Please use the correct units.

Having been trained as an electrical engineer many decades ago, I regularly find myself grinding my teeth and attempting to pull out what remains of my hair. Why? because people keep referring to such things as 8.2kW batteries, 3.6kWh hybrid inverters, annual electricity consumption of 9,000kW etc.

PLEASE STOP IT!!!

Power is measured in Watts, kW etc.
Energy is measured in Watt hours, kWh etc.
Batteries store energy.
Inverters and solar panels convert power.

For the sake of my teeth and hair, can people please try to use the correct units.

Eyeroll - For the sake of MY teeth and hair:
Everyone knows what everyone means...if it bothers you that much then phone off and go for a walk.
This is from another electrical engineer.

Trouble is, it isn't always clear what people are talking about. This thread, which you just replied to is a case in point. Was the OP referring to a charge rate of 2.6kW or a capacity of 2.6kWh? I'm not at all sure from the post...

mrand31 they are sometimes a chew but given this is often the first time people are even hearing about some terminology I cant point fingers anymore than when I myself flail around trying to get words right in Spanish. You get the gist or in this case I put my Sherlock Holmes hat on and deduced -

The title states - 2x2.6 batteries
They mention it shows as 2x 2.6kWh packs on the portal. So that confirms above.
The portal doesn't report the max power rates per battery pack anywhere (which would be good if it did as I suspect they would not need an answer then)
The portal & app don't show you anywhere a %SOC = kWh available in the pack (as I had to write my own thing to do that a few months back) so that determines that they are likely talking about the % power sliders and actual power in & out the pack not their capacity.
The portal / graphs don't show power charge/discharge as a % of the power available to the system either (as again I did my own thing for that) so that's another clue towards the op talking about power sliders.

Not massively useful but the 3.6 Gen 2 has a max Charge Rate of 3.6kW at 100%, so its basically one of two things i can think of:

They actually have a Gen 1 Hybrid and don't know it (as they are the only ones you can confuse them with and end up with 2.6kW charge rates.)
They have a Gen 2 but the small battery packs are limiting the Power in/out to a lower value than they expected. (Which is what I believe is happening)

The thing is that not everyone is trained electrical engineer. So we make mistakes and sometimes those mistakes are blindly obvious to those with the necessary trading, but not to those without..
We are all on here to learn new things, so why not help out by sharing some of your training instead of being condescending?

Also, never forget that you are as ignorant as the rest of us about 99.99999999% of human knowledge outside your particular specialist subject. Ask me about astrophotography or the workings of the Sun and I'll gladly share with you. I'll also try not to point and laugh when you mix up your angstroms and your wavelengths. 😆

I'm not trying to be a nob, I just think people have enough on their mind with a new system when it's not working as they expect (which is often when you see questions on here and then never hear from them again once resolved) than worrying about getting everything perfect. If it is genuinely confusing then yeah sure a follow up to explain "did you mean"...
Maybe it's the heat, I'm a bit grumpy today and I'm not an admin or anything so what I think/say is no more valid than anyone else, maybe I'm the only one not that fussed by it!
(Other than at work, where it does very much matter) What do / did you work on/with by the way. I'm on Power Stations, Grid and stuff like that.

mrand31
There's no such thing as a stupid question. There are, however, plenty of stupid answers....

hoggy Started off expecting to design large rotating machines. The downturn of the early '80s caused me to move a mile to the other site and be responsible for power measurements on steam turbine performance tests. Spread out to instrumentation, then programming when no one would/could write the programs I needed for my calculations. Went on to write data logging programs as well as the rest. CEGB and utilities in South Korea, Hong Kong, China and India. Moved on to rotor balancing. Finally gave up all contact with civilization and spent the rest of my career doing Unix, Windows and network system administration.

I know people get mixed up, but it's really not that difficult for anyone bright enough to care about their electric bills.

Zakalwe in regards to the workings of the sun, can you tell us how to turn it down a bit the next few days?

hoggy Bloody control rods are stuck...

But the majority of people know what people are on about regardless of the post if the incorrect unit used anyway.

Have a good Sunday people 😄

hoggy

Simple...wait until nightime and then chuck a big bucket of water on it....

hoggy isn’t that knob not nob? I understand that some people may get confused and think it’s means a 1000 nobs but I think you should use the right terminology. Hope that cheers you up! 🙂

The correct units for measuring energy are Joules. A Joule is a watt-second, so 1kWh = 3.6MJ. If battery capacities are correctly stated as 9.36MJ, 18.72MJ, 29.52MJ, and 34.2MJ there will be no confusion.

Please don't turn the Sun down yet, It's lovely outside!!

CARLMW haha probably. I suppose if you asked the guys at work I'd probably be a Mnob...

mrand31 hmm small world (I work for one of the many tentacles of Babcock) so we too pop up all over the place. Not quite as glamourous as it all sounds though is it? People think your down time is laying on a beach with a nice cocktail when in reality the plants are 99% of the time tucked out the way in some far corner with no amenities!
Had a pet rat on a job in Saudi for a few weeks & the luxury of an electric* shower in Egypt

*terms apply - actual electric shower may not be present but the live wires poking out the wall will be while you try not to die under the miserable trickle available.

As another Hons elec eng (used to design MW+ sized gas compressor induction motors and then tested 50MW and up turbo generators amongst other stuff etc.) I think you are on a losing wicket - without the kind of training we have had, confusing kW and kWh is inevitable. 😁

Rubikcube The Standard International Unit of Energy may be a Joule, but in his amazing book entitled "Sustainable Energy - without the hot air", Professor David MacKay's triumph was in using the units of kWh/d to make comparisons of energy sources versus energy uses that even a non-technical person could easily understand.

Sadly, David is no longer with us, having died at a cruelly young age but his book is available to read online or download with no charge or to purchase at around £20, I think. Very useful volume for your bookshelf (especially as background for Zoom meetings...)

https://www.withouthotair.com/

I should have added that I sympathise with all the various views expressed above, being an ex-electrical engineer.

wilfleek
Yabut would anybody, at all, claim to drive the 60 miles from Lands End to John O' Groats at 837mph?

😀

mrand31 I can forgive people for not getting terms exactly right. It's like the relationship between the capacity of a car fuel tank, it's mpg figure and the price/l of fuel. Some people (that's me) are obsessed with fuel economy (mpg) whereas most are just concerned with how much it costs to fill a tank (never mind how long it's going to last - time or miles) and others are only bothered about how far it will take them (also an EV-owner trait).

What irks me on hot sunny days is when the regulator says the Price cap to increase by £693 from April. Martin Lewis tries his best to explain what it means but from the people I know, they have no clue what a unit of electricity is. For years, I've had friends who go from smugness at their new reduced monthly direct debit to panic when they find out they haven't been paying enough for their usage.

Lets face it, there are people who can explain the difference between power and energy but there are too many out there who don't know how much a unit of their electricity costs them and have no clue about how much energy they use in a year. If people are talking about it, trying to learn, then I think as long as the answer uses the correct units, then people will learn. Ironic that the term "unit" in this context is used to "demystify" the kWh which by its very nature tells you all you need to know about what the measure is, as long as you understand SI units.

Darn it I I need several 'units' of ethanol!

Tim When it comes to cars and fuel economy, people also seem to fail to appreciate the effect of speed on their range too - moan about the price of fuel, then belt down the motorway at 90+ - Only because I'm a slight nerd and do a lot of driving on motorways, dropping from an indicated 75 to 70 makes about 5-6MPG difference in my car (About 10%) - Still working on getting 800miles from a tank - best so far is 787.

anglefire your absolutely right and I wish the silly WLTP measure they use, especially for electric cars made more sense! For example the how far the cars travel should have been expressed as a range eg. 30 to 70 mph = 211 to 145 miles. People just don’t get that this is the reverse of ICE cars because it’s all about wind resistance!

Personally I think the government should temporarily change the speed limit down to 60mph. That would reduce UK petrol consumption significantly so drive down prices. Of course this would harm VAT revenue so would never happen!

Blow that, I want the M'way limit increased!