[RE-wrenches] Solar Boost Controller in Senegal

Sun Jun 28 13:05:56 PDT 2009

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" <wratterman at sunenergypower.com>
To: "'RE-wrenches'" <re-wrenches at 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-bounces at lists.re-wrenches.org
> [mailto:re-wrenches-bounces at 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:wratterman at sunenergypower.com>
>>>   *To:* 'RE-wrenches' <mailto:re-wrenches at 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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