[RE-wrenches] Sync problem

[Allan Sindelar]

Geoff,
It's never that simple, is it?

Yes, there are two settings. The charge amps setting exists to limit max
charge rate, such as for a small battery bank with C/rate limits. William's
point is that the loads can exceed this, and indeed exceed the AC in
setting.

The SW could provide true generator support, meaning that the two settings
(Set AC2 in and Set Gen amps AC) were hard limits. As the AC load increased,
the SW reduced the charge rate as needed to meet the load. If the load
continued to increase beyond the "Set AC 2 in" limit, the SW could actually
invert from the batteries to supply the load, thus supporting the generator
while it's connected and operating.

The Outback can't do this; I'm not sure if any modern inverters can. I
discussed this issue with John Pfeifer, CEO of Apollo, at SPI; his inverter
doesn't either, but he sees the value of it and will look deeper into
whether it can be designed in. Silent Power has a separate charger, and I
heard that the new Samlex does too, so this isn't an issue with those units.
The Outback can reduce charge current, but as well as I can tell, it either
is too slow or too soft a limit, and a surge can overload the generator.
This is why Steve H. has suggested sizing the generator as a rule of thumb
at 2X the AC input setting.

I would welcome further info and corrections to my understanding here.


Allan Sindelar
Allan at positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.PositiveEnergySolar.com


-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Geoff
Greenfield
Sent: Friday, October 30, 2009 1:39 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Sync problem

William - thank you for completing my thoughts... wish we had hooked up at
the show - oh well.

I believe on the Mate there are TWO amps one can play with - AC charge as
well as another "total" AC input that includes the charger as well as the
loads.  I have still popped genny breakers using this one....

For a brighter energy future,

Geoff Greenfield
President

Third Sun Solar & Wind Power Ltd.
340 West State street, Unit 25
Athens, Ohio 45701
(740) 597-3111   fax: (740)597-1548
www.third-sun.com

Clean Energy - Expertly Installed


-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of William
Miller
Sent: Friday, October 30, 2009 3:34 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Sync problem

At 12:18 PM 10/30/2009, you wrote:

Sorry, incomplete sentence in original post.  Corrected below:




Friends:

In addition to ramping down the charge amps, you also need to ensure that
the loads are removed for testing.  Even with charge amp at 1, if the
loads exceed the capabilities of the generator to maintain adequate
voltage and frequency the inverter will disconnect the generator.

I discussed this very issue with Outback at the show yesterday.  The GFX
series inverter has tighter input tolerances on the AC input than a none
grid-tie model.  This is because there is only one AC input and that input
needs to comply with grid tie requirements.

Another short coming of the Outback is: if the loads exceed the source
capabilities, once the transfer occurs, the source will overload, be it to
trip a source breaker or bog down a generator.  If this were an SW or XW
inverter, the inverter would synchronize with the source and assist in
delivering power to the loads.

William




At 12:07 PM 10/30/2009, you wrote:


Hi Drake-

You may be overloading the genny (and it either pops a reset breaker or
just shows a red light that there is an internal overload, requiring you
cycle the on/off switch to reset.

To "test" I suggests ramping down the charging AC amps on the mate to 1 or
so, see if the genny charges, then step up the charger amps until the unit
cuts out.  Kinda like the Appalachian torque wrench: tighten until the SS
bolt breaks off, then back it off 1/2 turn.

_


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