[RE-wrenches] Inverter with no overload protection?

[R Ray Walters]

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. Walters
ray at solarray.com
Solar Engineer




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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