[RE-wrenches] Heinz 57 off-grid array

Bob Clark bclark at solar-wind.us
Wed May 5 23:11:39 PDT 2010


Wrenches:

 

Thanks for all of your good feedback.  I will be discussing the situation
with our customer.  I will let you know what the resolution is.

 

Bob Clark

SolarWind Energy Systems, LLC

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of bob
Sent: Tuesday, May 04, 2010 2:56 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Heinz 57 off-grid array

 

You might want to plan on the 2 hp pump having a starting load of about 7 X
the running load. 

That’s what I see on water pumps frequently, just for an instant, but it is
there. The pump will always be starting under a “load” so to speak. 

 

Bob

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Dana
Sent: Monday, May 03, 2010 10:22 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] Heinz 57 off-grid array

 

I see several challenges here:

·        You sure do not want both pumps on at the same time or total shut
down will result.

·        The 2HP pump is 24 amps at 120VAC or 12 amps at 230 VAC, either way
2.7KW continuous draw and start up surge at 2-4 times [5.4KW – 10.8KW]that?

This will be more than a light dimmer.

 

I think the mix and match was just covered here with compromises in the
assorted modules.

 

I s there a backup generator? Could this grinder and water pump go direct to
that on a pressure or float switch start?

 

If you are a code compliant installer then you probably are faced with a
start over.

 

I have a client that we are doing just that right now and they are glad to
do this. The 2 – 30 watt PV modules just will not get them and 2 laptops
through the winter any more


 

Thanks,  Dana Orzel

 

Great Solar Works, Inc

E - dana at solarwork.com

V - 970.626.5253

F - 970.626.4140

C - 970.209.4076

web - www.solarwork.com

Responsible Technologies for Responsible People since 1988"

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Bob Clark
Sent: Sunday, May 02, 2010 2:29 PM
To: re-wrenches at lists.re-wrenches.org
Subject: [RE-wrenches] Heinz 57 off-grid array - What should I do with the
solar modules?

 

Wrenches:

 

We were called to assess the status of an off-grid system that is not the
worst I have seen, but it comes close.

 

I have some preliminary thoughts about system redesign, but would like to
hear from the Wrenches about the array.

 

Givens:

We will not install anything unless it is to code.  It is obvious that none
of the existing system was installed to code.

We will use the existing 24V battery bank consisting of 8, Trojan L16s.  The
batteries are still “relatively fresh.”

Pump is a Franklin pump ½ hp 115VAC.  The CFs dim when the pump starts.

New load will be a GRINDER PUMP FOR SEPTIC = 2HP, 15amp (240 or 120VAC –
more than likely it will be 240V pump) – Another light dimmer!

Modest daily electrical load (estimate no more than 600 WHr/day; 25AHr) –
they are very good at managing their electrical use.

 

Solar array – to keep or replace?

8 solar modules – a Heinz 57 mix of older modules - 2 Photowatt PMX500 (Are
these modules UL listed?  There did not appear to be a rating label on the
back.) wired in series, 2 Kyocera KC120-1 wired in series, 2 Golden Genesis
PV-75 wired in series, 2 Photowatt PW 1000 12V-24V internally wired for 24V
wired in parallel with the other modules strings – all of these modules are
wired in 5 parallel strings for approximately 34.2Vmp and 20.4Imp, ~695W
(STC).   Oh, and they need a new mounting structures for the modules.

 

Should I try to work with these modules or advise the customer to start over
(any modules that are not UL listed will have to go)?

 

What is a good “rule of thumb” for a ratio of PV watts to battery bank
capacity per day of autonomy?

 

Thanks for your ideas.

 

Bob Clark

SolarWind Energy Systems, LLC

 

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