[RE-wrenches] Inverter with no overload protection?

Sat Sep 10 06:40:12 PDT 2011

Hello Allan, Dan, Ray and Wrenches ...

There's some misinformation posted below, which I'll address as soon as my time permits today.  I'm headed to a meeting where I'm due in 20 minutes.

Dan
Senior Engineer
Exeltech

--- On Fri, 9/9/11, R Ray Walters <ray at solarray.com> wrote:

From: R Ray Walters <ray at solarray.com>
Subject: Re: [RE-wrenches] Inverter with no overload protection?
To: Allan at positiveenergysolar.com, "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Date: Friday, September 9, 2011, 8:13 PM

I've long been an Exeltech fan, but they are the Pure bred race horses of inverters, beautiful wave form that exceeds Grid quality, but they are not a work horse.I put a DC breaker on them at 80% of name plate continuous rating. You read right folks, I want that breaker to trip, before something internal goes "poof".If people want starting surge, I sell them a 2nd inverter. The 80% breaker actually allows full load for maybe 10 secs, then trips, the customer calls, and I say "a coffee maker?! a Vacuum?! we didn't design for that....."I reserve Exeltech for things like tube amplifiers, HiFI stereo, Recording studios, sensitive metering equipment, or one client that had a $50,000 photo quality line printer that was very finicky about its power; stuff like that.No load to full load, Exeltech hold almost perfect waveform, but they are not as robust as the old mod sine transformer based inverters (whose waveforms can be ridiculous at load)
less than $50 sounds pretty cheap for the repair, I'd do that, and get the customer a bigger (cheaper) mod sine unit if her loads can handle it.Somebody (like me) will buy the XP125 off you for their portable sound project.

R. Waltersray at solarray.comSolar Engineer

Hi Allan;

That's amazing! I'll make a note of it for sure. I 
often work with tiny systems in remote areas that are transported by 
helicopter and boat, and even with many inexpensive inverters (for 
example Statpower) there's at least a line of automotive blade fuses 
inside that blow and can be easily replaced....one customer hit his 
output line with a snowplow, just had to buy 12 new fuses.

I 
highly recommend the Morningstar SureSine. It's bombproof, even for 
customers with no electrical knowledge. Just be sure to mount it in an 
electrical box, as there are no knockouts on the unit to clamp down the 
DC or AC wires.

Dan Fink
Executive Director;
Buckville Energy Consulting
Buckville Publications LLC
NABCEP / IREC / ISPQ accredited Continuing Education Providers
http://www.buckville.com/
info at buckville.com
970.672.4342 (voicemail)
970.373.1311 (fax)

On Sep 9, 2011, at 6:30 PM, Allan Sindelar wrote:

    Wrenches,

    A bit over a year ago I built a mini-system for a customer: One 135W
    module, SunSaver-10, 104 A/hr Concorde VRLA, Tri-Metric monitor and
    an Exeltech XP125 inverter. All but the module were installed in a
    plastic picnic cooler. The customer was totally satisfied with the
    system for this weekend getaway cabin system and used it well within
    its bounds - a couple of lights, mostly.

    Last week she called because the inverter had failed. I called
    Exeltech tech support and was told that the XP125 lacks protection
    against AC overload! There's no circuit breaker or internal shutoff
    protection, and an internal fuse on the circuit board is included
    only to protect against reverse polarity. And because the inverter
    has been in operation for 15 months, this apparent failure isn't
    covered under the one-year warranty. Send it in, under $50 to
    repair. 

    I wrote the customer about the load size and her (edited) answer is
    below. Apparently it wasn't even an overload, just a failure,
    possibly related to poor power factor in the cordless drill charger.
    But I still have never heard of an inverter without some form of
    overload protection, and it seems to me that a unit this small
    especially needs it, given how easily its capacity can be exceeded.

    I have long respected Exeltech, one of few domestic electronics
    products left. But this incident is giving me pause. Morningstar's
    SureSine claims extensive protection: "The SureSine has extensive
    electronic protections that will automatically protect against
    faults and user mistakes such as short circuit, overload, high
    temperature and low voltage disconnect. Recovery from most faults is
    automatic." It's looking better all the time.

    Has anyone else experienced a similar failure?

    Thank you,

    Allan

    -- 

    Allan Sindelar

    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

    -------- Original Message
    --------

          Subject: 
          (no subject)

          Date: 
          Fri, 9 Sep 2011 12:48:14 -0400 (EDT)

          From: 
          Joann

          To: 
          allan at positiveenergysolar.com

      Hi Allan, i just got your message.  I have a 7.2 volt
        craftsman cordless drill and I used the 1 hour charger.  As soon
        as I plugged it in, the inverter made a funny sound and
        everything went off.  the battery was operating 100%  - it was
        in the morning and nothing else was turned on. On the bottom of
        the charger it says:  dual charge rate 
                input: 120V AC  60 Hz 65 watts
                output:  7.2-24V DC  1.6A Battery Charger

      Yes, it's a little upsetting that this happened.  I remember
        asking you if I could overload it - one of my concerns and you
        advised me that wouldn't happen. I appreciate your taking care
        of this.  Thanks, Joann

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