[RE-wrenches] Propane Generator

[Allan Sindelar]

I have waited to hear what other Wrenches have recommended in order to learn
from you all. Here's my ridiculously long-winded $.02:

The generator article in the current HP took almost a year and several edits
to write. As long as it ended up being, it was substantially shortened from
early drafts. Every main point seemed to bring up more exceptions than
consistencies!

One of the key unexpected conclusions I reached is that there are actually
fewer and fewer good generators to recommend for off-grid use. The dominant
reason that I found is that the "home standby" market is much greater than
the off-grid market, and generator manufacturers are increasingly building
to this market. This means that generators are designed to be like a home
appliance, packaged and marketed for a mainstream homeowner who is likely to
install it and forget to do regular maintenance. They generally include
block heaters, grid interface (with phantom load), grid charger for the
starting battery, etc. The units will seldom see many hours of runtime, as
they're for "standby" use during an occasional power outage.

I too used to say "Kohler or Onan" when asked what's good (oh, and also
"stay far away from Generac"). We were even limited Kohler dealers from
around 1999, when the distributor recruited some PV dealers to carry Kohler
in anticipation of Y2K demand. But we stopped selling Kohler some years ago,
when the 10RY, 12RY, and 20RY 4-cylinder 1800 rpm units were discontinued,
and when the 8.5RMY and 11RMY units became the 8.5RES and 12RES. There was a
whole thread on this list about the RES series with its controller's phantom
load and need for an external battery charger. (Kirk Herander wrote this in
November 2004: "Have any of you used this generator in an off-grid
application? I have and there are a few curves to be aware of. The generator
has an electronic controller. It is quite slick and allows for some fancy
programming, but requires power (from the starting battery) when the
generator is off. Although the service manual states a 250 ma current draw,
the draw I measured is 685 ma. This will definitely draw the recommended
starting battery (675 CCA @ 0 degrees) down far enough to prevent generator
starting. The controller has an internal jumper, that if removed will power
down the controller after 48 hrs (in auto start mode (and who knows why this
time period was selected by the factory), but the battery will go dead
enough before the power-down. So my solution was to parallel 2 batteries
together to ride through this 48 hr time period. In addition, there is no
alternator/rectifier to charge the battery. Instead a 6 amp battery charger
is included which must be wired to an AC source (grid, inverter, or the
generator itself) to keep it charged. I measured the ac power draw of the
charger at 100 watts (i.e. 2400 w-hrs/day). Not too practical off an
inverter, unless it's put on a timer. The old 8.5 RMY did not have these
hassles.)

Even though the 8.5RMY and 11RMY were air-cooled 3600 rpm twins, they have
held up very well in off-grid use; way better than our expectations when
they came out. I am interested in how other Wrenches (especially Travis)
have worked out the issues noted above (and also the carburetor heater (!)
that Steve Willey noted way back then) with the RES series.

Likewise, Onan dropped its Commercial line and makes RV units and home
standby units in LPG versions. The RS12000 comes recommended, as it has no
standby load. It uses a Subaru 3600 rpm twin and has a weather shroud. I
recently recommended it to an off-grid client, and they asked me to source
it. The sales rep at our Cummins-Onan distributorship told me that this was
a good unit, but it is being discontinued, as it's too expensive to compete
in the home standby market with Kohler and Generac! It will be replaced by a
cheaper model. That's the second big development away from generators for
our off-grid needs: the home standby market appears to be a race to the
bottom, with price point marketing being the prime determinant, rather than
quality. Beware!

Kohler's 10ERG works well for off-grid, according to Backwoods (I haven't
seen or tried one), but it's not available with a weather shroud. I'm
curious about others' experience with the 1800 rpm 15kW Kohler, and whether
it's a good choice (the same engine runs at 3600 rpm with a different
generator can for Kohler's 30kW unit!). Onan's RS12000 has a two-year
warranty in residential standby application, but only one year when used off
grid - what does that tell you about where the market is going? 

I appreciate Travis' advice against the initial cost and service cost of
1800 rpm commercial units. And Michael Welch has noted he likes the option
of spending that $4-10K on oversizing the PV array and batteries. I'm
beginning to think he's right on, maybe along with a small inverter-based
portable unit like Todd occasionally uses.

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: On Behalf Of Richard L Ratico

Ian, 
I like Kohler too, but, last time I checked, you needed  at least 
the 15KW model to get an enclosure, 1800 rpms and an onboard alternator. 
The Backwoods Solar Catalog recommends the Kohler 10ERG. 
It may not be available with an enclosure. According to them, it's 
classified as mobile, so, no UL listing though you can get a warrantee.

Whatever, be sure the dealer knows it's offgrid if you want the warrantee.
Otherwise, if there's a problem, they may claim, "But it's only for grid
backup use". It's happened to one of my clients. We have a weasel here who
moved from selling weedwackers to being a dealer for Kohler. He knew it was
offgrid. Doesn't say much for Kohler distribution.

All stationary generators are STATIONARY. If you need service, they come to
you. Make sure you've got a good dealer/service setup.

I've heard good things about Lister-Petter Hawkpower Propane Generators, but
was advised to avoid the smallest units because of vibration issues. I've no
experience with them. No experience with Onan either.

Honda, Robin-Subaru and Yamaha now make inverter type generators up to 6500
watts, still probably too small for two Outbacks. They are three wire start.

I believe all of them have to be converted to propane by third parties
(warrantee implications?). We're fortunate to have a local guy who's good at
that. I've had good luck with Honda and Yamaha.
I drive a Sube:-)

Dick
Solarwind Electric
Bradford, VT 

--- You wrote:
A client with a remote off-grid system and two OutBack FXs is looking 
for the right generator to buy. He prefers propane because they already have
it on site. Any recommendations?
Thanks, Ian