center tap and SC voltage converter [RE-wrenches]

Geoff Greenfield Geoff at Third-Sun.Com
Fri Jul 21 13:04:38 PDT 2006


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I have done it both ways with the SC units - no probs yet - new ones seem to
have internal fusing, otherwise budget for fuse/breaker requirements.

Either approach works - center tap and equalization allows unlimited
amps/surge for load (buy smallest unit), BUT dedicated "DC transformer"
approach allows your system metering to catch the load.  If you want the
trimetric amps and cumulative AH meter to be accurate it will not see the
center tapped load correctly.

For a brighter energy future,

Geoff Greenfield
NABCEP Certified Energy Practitioner

THIRD SUN SOLAR & WIND POWER Ltd.
340 West State Street
Athens, OH 45701

www.third-sun.com
(740) 597-3111

-----Original Message-----
From: RE-wrenches at topica.com [mailto:RE-wrenches at topica.com]
Sent: Friday, July 21, 2006 7:03 AM
To: RE-wrenches at topica.com
Subject: Digest for RE-wrenches at topica.com, issue 2143


-- Topica Digest --

	RE: 2005 code question
	By Damian at thesolarcenter.com

	SunFrost Voltage Upgrade question
	By allan at positiveenergysolar.com

	RE: SunFrost Voltage Upgrade question
	By cfreitas at outbackpower.com

	Re: SunFrost Voltage Upgrade question
	By info at es-ee.com

	RE: SunFrost Voltage Upgrade question
	By cfreitas at outbackpower.com

	Re: SunFrost Voltage Upgrade question
	By allan at positiveenergysolar.com

	Re: SunFrost Voltage Upgrade question
	By michael.welch at homepower.com

	Re: SunFrost Voltage Upgrade question
	By ian.woofenden at homepower.com

	RE: SunFrost Voltage Upgrade question
	By allsolar at ris.net

------------------------------------------------------------

Date: Thu, 20 Jul 2006 08:28:29 -0400
From: "Damian de Caires" <Damian at thesolarcenter.com>
Subject: RE: 2005 code question [RE-wrenches]



If your area has not yet adopted the 2005 you need to get approval from
your local inspector because in the 03 code a disconnect is required in
attic and a permanent staircase must be provided to attic, and I asked
John Wiles if a fold down staircase was applicable and he said no it has
to be a fixed permanent staircase.  If you are running through a
building I suggest metal raceway and dc fusing in attic so that there is
no unprotected high voltage dc lines in building.  But in your case I
would say use the permanent staircase argument with the architect I've
used it before and customers back down really quickly when they hear
that.

-----Original Message-----
From: Bob-O Schultze, Electron Connection
[mailto:econnect at snowcrest.net]
Sent: Thursday, July 20, 2006 12:24 AM
To: RE-wrenches at topica.com
Subject: Re: 2005 code question [RE-wrenches]

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On Jul 18, 2006, at 8:48 PM, Jeff Yago wrote:

> Your free subscription is supported by today's sponsor:
> -------------------------------------------------------------------
> Get up to 4 No-risk mortgage quotes - No SSN needed
> Competitive rates from the nation's top lenders in minutes
> Lower your mortgage payments by up to $303/month!
> http://click.topica.com/caaeYi1bz8Qcsbz9JR3a/ BestLenderFinder
> -------------------------------------------------------------------
>
> Installing higher voltage array grid tie system.  Normally we route
> from fused array combiner to inverter down outside wall to exterior
> dis-connect (no fuses), then to interior inverter(s).   Client's
> architect vetoed exterior conduit and wants to route through roof
> and down inside exterior wall to above described exterior dis-
> connects at ground level.
>
> We have been designing to 2005 code although this county still
> using older code.  New section 690.31 (E)  "Where direct-current pv
> output circuits are run inside a building, they shall be contained
> in metallic raceways from point of penetration to first accessible
> dis-connect."
>
> also,
>
> Section 690.14 (C) 5. Grouping. "The pv dis-connecting meansshall
> be grouped other dis-connecting means....."
>
> Question - Does this require Intermediate Threaded Metal Conduit or
> is EMT allowed?
No problem
> How about conduit above roof line?
No problem as long as you support it correctly
>
> Question - I think inspector may ask us to move the DC array dis-
> connect from back of house to side where meter base and AC dis-
> connect are located due to above.  Does this mean up to 6 array dis-
> connects shall be grouped together, or ALL power source dis-
> connects to house grouped together?
Here in Oregon, we are required to put an ac disconnect for the PV
system within 10' of the meter. An archaic, redundant rule as UL and
IEEE require the inverter to power down in an outage, linemen working
on the feeders would either pull the feeder fuse or ground the lines
in any case and just ignore it anyway, but there it is.
However, even in the worse case, just put in a second ac disco. One
at the output of the inverter and one near the meter. $35.00 or so.
Big deal. That way you keep the DC and ac discos at the inverter
where they belong.
Bob-O
>
> Thanks,
> Jeff Yago
>
>
>
>
> _____________________________________________________________
> Netscape.  Just the Net You Need.
>
>
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>
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>
> Moderator: michael.welch at homepower.com
>


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------------------------------

Date: Thu, 20 Jul 2006 12:06:53 -0600
From: "Allan Sindelar" <allan at positiveenergysolar.com>
Subject: SunFrost Voltage Upgrade question



Esteemed Wrenches,
We are upgrading the 12V PV power system of a 1995-era tire house, as the
original U2512SB inverter has failed and Xantrex doesn't support it. We are
raising nominal system voltage to 24V in order to accommodate future system
expansion for new owners. The home includes a 12V DC Sun Frost RF16
fridge/freezer.

What has proven to be a reliable and simple means of running the Sun Frost
off of 24V? I am assuming that I will use a Solar Converters 12/24 20A
converter, which has proven reliable in our experience for other
applications. I don't think we have ever used it on a Sun Frost, and I am
looking for others' experiences. We have also never had a failure with ICT
DC converters.

The batteries are currently to become a single string of L16s (the former
owners brought in grid for backup charging), with eventual plans to increase
battery capacity when these reach end-of-life. I could center-tap off the
bank, as Steve Willey used to suggest, but have not done so, and this will
be the only 12V load.

Your advice is much appreciated.

Allan at Positive Energy



------------------------------

Date: Thu, 20 Jul 2006 12:42:00 -0700
From: "Christopher Freitas" <cfreitas at outbackpower.com>
Subject: RE: SunFrost Voltage Upgrade question [RE-wrenches]



I think all of the SunFrosts are 12/24 vdc compatible - it's a feature
of the Danfoss compressors the they use on them.

You might give Larry at Sunfrost a call.

Christopher Freitas
OutBack Power Systems


-----Original Message-----
From: Allan Sindelar [mailto:allan at positiveenergysolar.com]
Sent: Thursday, July 20, 2006 11:07 AM
To: New wrenches posting
Subject: SunFrost Voltage Upgrade question [RE-wrenches]

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Esteemed Wrenches,
We are upgrading the 12V PV power system of a 1995-era tire house, as
the
original U2512SB inverter has failed and Xantrex doesn't support it. We
are
raising nominal system voltage to 24V in order to accommodate future
system
expansion for new owners. The home includes a 12V DC Sun Frost RF16
fridge/freezer.

What has proven to be a reliable and simple means of running the Sun
Frost
off of 24V? I am assuming that I will use a Solar Converters 12/24 20A
converter, which has proven reliable in our experience for other
applications. I don't think we have ever used it on a Sun Frost, and I
am
looking for others' experiences. We have also never had a failure with
ICT
DC converters.

The batteries are currently to become a single string of L16s (the
former
owners brought in grid for backup charging), with eventual plans to
increase
battery capacity when these reach end-of-life. I could center-tap off
the
bank, as Steve Willey used to suggest, but have not done so, and this
will
be the only 12V load.

Your advice is much appreciated.

Allan at Positive Energy


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------------------------------

Date: Thu, 20 Jul 2006 12:34:37 -0700
From: Kurt Albershardt <info at es-ee.com>
Subject: Re: SunFrost Voltage Upgrade question [RE-wrenches]



--On Thursday, July 20, 2006 12:06 PM -0600 Allan Sindelar
<allan at positiveenergysolar.com> wrote:
>
> We are upgrading the 12V PV power system of a 1995-era tire house, as the
> original U2512SB inverter has failed and Xantrex doesn't support it. We
are
> raising nominal system voltage to 24V in order to accommodate future
system
> expansion for new owners. The home includes a 12V DC Sun Frost RF16
> fridge/freezer.
>
> What has proven to be a reliable and simple means of running the Sun Frost
> off of 24V?


Does it use one of the Danfoss hermetic compressors with the external power
module?  If so, upi're in luck -- just swap the old 12V power module for a
24V one or the new dual voltage
version<http://www.rparts.com/Catalog/Major_Components/compressors/Danfoss/d
anfoss.asp>









.


------------------------------

Date: Thu, 20 Jul 2006 20:00:21 +0000
From: Christopher Freitas  --- OutBack Power <cfreitas at outbackpower.com>
Subject: RE: SunFrost Voltage Upgrade question



That is a great link Kurt - lots of info on the Danfoss compressors -
but there is one scary note at the very bottom:

------------------------------------------------------

Danfoss Power Modules For Older (4-Pin) Compressors.

Feb. 19, 2003 - Danfoss has discontinued production of all 4-pin
modules.  Owners of older 4-pin compressors will need to replace both
the module and compressor with either the BD35F or BD50 above.

------------------------------------------------------

Not sure if Sunfrost used this module or not - I suspect that it is
possible because of the number of years they have built fridges...

> Does it use one of the Danfoss hermetic compressors with the external
> power module?  If so, upi're in luck -- just swap the old 12V power
> module for a 24V one or the new dual voltage
>
version<http://www.rparts.com/Catalog/Major_Components/compressors/Danfoss/d
anfoss.asp>
>

Christopher Freitas
OutBack Power Systems, Inc.
cfreitas @ outbackpower.com
www.outbackpower.com
Arlington WA USA
Tel 360 435 6030


------------------------------

Date: Thu, 20 Jul 2006 16:03:12 -0600
From: "Allan Sindelar" <allan at positiveenergysolar.com>
Subject: Re: SunFrost Voltage Upgrade question [RE-wrenches]



Here is followup on the Danfoss compressors. I spoke with Larry at Sun
Frost. Units built within the last 3 or 4 years have the switchable voltage,
12/24. Units built before this time are fixed voltage. Switching both
compressor and power module would be required and would be very expensive.
So Larry recommends a DC converter. He further says worst case on a
two-compressor RF16 would be one compressor starting (15A) and one running
(5A), thus requiring a converter of 20A capacity.

So we are back to my original question (with appreciation for the good new
info so far): whose DC converter have you used with good success?

Thanks again,
Allan @+E

----- Original Message -----
From: "Christopher Freitas --- OutBack Power" <cfreitas at outbackpower.com>

That is a great link Kurt - lots of info on the Danfoss compressors -
but there is one scary note at the very bottom:

------------------------------------------------------

Danfoss Power Modules For Older (4-Pin) Compressors.

Feb. 19, 2003 - Danfoss has discontinued production of all 4-pin
modules.  Owners of older 4-pin compressors will need to replace both
the module and compressor with either the BD35F or BD50 above.

------------------------------------------------------

Not sure if Sunfrost used this module or not - I suspect that it is
possible because of the number of years they have built fridges...

> Does it use one of the Danfoss hermetic compressors with the external
> power module?  If so, upi're in luck -- just swap the old 12V power
> module for a 24V one or the new dual voltage
>
version<http://www.rparts.com/Catalog/Major_Components/compressors/Danfoss/d
anfoss.asp>
>




------------------------------

Date: Thu, 20 Jul 2006 15:18:55 -0700
From: Michael Welch <michael.welch at homepower.com>
Subject: Re: SunFrost Voltage Upgrade question [RE-wrenches]



Hi Allan.

You mentioned a center tap. A long time ago, I helped set up a system for a
local nonprofit that had 24 V batteries and 12 V loads. We used a Vanner
Equalizer to tap 12 V off the bank. What it does is monitor the tapped 12 V
side, and when it sees lower voltage on that side, transfers energy from the
untapped side.

I have not heard of these units in a long time, so checked and the web site
and they are still there, www.vanner.com

I suppose a DC-DC converter might be a more efficient, but the 20 A
Equalizer advertises >92%, which is not horrible.

Allan Sindelar wrote at 03:03 PM 07/20/2006:

>Here is followup on the Danfoss compressors. I spoke with Larry at Sun
>Frost. Units built within the last 3 or 4 years have the switchable
voltage,
>12/24. Units built before this time are fixed voltage. Switching both
>compressor and power module would be required and would be very expensive.
>So Larry recommends a DC converter. He further says worst case on a
>two-compressor RF16 would be one compressor starting (15A) and one running
>(5A), thus requiring a converter of 20A capacity.
>
>So we are back to my original question (with appreciation for the good new
>info so far): whose DC converter have you used with good success?
>
>Thanks again,
>Allan @+E


------------------------

Michael Welch
Submissions Coordinator
Sr. Research Editor
     Home Power magazine
     www.homepower.com



------------------------------

Date: Thu, 20 Jul 2006 18:06:36 -0700
From: Ian Woofenden <ian.woofenden at homepower.com>
Subject: Re: SunFrost Voltage Upgrade question [RE-wrenches]




I've been using a Vanner equalizer to tap 12 V from our 24 V battery
for about 20 years. I wish I knew the efficiency. I do know that it
works, and that the equipment lasts.

Ian


>Hi Allan.
>
>You mentioned a center tap. A long time ago, I helped set up a
>system for a local nonprofit that had 24 V batteries and 12 V loads.
>We used a Vanner Equalizer to tap 12 V off the bank. What it does is
>monitor the tapped 12 V side, and when it sees lower voltage on that
>side, transfers energy from the untapped side.
>
>I have not heard of these units in a long time, so checked and the
>web site and they are still there, www.vanner.com
>
>I suppose a DC-DC converter might be a more efficient, but the 20 A
>Equalizer advertises >92%, which is not horrible.
>
>Allan Sindelar wrote at 03:03 PM 07/20/2006:
>
>>Here is followup on the Danfoss compressors. I spoke with Larry at Sun
>>Frost. Units built within the last 3 or 4 years have the switchable
voltage,
>>12/24. Units built before this time are fixed voltage. Switching both
>>compressor and power module would be required and would be very expensive.
>>So Larry recommends a DC converter. He further says worst case on a
>>two-compressor RF16 would be one compressor starting (15A) and one running
>>(5A), thus requiring a converter of 20A capacity.
>>
>>So we are back to my original question (with appreciation for the good new
>>info so far): whose DC converter have you used with good success?
>>
>>Thanks again,
>  >Allan @+E


--

Ian Woofenden <ian.woofenden at homepower.com>, Senior Editor
Home Power magazine; Subscriptions: $22.50 per year, PO Box 520,
Ashland, OR 97520 USA
800-707-6585 (US), 541-512-0220, or download free sample issue at
<http://www.homepower.com>


------------------------------

Date: Fri, 21 Jul 2006 03:27:52 +0000
From: Jeremy Rodriguez <allsolar at ris.net>
Subject: RE: SunFrost Voltage Upgrade question



I have used the Solar Converters product to power a Sunfrost from a 48v
battery bank. Works great. On a side note, I tapped from two of the L16
for about a month for temp power and had to replace those two batteries.
I did not think it would damage them that quick.

Jeremy
All Solar

Ian Woofenden wrote:
>
>
> I've been using a Vanner equalizer to tap 12 V from our 24 V battery
> for about 20 years. I wish I knew the efficiency. I do know that it
> works, and that the equipment lasts.
>
> Ian
>
>
> >Hi Allan.
> >
> >You mentioned a center tap. A long time ago, I helped set up a
> >system for a local nonprofit that had 24 V batteries and 12 V loads.
> >We used a Vanner Equalizer to tap 12 V off the bank. What it does is
> >monitor the tapped 12 V side, and when it sees lower voltage on that
> >side, transfers energy from the untapped side.
> >
> >I have not heard of these units in a long time, so checked and the
> >web site and they are still there, www.vanner.com
> >
> >I suppose a DC-DC converter might be a more efficient, but the 20 A
> >Equalizer advertises >92%, which is not horrible.
> >
> >Allan Sindelar wrote at 03:03 PM 07/20/2006:
> >
> >>Here is followup on the Danfoss compressors. I spoke with Larry at Sun
> >>Frost. Units built within the last 3 or 4 years have the switchable
> >>voltage,
> >>12/24. Units built before this time are fixed voltage. Switching both
> >>compressor and power module would be required and would be very
> >>expensive.
> >>So Larry recommends a DC converter. He further says worst case on a
> >>two-compressor RF16 would be one compressor starting (15A) and one
> >>running
> >>(5A), thus requiring a converter of 20A capacity.
> >>
> >>So we are back to my original question (with appreciation for the good
> >>new
> >>info so far): whose DC converter have you used with good success?
> >>
> >>Thanks again,
> >  >Allan @+E
>
>
> --
>
> Ian Woofenden <ian.woofenden at homepower.com>, Senior Editor
> Home Power magazine; Subscriptions: $22.50 per year, PO Box 520,
> Ashland, OR 97520 USA
> 800-707-6585 (US), 541-512-0220, or download free sample issue at
> <http://www.homepower.com>


------------------------------



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