Instant benefit from replacing Solar PWM with MPPT controller?

[FionaJC]

Originally Posted by StuM

Ashley, the dash in watt-hour doesn't mean anything and it is not a recognised unit name.

The correct forms are "Watt hour" and "Wh". Note the upper case "W" and lower case "h".

For those who are still unsure about the appropriate units, you may like to peruse:
http://www.cruisersforum.com/forums/...ml#post1933764

Read the whole thread if you want to waste a couple of hours seeing how difficult it has been (and apparently still is) for some here to grasp the simple basics.

Chink in the armour dear StuM - Watt about Kva?

[StuM]

Originally Posted by sailorchic34

Per CAN mean divided by, but it may also be used to mean "for each" as well.

Earwig ho! Yet again

No "but" or "also" about it.

There is no difference between "divided by " and "for each" ?

I have one cake and four people - each gets a quarter of the cake.

1/4 = " One cake divided by four", "one cake divided between four people", "one cake divided into four pieces", "one cake for each four people" and "one cake per four people."

It doesn't matter how you express it, the concept is exactly the same.

[StuM]

Originally Posted by FionaJC

But they simplify for non-engineers who would otherwise be confused.

Using incorrect units is not simplification. It adds to the confusion.

[StuM]

Originally Posted by FionaJC

Chink in the armour dear StuM - Watt about Kva?

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.

[FionaJC]

Originally Posted by StuM

Using incorrect units is not simplification. It adds to the confusion.

4,000,000 Nautical miles, 4,000,000 Swedsh miles 4,000,000 Statute miles or even 1 light year is a bloody long way - simplification.

[mvmojo]

We got about a 20% increase in amp/hours out of our solar panels when we changed from PWM to MPPT (Midnight Solar Outback controller).

[FionaJC]

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.

I had a teacher just like you, I proved him wrong more than once and he lost all credibility. I have an Electronics engineering degree, a PhD in computer science, run two companies and he is still a teacher. He also told me that women shouldn't do science, we don't have the brains for it.
You remind me of him a lot. Youre real name isn't Richard Edwards is it?

[FionaJC]

Originally Posted by FionaJC

Youre real name isn't Richard Edwards is it?

English Joke, for simplification we use nicknames
Richard becomes "Dick", Edward becomes "Ed", I know that's a simplification StuM but I'm sure that you can work it out or would you like me to explain it?

[Reefmagnet]

Watts the difference between VA and W???

[Kelkara]

Originally Posted by FionaJC

4,000,000 Nautical miles, 4,000,000 Swedsh miles 4,000,000 Statute miles or even 1 light year is a bloody long way - simplification.

But you have simplified a distance with another distance.
4 miles, 4km, 4 nautical miles, 4 knot hours, all distances. But 4 knots per hour is an acceleration and something completely different.

As someone who doesn't really know the difference between a PWM and MPPT controller I'm interested to learn, and so this thread is interesting ... Although I understood the initial use of "watts per hour" as it was intended ... I've never before met an engineer whose language doesn't instinctively differentiate between multiplication and division.

To be told that it was done to make it simpler to understand is like asking a question about the french language and getting the answer in franglais because maybe I don't speakie frenchie very well ... it's either patronising, or it casts doubt on the authority of the source.

[svlamorocha]

Originally Posted by sailorchic34

Per CAN mean divided by, but it may also be used to mean "for each" as well.

Both meanings are the same.. Or do we need a separate thread about math?

[svlamorocha]

Originally Posted by StuM

Earwig ho! Yet again

No "but" or "also" about it.

There is no difference between "divided by " and "for each" ?

I have one cake and four people - each gets a quarter of the cake.

1/4 = " One cake divided by four", "one cake divided between four people", "one cake divided into four pieces", "one cake for each four people" and "one cake per four people."

It doesn't matter how you express it, the concept is exactly the same.

I am with Stu on this!

[svlamorocha]

Originally Posted by StuM

Ashley, the dash in watt-hour doesn't mean anything and it is not a recognised unit name.

The correct forms are "Watt hour" and "Wh". Note the upper case "W" and lower case "h".

The American Physical Society seems disagree with you when they say that "The kilowatt-hour is a standard unit of electricity production and consumption." See https://www.aps.org/policy/reports/p...ergy/units.cfm

The way to make sense 1 kilowatt-hour = 1 kW x 1h is to take the dash as a multiplication sign.

Let´s not drown in a glass of water; the kWh and Wh are common metric units but they are not SI units, hence there is no governance system to say what is the right "spelling".

[StuM]

Originally Posted by Reefmagnet

Watts the difference between VA and W???

The difference is only significant if talking about alternating current.

Watts is "real power" , VA is "apparent power".

The real "difference" is the "reactive power" in the circuit.

But it's probably simpler to consider "power factor" for equipment using alternating current. The power factor is the ratio between the two.

Power factor = W/VA

Real power (W) is the power that performs work or generated heat. It is the integral of instantaneous voltage multipled by instantaneous current measured over time, divided by that time. It is NOT easy to measure for alternating currents!

Apparent power (VA) is the RMS voltage multipled by the RMS current. it is useful for calculating wire/fuse sizes etc.

In DC circuits, they are essentially the same.

The important thing is that you need to size circuitry for VA, not W.

[StuM]

Originally Posted by FionaJC

I had a teacher just like you, I proved him wrong more than once and he lost all credibility. I have an Electronics engineering degree, a PhD in computer science, run two companies and he is still a teacher. He also told me that women shouldn't do science, we don't have the brains for it.
You remind me of him a lot. Youre real name isn't Richard Edwards is it?

It always amuses me when certain people tout their qualifications and then resort to ad hominems when they can't argue the salient points. You're the second one to do it in as many days.