[RE-wrenches] Kohler 8.5 RES

[Allan Sindelar]

Drake,

I have just been told by the Kohler rep that the RES is now 120/240 only and
cannot be rewired to 120VAC.

 

I just ordered one for off-grid and went over all of this. There’s no block
heater, but there’s an AC carb heater. I will wire this through a 1-hour
mechanical time switch. 

 

Here’s what I wrote in my proposal to the customer (Magnum MS4024AE,
120/240V, 7,000 foot elevation and cold winters):

            I recommend a Kohler 8.5 RES generator for your application (for
specifications, see http://www.kohlerpower.com/onlinecatalog/pdf/g4097.pdf;
for dimensions see
http://www.kohlerpower.com/onlinecatalog/pdf/adv6823.pdf). In my estimation,
this unit offers the closest combination of attributes to meet our objective
with adequate after-sale support available. This unit is designed for
residential standby power (“RES”) for on-grid application, and thus has
power draw in standby mode that is typically supplied by the utility grid. 

 

                        The unit uses an electronic generator controller
with modest (estimated at 200-700 mA, depending on state of operation) draw
on the starting battery. This controller drops to minimal “sleep” draw
automatically after 48 hours of non-operation. This generator does not have
a starting battery charging coil, but rather uses a separate AC battery
trickle charger to maintain the battery. I will install a 20W PV module and
small charge controller on the generator to keep the starting battery
charged. I will also install the AC charger to operate whenever the
generator is running. While this combined setup has worked successfully for
other installers with whom I have spoken, if this proves insufficient I can
later add a switch and relay to allow the charger to also operate off of
inverter AC if ever needed.

 

            The unit also requires a built-in carburetor heater to operate
during cold weather. This heater is normally controlled by a thermostat to
conservatively come on at or below 40°F, which would mean that it would
operate nearly continuously during Taos’ winter months, draining the PV
system. My solution is to put the carburetor heater on a manual mechanical
one-hour time switch located at the generator; you will activate the heater
through this switch 15-30 minutes before starting the generator. 

 

Hope this helps.

Allan

 

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

  _____  

Hello Wrenches
A client is interested in a Kohler 8.5 RES.  Looking at the archives, it
seems likely that these can be rewired for full output at 120 V, and it
should be possible to separate the neutral from the frame ground.  Does this
seem correct for this particular unit?
The system is fully off grid.  It is unclear to me if anyone has found a way
to stop the power drain of the system electronics without draining the
starter battery?
Thanks,
Drake Chamberlin
Athens Electric



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