That almost has to be a custom setup. There are a couple of similar units on
the Earthwalk site, but none of them mention either a controller or an
inverter (why the DR inverter I wonder - especially for Senegal, which is
not 120v/60hz ?). http://www.uspowerco.com/anypage.php?id=58
The use of the VCS is a bit odd.
As for your batteries being down to 5 volts, they might already be dead
meat. If your controller is dead, connect the panels directly to the
batteries for a while (bypass all the other stuff in the cart) to see if the
voltage comes up at all, if you can do so with that setup without a major
rewiring job.
..................................................................................................
Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
..................................................................................................
----- Original Message -----
From: "Walt Ratterman" <wratter...@sunenergypower.com>
To: "'RE-wrenches'" <re-wrenches@lists.re-wrenches.org>
Sent: Saturday, June 27, 2009 4:28 PM
Subject: Re: [RE-wrenches] Solar Boost Controller in Senegal
Hello again,
Thanks to all of you who chimed in with suggestions and comments on this
very apparent mis-application of the Solar Boost charge controller!!
In looking at options for them, I thought of using the Morningstar 15Amp
MPPT controller. They have a cut-off of 70V DC on the Voc, and ask for an
array not to exceed 400 watts. The system here in Senegal is a whole lot
closer to meeting those criteria than the Solar Boost. (73Voc and 440
Watts/p) I have written to MS to see what they think about this.
I hope to hear from Solar Boost to see their opinion, on what the best
plan
of action could be from their perspective. Chances are, Solar Boost has
no
idea the equipment was used this way.
Some of you asked who designed this? I am not really sure, but there is a
company named Earthwalk that primarily provides laptop computer packages
for
remote education facilities. They come with a battery charger cart for
the
laptop batteries that is designed to plug in at night (especially when
there
are problems with the grid power during the day.) The Earthwalk company
provides as an "accessory" a solar charging station for locations without
the grid. They include the system I described, but with a few other
unusual
design thoughts. (They use AGM batteries instead of GEL batteries, they
have a new DR1524 inverter, and they use a Solar Converter Model VCS-2AH
switch, that I think is being used as a Low Voltage Disconnect, and I
think
that is set at 20V....) These systems were assembled very nicely into a
rolling cart in the states, and shipped to Senegal. (The 12V Dekkas are
measuring 5V now, on this end before placing into commission.)
So - it is likely that Earthwalk commissioned a "solar" company to build
this for them. I am trying to find that out now.
I just want to recommend the best action to them now instead of when all
of
the systems start failing...which I am afraid they will do very soon. I
see
enough failed systems. I would just like to stop this train wreck.
Thanks again for all your input.
From the bush in Senegal!!
Walt
-----Original Message-----
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Larry
Crutcher, Starlight Solar
Sent: Saturday, June 27, 2009 7:42 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Solar Boost Controller in Senegal
...And the Voc is present every morning before the current is high
enough to start the controller. That's when I would expect to have a
problem. boB, I doubt that the Voc sample duration is long enough to
cause a problem.
I know that Rick got back on this list a few months ago so if you
(Rick) have any input to help Walt, we welcome your comments.
Larry Crutcher
On Jun 27, 2009, at 2:35 AM, boB Gudgel wrote:
Wind-sun.com wrote:
Yes, it is a poor design. though you may not have any problems
there with the heat de-rating of the panels. If the panel
temperature gets under about 40C you may blow out the input. As
long as you have a load on the output of the contgroller, it will
keep the voltage down, but if the output is disconnected the input
could go up to full voltage.
Remember that this controller opens up every so often, (8 seconds or
so?) to check Voc and adjust the MPP-V based on that measurement.
boB
Who designed such a system?
............................................................................
......................
Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
Online Store: http://store.solar-electric.com/
Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
............................................................................
......................
----- Original Message -----
*From:* Walt Ratterman <mailto:wratter...@sunenergypower.com>
*To:* 'RE-wrenches' <mailto:re-wrenches@lists.re-wrenches.org>
*Sent:* Friday, June 26, 2009 3:22 PM
*Subject:* [RE-wrenches] Solar Boost Controller in Senegal
Hello,
I am in a very remote part of Senegal, (near the Guinea and Mali
borders.) and I have come across some prefabricated "plug and
play" American made systems installed for educational institutions.
The systems use two Sharp panels that are 220Watts, 33.6 Voc, 29.2
Vmp, wired in series, using #10AWG home run wire from the panels
back to the charge controller.
Charge Controller is a Solar Boost 50.
Batteries are Dekka AGM - two strings of 250AH, 12V
batteries. (four batteries total).
My specific question is about the controller. This is a 24V in /
24V out charge controller with MPPT. I have not used this before,
so I am not familiar with the details of operation.
The data sheet that I downloaded says that the maximum open
circuit voltage is 57 VDC. But, this system is hitting the charge
controller with two panels of 33.6 VDC wired in series for
73.2VDC. So, why is the controller not fried, or what am I seeing
wrong here. I suppose with the panel temperature being elevated
maybe 35 degrees above 25 degrees and a resulting 17.5% loss,
coupled with some voltage drop, the system may actually be seeing
less than the 57 volts...
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