Gday...

Really Alan, despite my understanding the reason for your post, does anyone really believe that the protagonists that prompted your angst are going to take any notice ... let alone change their ways. 

Unfortunately the equine seems to be beyond resurrection no matter how much flagellation is applied.

Cheers - John 

looks like the kangaroo court has labeled me a problem poster.

I'm not surprised that solar discussions degenerate into arguments. I'm just an observer when it comes to solar and battery technology, but ISTM that there is a huge diversity of opinion and very little consensus on subjects as mundane as the optimal method for charging a battery. There is also a dearth of performance reviews and inside photographs which would help a techie like me to understand the technology. To make matters worse, the terms used by the solar industry are ambiguous and at odds with what an engineer understands them to mean. "PWM" is one such example.

Ron-D wrote:

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We have both had our says Terry your wifes business is your business as well obviously,my business when I had it was my wifes as well,no backhand slap Terry just stating the obviouse,no one in there right mind would think my knowledge was better than anyone elses ,as far as solar thats what you do Terry or shall I say your wife does according to you,your knowledge there would be better then most here,just let others have a say regarding solar without coming over the top ,these things can be described without monstrous pages of text surely I think it puts others off contributing look at happened with your old Mate you wore him down ,Terry you have established you are in business or your wife is,on the forum anyone that wants your wifes work just simply has to p,m you,if you have a good enough following here theres work in it for your business obviousely...

-- Edited by Ron-D on Saturday 12th of January 2019 03:46:51 PM

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I won't deny I work here Ron, but someone who works for an business does not automatically become an owner in the business do they? The fact I'm an unpaid worker who only works when the body allows means my wife has to be the hands on owner operator in her own business. I can and do offer my knowledge to help solve a problem etc when required, but my wife has learnt an incredible amount of the subject over the yrs so my input is required less and less. If you have ever read her website you would see that, none of that is from my input, it is all my wife's because she is the one who would be dealing with the customer, not me, so she needs to be able to talk the talk as well as walk the walk. Margaret will be the one doing the 2 seminars at STC over Easter, I just can't do it any more because I loose track halfway through what I was saying  I'm much better at answering questions, I can keep my thoughts going in one direction then  Having my brains rattled in my skull 14yrs ago in a motor vehicle accident didn't do a lot of good as far as keeping track when trying to deliver a presentation I can assure you

T1 Terry  

T1 Terry wrote:

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what is the engineer's understanding of the term PWM or Pulse Width Modulation?

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I use the term "PWM" almost synonymously with "switchmode". Basically I distinguish between linear control and PWM control. Anything that modulates the width (aka duty cycle) of a pulse is PWM as I see it. That includes MPPT controllers. PWM also describes the operation of AC dimmers for incandescent lamps, and triac based speed controls for AC motors. Most power supplies in consumer appliances are switchmode, and these invariably use a PWM controller and chopper transistor, with the output being smoothed by an inductor and capacitor. However, the solar industry appears to limit the term "PWM" to describe a specific type of switchmode controller, with no smoothing components (other than the battery). Moreover, I don't recall ever seeing a battery charging circuit in modern appliances that delivered a pulsed current to a rechargeable battery, so that's something else to consider.

dorian wrote:

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T1 Terry wrote:

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what is the engineer's understanding of the term PWM or Pulse Width Modulation?

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I use the term "PWM" almost synonymously with "switchmode". Basically I distinguish between linear control and PWM control. Anything that modulates the width (aka duty cycle) of a pulse is PWM as I see it. That includes MPPT controllers. PWM also describes the operation of AC dimmers for incandescent lamps, and triac based speed controls for AC motors. Most power supplies in consumer appliances are switchmode, and these invariably use a PWM controller and chopper transistor, with the output being smoothed by an inductor and capacitor. However, the solar industry appears to limit the term "PWM" to describe a specific type of switchmode controller, with no smoothing components (other than the battery). Moreover, I don't recall ever seeing a battery charging circuit in modern appliances that delivered a pulsed current to a rechargeable battery, so that's something else to consider.

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Here is an example of a well known brand battery charger and how/when it automatically applies a pulse current to attempt to correct a sulphation problem

https://static1.squarespace.com/static/5939e22ac534a5226114de77/t/599149d3bebafb01ec325c9a/1502693886872/HDBM4000+Instruction+Manual.pdf 

and here is an instructables circuit designed to do a similar thing

https://www.instructables.com/id/Desulfator-for-12V-Car-Batteries-in-an-Altoids-Ti/  

The battery is just a big capacitor so no other smoothing circuit is really required on the output side, but I guess some sort of smoothing would be required for the MPPT part so the components were protected from feed back.

I remember seeing a video where some bloke was rubbishing the W7 type inverters claiming they were nothing more than square wave inverters under high load. What he had not considered was the fact he had a mains charger on the supply battery to provide enough current to power the inverter and what he was actually seeing was the square wave output from his crappy charger reflecting across and showing up on his CRO   :lol:

T1 Terry

Gday...

It didn't take long 

Cheers - John