[RE-wrenches] Cummins DC generator

Mon Oct 24 23:18:36 PDT 2011

I have always liked the idea of running a dc charger into a battery bank.

In the past I have played with the "incharge" from Xantrex, it was an
incredibly difficult unit to program. It had magnet switches located in the
potting epoxy that you had to activate to adjust the settings and it went in
a specific order. Miss one and you were back to the start and do it again. I
grew to hate it and relatively quickly.

It had lots of adjustability but I could not master the adjustment process.
I ultimately changed battery voltage and it was no longer useful to me. 

I think the original idea was built by Bob O and I have people who have used
them and it worked well. It had 2 knobs to do the adjustments, I understood
that!

I just could never build one, boards aren't my thing. I had a friend build
one for me and that was a massive failure.

I still would like to find one of Bob O's units to use.

As usual just my .02 worth.

Bob Ellison

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of R Ray
Walters
Sent: Monday, October 24, 2011 10:55 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Cummins DC generator

They show them as being used specifically for off grid solar applications
including remote homes, but I'm with you, I don't understand the voltage
limitation.

They seem to think they are just replacing the battery while running, not
actually charging it. Very weird. I even went through their case studies,
and I'm wondering if they might end up with some long term sulfation
problems. It seems they're only interested in reducing the battery size, not
augmenting the PV charging; seems a waste of fuel.

I linked to these for Allan earlier just as "food for thought" I wasn't
actually advocating their use. It does look like a decent generator, so
possibly the voltage limitation could be overcome?

I remember another DC gen set, that ran a Honda motor to belt belt drive a
truck alternator (late 90s). I recall them being something of a pain.

Here's another that looks interesting, and actually can be adjusted up to 64
vdc: http://polarpowerinc.com/products/generators/index.htm

Once again, I'm just sharing the info, not advocating these.

R. Walters

ray at solarray.com

Solar Engineer

On Oct 24, 2011, at 6:30 PM, bob ellison wrote:

I downloaded the spec sheets on the DC generator, it's either LP or natural
gas. Also it's regulated to 26 volts or 52 volts, so it's about useless to
charge batteries in an off grid system, unless you just need to feed power
to the battery bank.

Bob Ellison

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Ray Walters
Sent: Friday, October 21, 2011 7:41 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Three-phase off-grid

HI Allan;

I haven't tried the large Exeltech inverters, but I could see some
advantages to having a separate charging system, and keeping the inverters
supplying stable power. Everytime a generator coughs or switches from one
source to another, it seems to cause trouble. The generator could be sized
smaller, since it wouldn't need any surge capability. It would always run
the same charger, and the inverters would always run the same loads. I'd at
least take another look at it for my next large project, but cost might be a
limiting factor.
Here's a Cummins diesel DC generator, just to think about:
http://www.cumminspowerproducts.com/DCgensets/Other/10000500.pdf

Ray

On 10/21/2011 4:56 PM, Gary Willett wrote:

Alan: Thanks for setting me straight about 3-phasing the Outback Radian - I
was not aware they are limited to parallel single phase applications.

Regards,

Gary Willett

On 10/21/2011 15:29, Allan Sindelar wrote:

Gary,
I was surprised by this information, as I had presumed that both units were
for single-phase only. So I checked.

Mary Raub in tech support at Outback told me that the Radian works only in
120/240 single-phase, although they are stackable in parallel.

Someone in Schneider tech support told me that the XW can be used in
three-phase, up to six units (36 kW). Setup instructions are in Appendix D
of the XW installation guide, found online at
http://www.global-download.schneider-electric.com/85257849002EB8CB/all/5CC68
9CC3CB7FD10852578BF005EA759/$File/xw-hybrid-inverter-charger_installation-gu
ide%28975-0239-01-01_rev-e%29.pdf.

Thanks, Allan

Allan Sindelar
 <mailto:Allan at positiveenergysolar.com> Allan at positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com <http://www.positiveenergysolar.com/> 

On 10/21/2011 2:01 PM, Gary Willett wrote:

Allan:
Also, you might consider using six to nine Schneider/Xantrex XW6048
inverters, or  six to nine Outback Radian GS8048 inverters, in a 3-phase
configuration, with a common battery bank.
Also, Schneider/Xantrex has an 80A 600V charge controller that may be
advantageous depending on the distance from the PV arrays to the inverters.

Regards,
Gary Willett, PE
Icarus-Engineering LLC

Icarus Solar Services LLC

On 10/21/2011 10:17, Allan Sindelar wrote:

Wrenches,
We have been asked for a design for an off-grid system to reduce generator
runtime for a mountain resort. Initial projections (consumption measurement
results not yet available) suggest 15-20 kW of PV and around 30 kW of
inverter capacity. However, the generators and existing wiring are
three-phase 120/208.

My assumption is that our only options are a set of six Sunny Islands, or
9-12 Outback GVFX3648s. Are there any other options or approaches that I'm
missing?

Thank you, Allan

-- 
Allan Sindelar
 <mailto:Allan at positiveenergysolar.com> Allan at positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com <http://www.positiveenergysolar.com/> 

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