"Larry Jaques" wrote in message
...
On Sun, 5 Nov 2017 18:52:52 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
. ..
On Sun, 05 Nov 2017 07:37:28 -0800, Larry Jaques
wrote:

On Sun, 5 Nov 2017 08:09:56 -0500, "Jim Wilkins"
wrote:

from a small system. My DPS5015 switching regulator can be used
to
find and charge at the maximum power point but it won't track
changes
automatically.

Interesting, but sort of a moot point without automation. Or is
it?
Finding the MPP of the system might be good for a boost, even
without
the tracking, but I haven't seen any studies on that. I'll look
for
some more articles on MPP to see.

Nope. Conditions vary so much that a single snapshot of an MPP in
time wouldn't be of much use. It appears that the MPPT controller
changes the resistance of the circuit so it continues to output
max
power at all times, from 1 to 1000 times per second. (one of 84
million 400 thousand snapshots a day.

https://www.teachengineering.org/les...pveff_lesson03
(I know, k12 site, but it had the info I sought.)


http://lib.tkk.fi/Dipl/2010/urn100399.pdf

Schools can buy solar simulators now, with which they can do this
type
of experimenting. Guessing that FLC won before reading the article,
which looks like one I'll enjoy. Thanks.


Finding the MPP with the DPS5015 shows me how much more current an
MPPT controller would give, compared to a direct connection from the
panel to the battery as with a PWM controller. I've read that an
MPPT
controller isn't cost-effective for arrays of 200W or less, or for
trickle charging batteries whose voltage is already close to the
MPP.

Yup, but they can give you a whole lot more usable power on larger
systems. I intend to expand this 1kW system to 6kW at some time in
the future, so I should probably buy that Outback before more
panels.
So, with the new 100w panel, are you now only up to 145w
(theoretical)?

I have around 200W now and ordered another 200W. The limitation on
solar here is large shade trees that cut my air conditioning bill to
$5 a month. One solar array catches an opening between the trees
before noon, the other after it. I used an extra freestanding HF panel
to find a convenient area for the new panels where I can get power
from 8AM to 2PM though it's not a good spot for a permanent mount.

After the leaves fall there's sun all day, filtered somewhat by bare
branches. I already have enough solar power to keep my vehicle and
backup batteries topped off but this last storm and run time test
showed how dependent I am on a generator if I can't keep food cold
outdoors.
-jsw