Kwh

solaris

solaris

Joined
May 20, 2015
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Just spent 2 days on a Dutch site. Electric was 12 amp with a 4 kWh per day limit which we easily exceeded despite being out all day. In the real world what is a kWh and how does it equate to usage? Thanks
 
A kWh is one kilowatt used for one hour.
So,you need to know how much each device uses. LCD lights use next to nothing. Hair dryers use tons!
I’m sure an expert will be along soon to give you a more technical answer!:D;)
 
A 100watt light bulb will burn for 10 hours for 1 kilowatt
A 25watt TV will run for 40 hours for 1kilowatt.

Your battery charger could use half, or more, of your daily allowance if you have a few 12v appliances running for any length of time .

1kw in the UK costs around 16p

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Last edited:
A Truma heater could use 4Kwh in two hours.
 
Did your batteries need a charge... did you cook on a hot plate.... hot water on electric... they all add up..
 
We stayed just outside Oliva at Kikopark (just south of Valencia) for a few days in January. Their daily charges included a quota of electricity (5kwh through C&CC, 4kwhs when booking directly). Any use over the quota was charged at 0.60 euros per kwh. I carried out an experiment over three days to see how much of our daily quota we used. I left the fridge freezer on electricity but heated the van and cooked on gas. We used a small amount of electricity for lighting. The first day we used a little more than allowed but then only used 13kwhs over the three days. This little test demonstrated to me that, when the electricity is metered, we will use gas.
 
1 kWh is 1 unit of UK electricity and it doesn’t take long to consume 1 unit at home.
 
We were on 4Kw per day at Villasol, Benidorm. With gas heating and cooking, we averaged out at 3.7Kw daily usage........... with the AES Fridge freezer using most of that. :(

Cheers,

Jock. :)

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To put it in leisure battery terms, a 100Ah battery should produce roughly 0.6 kWh if discharged to 50%

(Battery Capacity (100Ah) x voltage (12v) = 1200w = 1.2kWh @50% = 0.6kWh)
 
Thanks all. Fridge on all time, heating in evening plus lights. Arrived around 4pm, one whole day, left 10.30 next day. Went 14 over limit at 0.5 Euro per kWh. Didn’t think to ask how daily limit works on part days. Something to be aware of next time
 
solaris said:
Thanks all. Fridge on all time, heating in evening plus lights. Arrived around 4pm, one whole day, left 10.30 next day. Went 14 over limit at 0.5 Euro per kWh. Didn’t think to ask how daily limit works on part days. Something to be aware of next time
Click to expand...

It'll be your heating that's done it if that's running off electric.

If we're on metered electric and need to run the heating we always run it on gas.
 
funflair said:
Fridge next to B all, heating if left on, silly boy.

Martin
Click to expand...
Sorry Martin. our fridge ( a omatic Tower ) uses 1.8kW per 24 hours. Our previous fridge was a Thetford Tower which used 2.2 kW per 24 hours.
We always run the fridge and heating on gas.
The only thing electric is the battery charger which gets turned on for a full day every 7 days if needed. The solar panels usually take care of the batteries anyway, but if dull and over cast for a week I give them a boost
 
Jaws said:
Sorry Martin. our fridge ( a omatic Tower ) uses 1.8kW per 24 hours. Our previous fridge was a Thetford Tower which used 2.2 kW per 24 hours.
We always run the fridge and heating on gas.
The only thing electric is the battery charger which gets turned on for a full day every 7 days if needed. The solar panels usually take care of the batteries anyway, but if dull and over cast for a week I give them a boost
Click to expand...
OK more than I thought actually, depends on ambient temp and door opening etc I guess, a few years ago we were in Spain on metered leccy and we managed with less than 3 kWh per day but I was running the fridge and a few other things on solar during the day.

Martin

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JockandRita said:
We were on 4Kw per day at Villasol, Benidorm. With gas heating and cooking, we averaged out at 3.7Kw daily usage........... with the AES Fridge freezer using most of that. :(

Cheers,

Jock. :)
Click to expand...


Did you have to refill your bulk tank whilst there Jock or use another gas source?
 
CazPaul said:
Did you have to refill your bulk tank whilst there Jock or use another gas source?
Click to expand...
I used a Spanish Repsol Propano cylinder Paul, keeping my bulk tank contents in reserve. It was cheaper to buy gas in cylinder form anyway, going through one every week to ten days, until the weather warmed up. :)

Cheers,

Jock. :)
 
solaris said:
Just spent 2 days on a Dutch site. Electric was 12 amp with a 4 kWh per day limit which we easily exceeded despite being out all day. In the real world what is a kWh and how does it equate to usage? Thanks
Click to expand...

4kWh of electricity will cost you about 60p over here, so it's not a lot. A bit of a cheek to charge €2 for it! All the more reason to avoid using EHU for anything other than 12V under those circumstances. Gas is much cheaper, especially if you use forecourt LPG.
 
Wissel said:
To put it in leisure battery terms, a 100Ah battery should produce roughly 0.6 kWh if discharged to 50%

(Battery Capacity (100Ah) x voltage (12v) = 1200w = 1.2kWh @50% = 0.6kWh)
Click to expand...

Sadly your theory is a little bit out:

If you discharge the 12V battery to 6V [NOT ADVISED] then the average voltage is 9V.

100Ah x 9V = 900Wh = 0.9kWh

HOWEVER, hopefully it allows folk to get some sort of idea of how much ENERGY you can store in a standard "car-type" (lead-acid) battery.
It might help them to understand why you can't "store" a lot of electricity very easily: in financial terms, a £100 battery can store approx 15p worth of electricity!
With a typical charge/discharge life expectancy of 500 cycles, this gives £75 worth of electricity to carry around with you BUT of course, you also have to pay for that electricity.

So an outlay of £175 gets you £75 worth of transportable power.

[IF you discharge your battery to 6V every time, I doubt that you would get 500 cycles, so the figures just get worse.]

Electricity is often referred to as a "secondary" source of energy: you need a "primary" source such as oil, coal, gas to be burned to produce steam to turn turbines to turn generators to produce electricity: that is why running on gas is going to be cheaper than running on electricity (unless your electric is "free" eg solar, wind power, etc.)

One of the most amazing numerical facts is that 1kWh = 1 000W for 1 hour = 1 000W for 3 600seconds = 3 600 000J [joules].
This is sufficient energy to lift 1tonne (=1 000kg) to a height of approx 360metres near the Earth's surface (=7x height of Nelson's Column).
All for the cost of 16p!

Gordon
 
Not sure I understand what you mean @Rapido925M

The bit about 6v?

A normal 12v LB @50% discharge would be around 12.1-12.4v. Guess I'm missing something?

Regarding converting Ah to kWh, I just checked what I wrote in a calculator here:
https://www.inchcalculator.com/ah-to-kwh-calculator/

I get the result I wrote, so again guess I'm missing something obvious?

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Missing units can confuse.
50% is just a ratio, and needs to be qualified: 50% of capacity not potential (V).
 
Wissel said:
Not sure I understand what you mean @Rapido925M

The bit about 6v?

A normal 12v LB @50% discharge would be around 12.1-12.4v. Guess I'm missing something?

Regarding converting Ah to kWh, I just checked what I wrote in a calculator here:
https://www.inchcalculator.com/ah-to-kwh-calculator/

I get the result I wrote, so again guess I'm missing something obvious?
Click to expand...
I can’t see where 6v comes into the equation either but I guess the point is the same i.e. a battery has a more limited storage capacity than many realise.
 
Northernraider said:
My head hurts
Click to expand...
At the start of this thread I thought that I was starting to understand leccie after 65 years of ignorance.......................
Now I realise my confidence was ill-founded and I haven’t got a xxxxxxxx clue!
Has anybody brought a shotgun?:cautious::rolleyes::D

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two said:
Missing units can confuse.
50% is just a ratio, and needs to be qualified: 50% of capacity not potential (V).
Click to expand...

Like wot e sed!

I totally agree that 100Ah at 12 gives 1.2kWh.

IF discharged to 50% capacity and the voltage drops to 10V (rounded figures to make the maths easy!) THEN the average voltage is 11V
[(12 + 10) / 2 = 11 - apologies for trying to teach how to suck eggs!]

So the Ah to kWh conversion gives 1.1.

BASICALLY, what I was trying to say is that you cannot count it as a 12V battery if the voltage drops as it discharges: it requires a little more investigation to get an ACCURATE answer, but as a ball-park figure, 1kWh is about right for a lead-acid device.

[My mate has a 3kW inverter in his MH because his wife insists on using hair straighteners every morning. Fortunately, only for a few minutes because they prefer wilding to EHU sites!]

Gordon
 
Rapido925M said:
BASICALLY, what I was trying to say is that you cannot count it as a 12V battery if the voltage drops as it discharges: it requires a little more investigation to get an ACCURATE answer, but as a ball-park figure, 1kWh is about right for a lead-acid device.
Click to expand...
Then why use 6v when 12.7 - 12.9 is fully charged and 50% is 12.2 the logical figure to base calculations on would be 12.5v.
 
I know the original question wasn't about batteries but as we have gone off at a tangent wouldn't it be easier if we concentrated more on WH
*WH = AVAILABLE WATT X HOUR AT 20H RATE FROM A BATTERY, WITHOUT EXCEEDING ITS RECOMMENDED DEPTH OF DISCHARGE.

Then you would see that for example a Exide 100Ah lead acid battery has 650 available Wh where a 85Ah Gel battery has 950 Wh and a 100Ah lithium battery would have over 1000 Wh.

Looking at the figures reinforces the argument that not all batteries are equal.

Martin

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