[RE-wrenches] Question on Back up generators
Dana
dana at solarwork.com
Thu Apr 9 14:32:42 PDT 2015
KOHLERS RSA14 - 14 KW is the same I have to run and AC circuit to the gen to
run a battery charger from the inverter. A 30 Watt PV module in the winter
is not enough if it is cloudy for a week. The battery dies and has frozen.
Again the control board is too much draw and does way too much.
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Dana Orzel
Great Solar Works, Inc - NABCEP # 051112-136
E - dana at solarwork.com - Web - solarwork.com
O - 970.626.5253 C - 208.721.7003
"Responsible Technologies for Responsible People since 1988"
P Please consider the environment before printing this email.
From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On
Behalf Of Ray Walters
Sent: Thursday, April 09, 2015 3:18 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Question on Back up generators
I used an Ecogen recently, and I liked many aspects of it. However the
continuous draw of the on board electronics is just ridiculous for an off
grid generator.
A 15 w solar module charging the start battery was barely able to keep up
with the draw. Running AC off the inverter to the generator is also just
another unnecessary 24/7 phantom load.
We may be 20 years into the future, but no one has built a generator that
can hold a candle to the old water cooled, 1800 RPM Kohlers. Most of those
are still in service, and had simple 2 wire start. The Ecogen's onboard
computer is a serious design flaw IMO. We don't need the generator to
"think" in an off grid system; we already have inverters that do a much
better job of that. The generator just needs to start reliably when its
called upon.
I would appreciate if someone with more experience with the Ecogens could
explain why the on board electronics are good, or...... how to bypass them
completely.
We had a great off grid generator solution 2 decades ago, and the closer
today's manufacturers can get back to that, the better we and our customers
will all be.
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 4/9/2015 2:40 PM, Gary Willett wrote:
Dana:
Take a look at the new Generac EcoGen 15kW that was purpose built for a
renewable energy system*
* including an inverter, battery bank and alternative energy power source
http://gens.lccdn.com/generaccorporate/media/library/content/all-products/ge
nerators/home-generators/ecogen-series/15kw-6103/0k8466-c-15kw-ecogen-hsb.pd
f
The 15kW EcoGen has the same footprint as the 6kW EcoGen (LP only) and is
natural gas or LP gas capable. The generator has a constant frequency /
variable speed AVR based on electrical demand.
Also, 500 run hours between oil changes. And a 3-year or 2000 hour warranty.
http://gens.lccdn.com/generaccorporate/media/library/content/all-products/ge
nerators/home-generators/ecogen-series/ecogen-warranty-0j1629-revb.pdf
Regards,
Gary Willett
Icarus Engineering & Solar Services LLC
On 4/9/15 9:56 AM, Dana wrote:
I agree but full load charging usually only lasts but a few minutes as the
inverter charge rate drops readily as voltage rises. 8300 watt -10,000 watts
or 13000 watts the point is why we are installing air cooled throw away
generators that run so fast & hot that they need to be replaced in 2,000
hours, not to mention the fuel consumed at 80 MPH?
Is there a slow speed (1200-1800 rpm) water cooled 8-13 KW generator out
there?
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Dana Orzel
Great Solar Works, Inc - NABCEP # 051112-136
E - dana at solarwork.com - Web - solarwork.com
O - 970.626.5253 C - 208.721.7003
"Responsible Technologies for Responsible People since 1988"
P Please consider the environment before printing this email.
From: Jerry Shafer [mailto:jerrysgarage01 at gmail.com]
Sent: Wednesday, April 08, 2015 7:02 PM
To: dana at solarwork.com; RE-wrenches
Subject: Re: [RE-wrenches] Question on Back up generators
We don't install anything smaller then a 13 k its air cooled but works well,
as far as the numbers you have, Mine are somewhat different I use max
potential load and max potential charge as when the batteries are low the
genny must not only supply the home but also charge the bank back up at a
reasonable rate, so if the loads are high and the genny only has enough to
maintain that load then what about the batteries plus I only use 75% of the
genny rating for optimum or improved duty cycle. This is only me and I am
sure every shop has there own math.
Jerry
On Wed, Apr 8, 2015 at 11:23 AM, Dana <dana at solarwork.com> wrote:
Hey All -
I just got off of a phone call with my Onan generator supplier. Last
conversation with Kohler was the same story basically.
I was informed that their smallest water cooled generator, the RS22 (22 KW)
is now no longer "rated "for off grid. They actually called me to confirm
that this generator was for backup power to a utility inter connected house.
Tier 4 generators in the EPA CFR 40 is the Federal code what covers this, &
you are allowed 100 hours of run time for standby power and maintenance per
year.
Q - Why am I using ridiculous sized generators for something that an 82-8300
watt generator does just fine?
A - The EPA current requirements, a shrinking economy, & manufacturers that
have to meet very expensive air quality compliance.
The Penalty - If you get caught running a "standby power only" generator the
fine is now $39,000 per day!
Now I am far from a polluting kind of individual and all for air quality but
this is getting the best of us. The 13KW air cooled generators are only good
for 2000 hours, & the water cooled go 20 years of moderate usage but cost a
boat load. I hate having the "Generator" talk with a new client they look at
me like I am crazy. So the air cooled units are basically throwaways and the
22KW units are way more than we need and what a client needs to spend money
on, unless you are at 10,000 ft el.
If you figure 30 amps/120 VAC input per inverter +/- x 2 = 7.2KW plus say
10-15% fudge or elevation factors would require an 8200-8300 watt generator.
Air cooled at 3600 RPM = 80 MPH & 1800 RPM = 40 MPH. Even if the generator
were a bit smaller, ran slow (1200-1800 rpm) and ran a bit longer that would
be acceptable.
So, why are we installing even 13KW air cooled or 22 KW water generators?
There is a business opportunity here folks.
What are you all installing?
Why?
Is it reliable?
Would you use it on your house?
Thanks for sharing all the wisdom and knowledge.
----------------------------------------------------------------------------
Dana Orzel
Great Solar Works, Inc - NABCEP # 051112-136
E - dana at solarwork.com - Web - solarwork.com
O - 970.626.5253 C - 208.721.7003 - No FAX Line
"Responsible Technologies for Responsible People since 1988"
P Please consider the environment before printing this email.
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