[RE-wrenches] Outback with grid charging

Sat Aug 25 12:07:26 PDT 2012

Sounds like a case of bad design, misrepresentation to the customer
and not understanding the equipment.

If they have FX3048T inverters, they cannot sell excess RE generation
(and I'm going to be gracious and set aside for a moment any
assumptions about the installation of these particular turbines, or
ability to produce RE power) to the grid.  Therefore, they either can
operate the protected loads "off-grid" by using the HBX mode to drop
the grid, cycling their batteries, and hopefully charging them from
the wind's input.  Alternately, they can put the inverters into backup
mode to protect the downstream loads from a utility outage.  That's
probably what they are doing now, as it's the default when that
inverter sees an AC input. The offgrid FX assumes the AC input is
generator, so figures if you're running a genny you don't want the
charger to go silent.  The batteries are at float, and the turbines
are producing squat -- and that's not because of tower height or
siting or turbine quality, it's because the batteries are full and the
loads are being supplied by the grid and there's nowhere to put excess
energy.

You can cycle the batteries and pray for enough RE generation to keep
the batteries charged. Or float the batteries and let the turbines be,
well, yard art.  If you can't sell the power back to the utility, the
batteries will sit in float and the RE generation will go into
regulation.  Or you can swap out the FX for GTFX inverters and sell.
The GTFX inverter has the additional advantage in it "knows" the AC
input is grid, and won't float the batteries from grid power.  That by
itself will reduce the AC consumed from the utility.  Plus, you get
the benefit of selling the great excess RE.  If you don't want to go
full-bore utility-interactive the Radian has an additional capability
to "offset" utility power with RE power and not cycle the batteries,
but it's generally better to be utility interactive whenever possible.

Mainly it sounds like a matter of figuring out what the client wants
to achieve, and then setting up the right equipment in the best way to
get that job done.  The last handful of guys didn't do that, hopefully
you will be able to help them understand this, and then make this
system right.  And get it in writing.

Best wishes for this,

Phil

On Fri, Aug 24, 2012 at 7:39 PM, Kent Osterberg <kent at coveoregon.com> wrote:
> Jesse,
>
> Sometimes the best thing you can do for a customer is document, in writing,
> what's wrong. And walk away if they aren't willing to fix it.
>
> Kent Osterberg
> Blue Mountain Solar, Inc.
> www.bluemountainsolar.com
>
> On 8/24/2012 6:36 PM, Jesse Dahl wrote:
>
> Im with you on the wisdom of it.
>
> The problem with my area is that people maybe good a grid tie, but there are
> very few people that understand the off-grid applications (DT is the only
> person I think is worth listening to.)  The contractor they chose was the
> only contractor the home owners spoke to that lacked any type of
> certification, not that that means anything.  The homeowner told them what
> they wanted to do and the contractor said okay.  Even though it was a poor
> idea.  I was shown email conversations between the two.  Of course there is
> always two sides to these stories...
>
> The system was supposed to use two wind generators to charge two battery
> banks and then feed to FX3048 Outback inverters.  Both inverters were also
> tied to the homes panelboard to help charge the bank in-case of low wind.
> The two Outbacks fed a 100A panelboard that had a few loads from the home
> wired to it (well pump, furnace, sump, various receptacles)  The panel also
> has a bypass switch that allows it to bypass the inverters all together and
> use straight grid power to run the loads.
>
> The homeowner supplied the wind and the controllers, the contractor supplied
> the inverters and electrical BOS and the 16 MK 12V batteries.  Another
> contractor came up to program the setpoints.
>
> I have mentioned jobs like this before on the list, and I keep finding them
> up here,  its getting a little old.
>
> I told them today to get both generators up to at least 80 feet or to scrap
> both a install a 4kW array.  I also said if the want to hire me, what I say
> goes and if I say it all comes out to start over, that's what happens.
>
> On Fri, Aug 24, 2012 at 12:40 PM, <toddcory at finestplanet.com> wrote:
>>
>> i am not understanding the 'wisdom' of using non-grid tie inverters in
>> this application. it is pretty easy to modify the inverters (board change
>> out) to grid tie models, which would allow the inverter's to transfer the
>> loads to the grid (internal transfer switch) and 'sleep' until there is an
>> outage to back up. the only additional use the system would bring to their
>> bill is re-floating the batteries occasionally.
>>
>> with no renewable input (except silly, yard-art wind gennys), basically
>> they have an expensive whole-house ups. i wonder what the intention or
>> original design was supposed to do?
>>
>>
>>
>> todd
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Friday, August 24, 2012 9:14am, "Jesse Dahl" <dahlsolar at gmail.com>
>> said:
>>
>> I do not want to take this on!  The wind, from what I have gathered is an
>> absolute bust.  Just doing a little online research it seems like they are
>> getting next to nothing from the wind generators.
>> From my little understanding of the system and reading replies, I would
>> say they are buying power, losing 30% of it and then powering loads.
>> This system was installed by a contractor in Duluth, MN.
>> Jesse
>>
>> Sent from my iPhone
>>
>> On Aug 24, 2012, at 10:31 AM, Kent Osterberg <kent at coveoregon.com> wrote:
>>
>> Two 1-kW wind generators doesn't sound like enough to provide energy for a
>> household except possibly in the best circumstances. If there isn't much
>> wind, the system is getting most of it's energy from the grid. The utility
>> bill would go up even if they were using the same amount of energy in the
>> house. Batteries are energy losers!
>>
>> What Dave and others have warned about kWh metering issues is also true.
>> The new digital meters have many capabilities and the default for most of
>> them is to record energy going in either direction as energy consumed. Since
>> they are programmable, the same meter can be used to record net energy -
>> behave like most disk-type meters; ignore energy in one direction - behave
>> like a detented meter; or record both incoming energy and outgoing energy
>> separately - a two register meter.
>>
>> Kent Osterberg Blue Mountain Solar, Inc. www.bluemountainsolar.com On
>> 8/24/2012 6:26 AM, Jesse Dahl wrote:
>>
>> The system only uses grid power to charge batteries, they have two FX3048T
>> in parallel so I don't think the meter is the issue.
>> They did send me a picture of the two wind towers, one is 20 feet off the
>> ground and one is 60 feet off the ground... No wind would be an
>> understatement.
>>
>>
>> Sent from my iPhone
>>
>> On Aug 24, 2012, at 7:43 AM, David Katz <dkatz at aeesolar.com> wrote:
>>
>> Check to see if their meter goes backwards.  Some utility meters actually
>> charge for power when you are selling.
>> Or maybe they have no wind and a new big flat screen tv that they leave on
>> all the time.
>> David Katz
>>
>>
>> ----- Reply message -----
>> From: "Jesse Dahl" <dahlsolar at gmail.com>
>> To: "Wrenches" <RE-wrenches at lists.re-wrenches.org>
>> Subject: [RE-wrenches] Outback with grid charging
>> Date: Thu, Aug 23, 2012 11:28 pm
>>
>>
>>
>> Hello,
>>
>> I got a call from a family today about a system they had installed
>> recently and they think they have a problem.  They claim their electric bill
>> has just about doubled since the system has been installed due to outback
>> using the grid to power the loads instead of the battery bank.  They claim
>> the MATE always shows the system buying the exact amount as any load on the
>> system draws.   Due to the distance from my shop, I would like to get any
>> ideas on what could cause this before I drive all the way there.
>>
>> What I know about the system:
>> 2 - outback inverters, 48v
>> 2 - whisper 500 wind generators with whisper charge controllers
>> 16 - MK 12v AGMS (8/inverter)
>>
>> I guessing setting, but if anyone has seen this before, I'd like to narrow
>> it down before the drive.
>>
>> Thanks eh!
>>
>> Jesse
>>
>> Sent from my iPad!!!
>> _______________________________________________
>>
>>
>>
>
>
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