[RE-wrenches] Question on Back up generators

Thu Apr 9 20:35:45 PDT 2015

I'll echo the avoid Generac, at least under 50 kW or so. When people are price shopping between cheapo generators I sarcastically suggest they get 3 of the cheap ones, then there is a good chance one will actually work when needed. 

The 10 year ago model of the Onan / Cummins RS12,000 was a great LPG generator. Then they went and put a fancy computer board in them with the associated parasitic power draw issue so made it no longer suited to off-grid. 

We have been using the Cummins Onan Commercial Mobile series for many remote off-grid sites recreational or commercial ie repeaters. 2880 RPM. Available in 2.5, 3.6, 5.5 and 6.5 kW sizes, LPG or gasoline. Three wire remote start units that just work. Just a bit small for larger sites, where we typically move into a diesel. We have several dozen of them out there and they work reliably. The models have been the same for many years, these are used by OEM's for integration into all manner of RVs, ambulances, etc. Have many units over 7,000 hrs of operation. They start pretty reliably down to -30oC. 

For customers who are in it for the long haul with larger power demands I generally move them to a small 1800 RPM diesel, Kubota, Isuzu, Yanmar brands. Install it properly maintain it properly and will get at least 30,000 hrs from it. Twice the cost to buy but half the cost to run. Wins in the long haul. 

Kevin

-----Original Message-----
From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org]On Behalf Of Dana
Sent: April 9, 2015 2:18 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Question on Back up generators

I am going out on a limb here - In 26 years of installing generators I have only seen (2) Generacs that were actually working, one was a 30 KW and the other smaller. I have removed/replaced in excess of (25) Generacs that have died for a variety of issues: fire, controller blew up, engine seized (several times) over that time span.

Primarily because the owners were totally fed up with getting them fixed and having to rent a temp replacement while the wreck was in the shop. For some of these people they had to drive 2+ hours each way to get it to an approved service center. Enough said I will stop there.

I am aware of the ECOGen and again it is 2,700 to 3,600 RPM. 3,600 RPM is 80 miles per hour with an air cooled engine.  How do you expect long and reliable life there?

Interesting on the 2000 hour warranty that seems to be the hour limit on most air cooled 3,600 rpm unit where they fail, & Oil changes at 40,000 miles exceeds AMSOILs synthetic 25,000 mile best oil rating by 15,000 miles. However the prior 26 years of experience have taught me to be very careful here.

I am curious as to actual life on these units and other folk's experience. Chime in here...

Still looking & voting for a water cooled slow rpm 10 KW.............

----------------------------------------------------------------------------

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 Gary Willett
Sent: Thursday, April 09, 2015 2:41 PM
To: re-wrenches at lists.re-wrenches.org
Subject: Re: [RE-wrenches] Question on Back up generators

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/generators/home-generators/ecogen-series/15kw-6103/0k8466-c-15kw-ecogen-hsb.pdf

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/generators/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?

----------------------------------------------------------------------------

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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