Larry, Pitfalls ?
The biggest pitfall I would say is if you have a VERY stiff grid.
If your Voc is say, 170V DC and the CC current limits it output at say,
169 V DC,
they you are going to need to add an input power resistor of a couple
Ohms to
help cushion the input to be more like a PV module. A lot of times, the
grid is
not nearly this bad, especially generators.
Also, If you are going to do this, I would NOT use Solar mode but
instead try
Hydro mode set to Manual MPP voltage. First start the MPPV at something
just
less than Voc or maybe, say, 160 VDC. Then, from main STATUS screen,
you can
adjust the input voltage up and down by pressing the Soft-Right or Soft-Left
keys respectfully. (upper right and upper left keys). Then you can
manually get
a feel for what it should be set for.
The Classic 200 is the only CC of ours that I would use. The 250 would
work but the
200 is much more suited. I wish there were a real charger that one
could buy that was
isolated, and we have never really advocated MPPT charge controllers for
this but
in a pinch, they always seem to work find. Never did add a "DT" mode
(after Daryl
Thayer of course), but this hydro mode seems to work OK.
If you want to let it sweep but setting it to 3 minutes (or higher) that
will also work.
If you do that, set the minimum input voltage. Something like 140V or
so will keep
it from dropping the input voltage too low and either bogging down the
input source
and the rectifier bridge (especially generators)
You can also set the INPUT current limit in the LIMITS menu. This was
for hydro
in particular. Either limit can help reduce Isc or bogging down issues.
The other pitfall is that it is NOT galvanically isolated so you should
be very careful.
We use an X240 equivalent transformer to keep the batteries going in our
burn in
rack using 2 Classic 200s and it works great.
Also, use a nice and strong full bridge rectifier so that it applies 120
Hz instead of
60 Hz to the input. That is much easier on the input capacitors and
things and just
makes it work smoother. There are input capacitors (filtering) on most
charge controllers.
Again, in a pinch this seems to work but watch that input max power
point voltage to make
sure it is not too high compared to the Voc. If there isn't enough
voltage spacing between
the two (stiff AC source) then the control isn't going to be very smooth
and might risk
letting the smoke out.
What ever you do here, be very careful what you touch !
boB
On 12/16/2014 6:39 AM, Larry wrote:
I must have missed the prior discussion about using PV CC. The concept
sounds good but how many of you have done this and are there any
pitfalls to be aware of? If I use a 20 amp bridge I should be able to
produce 80 amps @ 14.4V. For continuous operation, will I need a large
heat sink on it?
How does the unfiltered full wave peak voltage affect the CC over
time? Are they (specifically Midnite) really designed to handle input
waveform like this? I like this idea, especially if I can stack the
controllers.
Thank you,
Larry
On 12/15/14 6:51 PM, jay peltz wrote:
Hi Kirk,
If you use a 200vdc midnight CC you'll have no issues.
When you rectify 120vac its up around 166vdc
( uses the peak vac which is around 170vac.)
For a 150vdc max controller ( midnite 150) or a 144vdc ( outback FM)
then a buck transformer or standard transformer is the trick to
reduce the AC and hence the DC for these lower voltage units.
jay
peltz power
On Dec 15, 2014, at 5:38 PM, Kirk Herander wrote:
This has been discussed on this list in years past. It is possible
to use an outback charge controller as a battery charger. You need
to put the 120 AC into a bridge rectifier, then feed the 120 DC into
the controller's PV input. So you'll have an 80 amp battery charger.
*Kirk Herander*
*VT Solar, LLC*
*/Proven PV provider since 1991/*
*www.vermontsolarnow.com*
dba Vermont Solar Engineering
NABCEP^TMInaugural Certificant
VT RE Incentive Program Partner
802.863.1202
*From:*RE-wrenches
[mailto:re-wrenches-boun...@lists.re-wrenches.org]*On Behalf Of*Dan
Tittmann
*Sent:*Monday, December 15, 2014 8:18 PM
*To:*i...@windsine.org <mailto:i...@windsine.org>; RE-wrenches
*Subject:*Re: [RE-wrenches] Programmable Battery Charger
You can manually adjust Iotas with tweaking the potentiomiters while
monitoring it with a god volt meter. But no time adjustment.
Daniel
Daniel Tittmann
CTO
Greenwired
www.greenwired.com <http://www.greenwired.com>
dan...@greenwired.com <mailto:dan...@greenwired.com>
707-923-2001 (office)
707-206-5088 (Cell)
On Mon, Dec 15, 2014 at 4:21 PM, Windsine Inc. <winds...@gmail.com
<mailto:winds...@gmail.com>> wrote:
Check out Argus Technologies.
RoyR
On Dec 15, 2014 4:01 PM, "Larry" <la...@starlightsolar.com
<mailto:la...@starlightsolar.com>> wrote:
Wrenches,
Does anyone know of a 120/12 volt battery charger that can be
programmed for absorb and float voltage and time in absorb mode? I
have been needing this product for many years but I can only find it
in inverters with built in chargers from Magnum, Outback, and Xantrex.
--
Thank you,
Larry Crutcher
Starlight Solar Power Systems
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