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Tim_the_bloke Senior Member Joined: 15/11/2009 Location: AustraliaPosts: 105
Posted: 09:45pm 24 Oct 2016
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I have a disappointing inverter and would love to read the thoughts of wiser and more experienced tinkerers. GSL Traveller Series 1500W power inverter. Model INV1500-12 Made in Australia. Approx 16 years old. Had very little use.
It is connected up to deep cycle 12V lead acid batteries charged by solar and wind, with plenty of stored power. The problem is that the inverter outputs less than 240V AC, more like 215V. This is OK to run a power drill, bench grinder, etc but not all appliances. The toaster will slowly dry out a slice of bread but not brown it. It killed the charger for my Bosch cordless drill. It blew the fuse on my 240V soldering station.
I wonder if it was designed to run in a vehicle at 13.5V and is producing lower voltage as the input is 12 point something volts DC instead of 13+V DC. Next trip up to the hobby farm I intend to pull the inverter apart and see if there might be some trimpot adjustment. Any thoughts?
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 10:27pm 24 Oct 2016
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You could try contacting the manufacturer on 02 9620 9988 or info@gsl.com.au
http://www.gsl.com.au/There are only 10 types of people in the world: those who understand binary, and those who don't.
Tim_the_bloke Senior Member Joined: 15/11/2009 Location: AustraliaPosts: 105
Posted: 12:09am 25 Oct 2016
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Yes, I know they are still in business but I was hoping someone had experience with these inverters.
yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166
Posted: 01:20pm 25 Oct 2016
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No, it should work up to 15 volts and down to the 10.5 volt cutoff. I'm confused, no wait... maybe I'm not...
VK2MCT Senior Member Joined: 30/03/2012 Location: AustraliaPosts: 120
Posted: 09:03pm 25 Oct 2016
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I wonder if the output is a sinewave or some variation of a square wave ? John. VK2MCT
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 09:47pm 25 Oct 2016
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I googled the model, user manuals and specs are online, it is square wave.There are only 10 types of people in the world: those who understand binary, and those who don't.
oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 05:36am 26 Oct 2016
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No-one else seems to have any experience with these things. and nor do I.
But.... they are all basically the same... being 16 years old it probably uses a tl494 or KA7800 etc for the voltage controlled pwm source for the multiple push pull stages that give you the transition from 12v to 340 volts or more.
This is stored in the HV dc caps, then another chip creates the drive for the H bridge to give you the modified sine wave.
All simple if you say it quickly.
So first up measure the HVdc at the storage caps, and if below at least 340vdc, then we are looking at the feedback circuit to the 494... probably an opto isolator... and tweak that back upto the 340 or more.... that should be where the problem is.
After that, your on your own, as I don't know if they bother to modulate the wave form for the 240v output... I think they just blindly convert DC to AC, and rely on the feedback in the tl494 stage to keep the DC voltage stable according to the load.
Being modified sine, they rely on the area under the line of the graph of the wave to be equivalent to the DC rms power of 240v dc.... but it also has to have the 340v peak to satisfy a lot of other devices that rely on the peak of the 240v rms ac wave for their operation to work .. (thats the 1.414 x 240v=340v).
Without this peak voltage, your pwm power supplies will possibly fail ( depending on head room), as their pwm driver will be over doing the pwm width trying to get a proper output with a low supply voltage from lack of peak when they rectify the incoming mains from your inverter.
So the modified sine is really few square wave forms that will emulate a 240v rms power average.... with a 340v peak.
When working properly, it will power most loads ok... although not so much with inductive loads that would be happier with a smooth sine wave ( induction motor).
Hope that helps with your problem somehow.
.......oztulesEdited by oztules 2016-10-27Village idiot...or... just another hack out of his depth
Tim_the_bloke Senior Member Joined: 15/11/2009 Location: AustraliaPosts: 105
Posted: 03:32pm 26 Oct 2016
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Mmm... Tracing through the circuit board is probably beyond me but I will have a look inside it. I am still hoping to find obvious trimpots or similar.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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