Hi there, new to the NG and to solar power generation in general, have a
couple questions I hoped maybe some experienced people could advise me.
I have a 15V/75W/5A panel, are 300W/2.5A charge controller (ICP SolarPro75
& CC20) and a couple of deep cycle batteries. My original notion was to charge
one battery while a I drained the other, swap them as necessary, but I have
done a bit of reading online, and am wondering if the wiser approach would
be to hook them up in parallel, draw and recharge simultaineously. My concern
is battery longevity. My electrical consuption is quite low, only 2 to 4 Ah per
day, but I cannot mount the panel optimally (apartment dweller). On good sunny
afternoons/evenings I seem to be able to push about 1.5A for 3 or 4 hours, I'd
guess I create about 7Ah/day if you include the power generated from ambient
light in the AM & PM. Which approach to battery usage would promote longevity
in my system?
Additionally, because of my limited light supply, I am anticipating running
a power defecit during the winter. I have two speculations that could use a bit
of enlightenment. First, my panel is mounted facing westward, and there is a
white building across the alley. It seems that the light reflected off of it
in the early morning generates more power than after the sun has risen a bit.
This leads me to think that in winter, under a good blanket of snow, the
reflected light of the day will generate more power than the reflected light
of summer. Is this a reasonable thing to anticipate? Secondly, because I
believe I'll be running a defecit for a while, I have been looking at ways
to accomodate for it. Buying extra deep-cycle batteries seems to be the default
choice, but I've been looking at the NiMH that are out now. Did a little
experiment the other day, was able to run my inverter and laptop off of 10
AA NiMH in series. I then went looking for numbers on different NiMH, I have
found 1.2V D-cells with a 9000mAh rating. 11 of these in series should
produce a 99Ah 13.2V battery, if I understand correctly, and for every set
of 11 batteries I hook in parallel, I increase my Ah by 99 hours. This, to me
seems like a fine approach to making a high-capacity, physically small battery,
because I can purchase a "node" of batteries 11 at a time. If my goal was to
give myself, say, about 500Ah reserve, I could purchase the batteries as
money came available to do it. My problem with this is that I don't know if
this is a wise approach to battery-pack building, as I've read that I should
use batteries of the same relative age when they are used in parallel (although
this seems to apply to conventional deep-cycle batteries, but NiMH?), and I
also don't know if NiMH can be charged with my hardware.
Whatya think? Got a good link?
Thanks for your time...
Slackware9.0, IBM Thinkpad560 <P100, 40MRAM>
: Hi there, new to the NG and to solar power generation in general, have a
: couple questions I hoped maybe some experienced people could advise me.
: I have a 15V/75W/5A panel, are 300W/2.5A charge controller (ICP SolarPro75
: & CC20) and a couple of deep cycle batteries. My original notion was to charge
: one battery while a I drained the other, swap them as necessary,
Battery types are different, some need to be
drained completey before recharging, but lead acid
will not accept that treatment, a regular car battery
drained completely dead twice or three times should
be considered junk.
Some radio control people actually solder dead
short leads to certain types of batteries between
uses, but most low cost systems use lead-acid and
are best kept charged above 50 percent if possible.
There are gel cell deep discharge batteries
that will suffer a couple hundred deep cycles before
giving up, but even they are best kept above 40 percent.