-discharge and capacity.

Loads
The charge controller is a 42v 30A device.
That means that if any circuit goes over 42v and/or 30A, at least that part and likely everything fails.

So voltage open circuit (VOC) of the solar panels should be less than 42 volts.