[RE-wrenches] Advice needed on upsizing a battery & grid interactive inverter stack

Sun Aug 8 07:39:08 PDT 2010

Can the Outbacks be mixed as ½ or whatever number be GT units and the rest
be off grid so they can charge off a generator or better than that make the
battery charging inverters Magnums, they give more charge for the bucks.
They can feed a load panel on their own and charge the batteries off the
generator when need be. I see no reason they could not be all hooked to the
same battery bank but it better be huge (needless to say)!

Zantrex used to make a unit called “incharge” that I have used several
times. It hooks to an alternator and gives you 3 stage charging. They worked
quite well but I HATED setting them up. They have a set of magnetic switches
in the potting that you had to activate to adjust, in sequence or go back to
the start and do it again.

I absolutely hated the god forsaken things every time that I had to get near
them, but if you can deal with the adjustments they worked well. Needless to
say I would have liked knobs much better!

Later,

Bob Ellison

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mick Abraham
Sent: Saturday, August 07, 2010 7:14 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Advice needed on upsizing a battery & grid
interactive inverter stack

Thanks for the input, Daryl~ For now the prospect is considering sufficient
power for a big energy hog home plus outbuildings. They'll probably get over
that soon once the sticker shock sinks in. You asked, "how big a battery
bank and how big a generator?" Mick replies: the whole hog system would
need...guessing...about 500 kilowatt-hours of storage (~14,000 amp hours at
48 volts), 70kW worth of inverter/charger, plus a lot of PV. A 48 volt
generator seems not best because that would involve over 1,000 amps coming
off the machine. Maybe multiple DC generators would be worth consideration.
I see why you are pointing in that direction, Daryl, because if not for the
generator problem the Outback GT system can go large.

Finding a 48 volt generator line with proper end of charge regulation is
another challenge. Can any List member provide feedback on the Canadian mfr,
Mechron?

Much appreciated, 

Mick Abraham, Proprietor
www.abrahamsolar.com

Voice: 970-731-4675

On Sat, Aug 7, 2010 at 11:19 AM, Darryl Thayer <daryl_solar at yahoo.com>
wrote:

I have a functioning Outback system of 12 inverters, the original design was
for 15 inverters. My system can sell up to 40 kW to the grid and I have seen
pictures of systems up to 25 inverters.  How big a battery bank and how big
a generator?  Realistically you may not want to charge over C/10    Have you
considered a 48 volt generator?  

Daryl 

--- On Fri, 8/6/10, Mick Abraham <mick at abrahamsolar.com> wrote:

From: Mick Abraham <mick at abrahamsolar.com>
Subject: [RE-wrenches] Advice needed on upsizing a battery & grid
interactive inverter stack
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Date: Friday, August 6, 2010, 6:17 PM

Yo, Mechanics~

A client is considering a "biggest ever for me" battery based power system.
They will probably scale down their ambitions once the cost realities settle
in but for now they've asked me to look for battery based inverter systems
which can scale bigger than a triple stack of Xantrex XW6048 inverters. Your
advice would be welcomed. 

* The system must be split phase 120/240, not 3 phase. 

* Outback seems "out" because the inverter group should handle backup
battery recharge using grid or generator AC...and we also want to sell
excess PV power to the grid.

* No cobbled together AC coupled systems would be considered without a
convincing way to feather the end of charge on the battery when the grid is
down...float & all. I don't want to go back to the days of clunky, coarse
battery "end of charge" care. 

* Sunny Island/Sunny Boy is in contention but I'm not keen on having to
stack in pairs to maintain the 120/240 three wire architecture. A single
Sunny Island failure would take down two of the yellow boxes. What is the
limit on stack-ability for Sunny Island?

* A battery sales rep suggested Satcon brand but I think that's bogus
advice. Satcon is pure grid intertie only, right?

***********************************************

So...there is your challenge de la semaine (challenge of the week). Who
builds an inverter system with Xantrex XW-like features only bigger...much
bigger? OR: who could supply the "Mother of Sunny Island/Sunny Boy" system?
Replies would be welcomed on the  List or off.

The Wrench List is the Bomb!

Mick Abraham, Proprietor
www.abrahamsolar.com

Voice: 970-731-4675

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