Instant benefit from replacing Solar PWM with MPPT controller?

[Reefmagnet]

Originally Posted by StuM

Actually, I'm not even seeing misinterpretations, just a bunch of "you're wrong", "you don't understand" and "you are a ...." without any of the detractors pointing out a single error in my posts.

To layman, who tend to ask the questions you answer using your kVA vs W answers as an example; Do you really think they would be expected to understand the terms "scalar", "vector", "rms", "reactance" et al? How can you explain something with clarity using descriptions your audience may not understand?


And I never said you were wrong in your answer. I said you were confused because you demonstrated knowledge of the theory, but stumbled in describing it from a practical perspective.

[StuM]

Originally Posted by sailorchic34

Hum. So a current load of 5 amps for 90 seconds is how many Ah??? The answer is not 5.

Yes amps is the flow of current per unit time, but that unit of time is seconds, not hours. A current of 5 ampere (or amps) is five coulomb of charge (A really big number of electrons in Boat DC land), going past a given point per second. If that load continues for one hour, then you have used 5 Ah.

Oh, dear Lord - give me strength!

Anyone with a basic understanding would not need to ask that question. It is blatantly obvious that the answer is not 5, because 90 seconds in not one hour.

Your whole post demonstrates a total lack of understanding still.

Amperes are not "the flow of current per unit time". Ampere is a measure of the INSTANTANEOUS RATE of flow of electric charge .

(Dare I mention gallons per hour again? )

Under the older CGS system, the SIZE of ONE AMPERE was indeed defined as "one coulomb of charge per second".

Under the SI system that is no longer so. The Ampere is now defined in terms of force per metre length in parallel conductors. The SIZE of ONE COULOMB is then defined as the charge carried by one Ampere in one second.

When you talk about energy in terms of current per unit time, that unit time can be anything you want. It is not limited to the second used in defining the size of one coulomb.

The most practical "unit of time" for people here is the hour or the day.
Hence the frequent use of "Amp Hours" and "Amp hours per day".

[Reefmagnet]

I blame our reluctance to recognise the

Coulomb

leading to this shamozzle.

Edit: Dam you Stu you beat me to it!

[Kelkara]

Originally Posted by sailorchic34

Silly me I equate current=charge.

There are many aspects of boating and sailing where I would happily take advice from someone who equates electric charge and current ... but battery charging ain't one of them ... sorry.

[StuM]

Originally Posted by FionaJC

So for all intents and purposes you agree that a 2kW generator will deliver about 8.69 Amps and will do it for hours on end in the UK (Fuel and MTBF allowing) but 18.18 amps in the US. And if they both run for two hours they will have delivered 17.38A and 36.36A respectively. Which is 8.69A in an Hour or 18.18 Amps in an hour. Friends drink 2 beers each BUT WHAT ABOUT PWM vs MPPT which the op or OP asked??

You claim to be an Electronic Engineer with a degree in that discipline and yet you make a fundamentally wrong statement like that?

You and SC make a great pair - you should get together.

[StuM]

Originally Posted by FionaJC

As we are discussing minutiae Heating loads have an element of inductive load

Agree than nothing in the world is perfect, but the inductive component of a normal heater's load is neglible.

[Mr B]

As a Layman, The answer to the OP's question, Is yes, MMPT is better than PWM,
The rest is well and truly over the Laymans head,

I enjoy my beer out of Stubbies, Hahahahaha

[sailorchic34]

Originally Posted by StuM

Under the older CGS system, the SIZE of ONE AMPERE was indeed defined as "one coulomb of charge per second".

Under the SI system that is no longer so. The Ampere is now defined in terms of force per metre length in parallel conductors. The SIZE of ONE COULOMB is then defined as the charge carried by one Ampere in one second.

How Odd it is that I learned Ampere's under the CGS system. But then I still use feet, inches and other antiquated measurements.

I do so love the SI definition of an ampere describing two straight parallel conductors of infinite length. I tried to find two conductors of infinite length at the hardware store and they were all out.

I'll Stick with the CGS definition of Ampere, thank you very much. It does still work after all, as does feet and inches.

[sailorchic34]

Originally Posted by StuM

You claim to be an Electronic Engineer with a degree in that discipline and yet you make a fundamentally wrong statement like that?

You and SC make a great pair - you should get together.

LOL, I told dear FionaJC you would be by to slap her hand. Frankly I would rather raise a pint with FionaJC. A far more interesting person.

[Paul Elliott]

Originally Posted by sailorchic34

Hum. So a current load of 5 amps for 90 seconds is how many Ah??? The answer is not 5.

Yes amps is the flow of current per unit time, but that unit of time is seconds, not hours. A current of 5 ampere (or amps) is five coulomb of charge (A really big number of electrons in Boat DC land), going past a given point per second. If that load continues for one hour, then you have used 5 Ah.

I'm not sure what point you're making here. What makes you think that I believe 5 A for 90 seconds equals 5 Ah? 5 Amps for 90 seconds is 0.125 Ah. Or 450 Amp seconds. Or 450 Coulombs. Is there a problem with my analogy, or use of the terminology?

And Amps is not specifically the flow of current over a second. Yes, you can use one second in the definition, just as you can describe speed as "miles per hour" or "meters per second", but you don't have to drive for one hour or one second to go a particular speed -- the "hour" is just a convenient way to measure it. "Amps" is a measure of the instantaneous rate of electron flow.

"Amps per hour" is not the same as Ah. To use it as such is incorrect and leads to confusion.

[TheThunderbird]

Originally Posted by StuM

Is that anything like gallons per hour?

That should be kVA .

k = standard metric prefix for 1000.

V and A are capitalised because those units are derived from persons names.

for everyone's benefit, let me politely contradict you :-)


in metrics, for both physicists and engineers, CAPITAL letters are used for absolute values, dimensions which are invariant throughout the universe.

1 V is alike all around the universe, an absolute measure, nothing to do with Messrs.Ohm, Ampere, Volta....

Temperature is "T" or "K"
Time is "t"

Dimensional analysis is the first check any engineers do in calculations and equations.

[FionaJC]

Originally Posted by sailorchic34

LOL, I told dear FionaJC you would be by to slap her hand. Frankly I would rather raise a pint with FionaJC. A far more interesting person.

I remember being told, although I might not quote it as given exactly, "if you can't successfully explain it to a 10 year old then you don't really understand it". I'm sure that StuM can correctly tell us all exactly what I was told with the date and time but it won't change the basic gist. Proof of the pudding- MPPT works better for me than PAM does.

[StuM]

Originally Posted by TheThunderbird

for everyone's benefit, let me politely contradict you :-)

in metrics, for both physicists and engineers, CAPITAL letters are used for absolute values, dimensions which are invariant throughout the universe.

1 V is alike all around the universe, an absolute measure, nothing to do with Messrs.Ohm, Ampere, Volta....

Temperature is "T" or "K"
Time is "t"

Allow me and The International Bureau of Weights & Measures who administer The International System of Units (SI) to correct your contradiction.

This time I will, regardless of Reefmagnet's disapproval, make a direct copy and paste from the ultimate authority:

https://www.bipm.org/en/publications...ection5-1.html

Unit symbols are printed in roman (upright) type regardless of the type used in the surrounding text. They are printed in lower-case letters unless they are derived from a proper name, in which case the first letter is a capital letter.
An exception, adopted by the 16th CGPM (1979, Resolution 6), is that either capital L or lower-case l is allowed for the litre, in order to avoid possible confusion between the numeral 1 (one) and the lower-case letter l (el).

Dimensional analysis is the first check any engineers do in calculations and equations.

That is clearly untrue for the two people who have claimed to be engineers in this thread. In fact the whole concept of dimensional analysis appears to be totally unknown to them ( even though we spent a lot of time trying to explain it to one of them in a thread referenced earlier)

[FionaJC]

Originally Posted by sailorchic34

How Odd it is that I learned Ampere's under the CGS system. But then I still use feet, inchesof Ampere

I started with FPS then SI. I use everything cm / mm or inches/feet whatever is convenient at the time. Most device's from rulers to speedometers have both in UK. But what really annoys our children is that i use C when its <10°C and Fahrenheit >50°F. It's referred to as centiheit or fahrengrade in our house.

[FionaJC]

Originally Posted by StuM

Allow me and The International Bureau of Weights & Measures

Bestest buddies? Including yourself in their is incredibly arrogant. By all means quote an authority but don't go d yourself to them unless you are a member. I'm sure SC will agree, I think we are becoming an authority on StuM posts and will quote him often in the pubs and clubs.