Thursday, March 5, 2015

Regarding Solar Options


Being that I have been off-grid for the last five years and built
several small to large solar systems, I thought I would pass on what I
have learned.

First, Goal Zero does make some quality stuff....never had any
noteworthy problems with them. That being said - if you are going to go
with their Yeti 1250, do yourself a favor and skip the Goal Zero Boulder
panels and order a full sized 240-250 watt (mono or poly) solar panel.
It's a lot more bang for your buck and 250 watts is about the max the
Yeti's internal charge controller can handle. You would need to also get
the MC4-to-anderson power pole converter cord (goal zero sells this
item, but you have to call them) and enough MC4 (10awg) cord to support
your setup. It's worth mentioning that you can also add a second battery
and double the storage capacity of the Yeti 1250, giving you around 2500
watts of power. You need to make sure and match the internal battery of
the yeti which is a 12v 100ah SLA/AGM (can be found at your local
Batteries Plus store or ordered on Amazon, but shipping will hurt).

Second, if you want to try and roll-your-own, I would highly encourage
the use of AGM batteries as opposed to flooded lead acid as another
commenter had mentioned. Flooded Lead Acid are a better value money
wise, but present several problems that preclude them from serious
consideration, especially if you have mobility in mind. Compared to FLA
batteries, SLA/AGM (Sealed Lead Acid/ Absorbed Glass Mat) batteries are
sealed and do not appreciably off gas hydrogen, making them much safer
for enclosed living areas. They also can tolerate being turned on their
side and are more tolerant of temperature extremes. They do, however,
cost a bit more than FLA's, but due to the factors mentioned, they are
all I use in my own projects.

A simple setup (comparable to the Yeti above) would be to purchase the
following items:

1. 12volt / 100ah SLA/AGM battery

2. 100 watt folding solar panel

3. 10amp, 12/24 volt MPPT charge controller (might go with a 20 or 30
amp for future upgrades)

4. Medium size rolling toolbox ("dolly" style)

5. 1000watt AC/DC inverter

6. 10awg cables w connectors for your chosen panel, 8awg cables for
internals

7. automotive/ blade style fuse holders and fuses (match the amps of the
chosen charge controller)

8. Optional - NOCO wicked smart battery charger (if you want to top it
off when you have access to the grid or a generator.


Start by securing battery in the bottom of your "toolbox" housing, then
mount the inverter and charge controller inside, making sure that they
all have space between them and room for airflow as cooling is
important. Connect the cables that run between the panel and the charge
controller to the CC adding one of the in-line fuse holders to the
positive cable. Run a set of the 8awg cables to the battery (leave the
positive disconnected for now). Run a set of 8awg cables from either the
battery or the CC, depending on the model, to the inverter (inverter
should have it's own fuses). Connect the solar panel to the first cables
you set up, make sure all your fuses are in place and connect the
positive battery cable. The CC should read the state of the battery and
begin charging or maintaining the battery.
This setup will give you the same 1200 watt rating that the Yeti 1250
has out of the box for about half the price. If you wish to use the NOCO
charger, you would just attach its alligator clips to the battery, plug
it into a 120AC wall socket, select the appropriate voltage and battery
type on it's faceplate and you are in business.


A quick note regarding inverters. There are two basic types of inverters:

- Pure sine wave (more expensive)

- Modified sine wave (less expensive)

Besides the cost consideration, care must be taken as a modified sine
wave inverter can cause problems with more sensitive electronics, such
as computers. I don't know if modified sine wave would present problems
for the charging or powering of radio equipment - perhaps Sparks or Dan
can chime in here?


***

Another option would be to purchase a small folding 14-16watt panel and
a lithium/ion battery pack for use in the charging of phones, tablets
and other handhelds in the field. This style of battery pack has come a
long way and 12000mah - 30000mah units can be found on Amazon with ease.
This is a power solution I will be offering for my tablet project as well.


While this has been a rather breviloquent guide to setting up a solar
system and there is obviously much more info available on the subject,
this should get you started on the right path. If there is more interest
from the readership I can put together a more detailed post on the setup
or possibly just build and ship them for those that want that.




2 comments:

  1. solar power system such as a good things for humans, it helps in many thing like charging and many other thing...

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  2. I'd be interested in hearing more. I've been mulling over the concept of a couple of banks of batteries mounted along each side of my truck bed, rigged to dash switches to toggle them between a parallel connection to the truck's electrical system and a solar panel array on the camper shell roof. Among other things this would greatly expand the utility of my mini truck fridge, with the ability to leave one bank offline in reserve for starting the truck.

    Aside from mere procrastination over the financial outlay, I'd been stuck on the metal fabrication necessary to shield them from the flotsam and jetsam in my truck bed. Don't know why I didn't think of just modifying a couple of steel toolboxes before (or ammo cans oooh time to go measure out my 25mm and 30mm cans in the garage). Anyway, duh thanks.

    My remaining puzzle is the rigging of some 12V PC case fans to cool the toolboxes when the banks are charging or discharging. I suppose I could shell out a little more for a charge controller with an extra circuit just to run the fans, but that still wouldn't help me during discharge. I'm sure there's something cheap and simple out there that would to light up a low-amp signalling circuit on current flow...

    Thanks for getting my gears turning again on this. I'm definitely up for reading any further thoughts you care to share on this general topic. Known makes and models to look for (or avoid!) are always welcome.

    Happy trails,

    #OREGON HOBO#

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