[RE-wrenches] DC to DC converters

[Dan Fink]

Ray;
I've even had problems with Magnums and Outbacks not working with certain
GFCI outlets.I usually just avoid installing GFCIs in tiny, remote off-grid
systems designed for a specialty application with no electrical inspector
involved or required. GFCIs cause all kinds of mischief with equipment and
are a phantom load. I put them in the same league as hard-wired 120VAC
smoke detectors off the grid.

Exeltech inverters are certainly the most quiet RFI-wise, but the low
efficiency, $  and no-load draw are a bummer.

With William's application, I'd avoid the inverter entirely and go DC, then
you have no GFCI or AC codes. If the sat link DC input specs allow 36VDC
input, you have many off-the shelf options available for a boost/buck power
supply from 24VDC. Digikey even.

Dan Fink
Adjunct Professor of Solar Energy Technology, Ecotech Institute
IREC Certified Instructor™ for:
~ PV Installation Professional
~ Small Wind Installer
Executive Director, Buckville Energy
NABCEP Registered Continuing Education Providers™
970.672.4342



On Mon, Mar 28, 2016 at 4:47 PM, Ray Walters <ray at solarray.com> wrote:

> What about building a 30 vdc system (5 x 6v batteries in series)  and
> adjust the settings on a Midnite Classic to work with that?  How tight does
> the 30 vdc output need to be?
>
> On inverters, I've had  trouble with the Suresine, basically not working
> with GFCI outlets.
> I keep trying different models of GFCIs, but they keep randomly tripping
> on 2 different systems.
> Morningstar's list of "approved" GFCIs doesn't list any currently
> manufactured models, while calls to their tech support yields "Oh, that
> shouldn't be a problem, it should work with all GFCIs..."
> Way too many free trips out trying to fix this, so I may have to abandon
> GFCI protection, or replace the inverters.
> My suggestion for that small load: Exeltech 125.  Better than grid
> waveform, and I recently pulled one out of corroded outdoor enclosure
> almost 15 years old: it looked terrible, but was still working fine.  It
> would also be lower cost and fit in a smaller enclosure.
>
> R.Ray Walters
> CTO, Solarray, Inc
> Nabcep Certified PV Installer,
> Licensed Master Electrician
> Solar Design Engineer303 505-8760
>
> On 3/28/2016 2:24 PM, Dan Fink wrote:
>
> Hi William;
> 30VDC is kind of odd, but 36VDC is common. The folks at Solar Converters
> might be able to fix you up with a custom one, or perhaps 36V is within the
> sat unit's input range.
> As for the inverter, I've never gone wrong with the Morningstar SureSine.
> Slick little unit.
>
> Dan Fink
> Adjunct Professor of Solar Energy Technology, Ecotech Institute
> IREC Certified Instructor™ for:
> ~ PV Installation Professional
> ~ Small Wind Installer
> Executive Director, Buckville Energy
> NABCEP Registered Continuing Education Providers™
> 970.672.4342
>
>
>
> On Mon, Mar 28, 2016 at 1:44 PM, William Miller <
> <william at millersolar.com>william at millersolar.com> wrote:
>
>> Friends:
>>
>>
>>
>> I am designing a satellite data interface for a large off-grid system for
>> a state highway department facility.  We will be using the Outback Optics
>> data capabilities along with equipment manufactured by Control by Web.
>>
>>
>>
>> I’d like to run the satellite system on a battery power source so I can
>> hope to use it when we need it most, when the power is down.  We have a
>> separate 24 volt battery bank remaining from a previous generator control
>> system.  The satellite system operates on 30 VDC at 2 amps.
>>
>>
>>
>> My first choice is to find a DC to DC converter from nominal 24 volts.
>> Do any of you know of one that you could recommend?
>>
>>
>>
>> My second choice is to use a small inverter.  Can anyone suggest one at
>> this small wattage?  I don’t know how good the power supply is at rejecting
>> waveform distortion so I presume an inverter needs to be somewhat close to
>> a sine wave.
>>
>> Thanks in advance.
>>
>>
>>
>> William Miller
>>
>>
>>
>>
>>
>> [image: Gradient Cap_mini]
>> Lic 773985
>> millersolar.com <http://www.millersolar.com/>
>> 805-438-5600
>>
>>
>>
>
>
>
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