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Discussion Starter #1
I have done some calculations to determine how long the Ampera might take to charge up from a discharged state.

There are a few assumptions:

- the battery is 15KWh but only about 10KWh is used as the battery management system stops it from being fully discharged or overcharged.
- grid voltage is 230VAC but this can vary (drop) quite a bit at peak times
- the supplied cable charges at 10A which is 2.3KW
- a home pod charges at 16A which is 3.6KW
- assumes battery is as discharged as the car allows

So on the cable at 10A it will need 11 / 2.3 = 4.7 hrs

On the home pod it will need 11 / 3.6 = 3 hrs

It will be interesting to see what times people are actually getting. Please post your charging times here but don't forget, times are only valid if the car has discharged to the point where it goes into ER mode or else the battery will still have useable charge remaining and the times would be valid.
 

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If I understand you then you've allowed an extra 1kWh for charging losses. The figures I found previously suggested it might be nearer 2kWh.

The other factor that I don't think you've allowed for is that the charging is supposed to be non-linear, so you'll reach 50% of charge in less than 50% of time. I think someone should try charging with a meter connected to measure current drawn against time to see how pronounced this is.
 

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Discussion Starter #3
Yes, I haven't been very scientific about it have I? :oops:

I think that the loses will be nowhere near 20%. The Leaf is about 10% and unless the Ampera charger/inverter are particularly inefficient I would expect something near the same.

You are correct of course... charging is non-linear but I was baseing my calculations on my experience with the Leaf which although might be quite different I would be surprised if it were radically so.

I will try to run my own tests once I get the car and post them here and if others could do the same it might build up a more accurate picture.

:)
 

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When we drove ours home the 1st time we used up all the battery, we pluged it into our pod ( http://www.pod-point.com/products-page/ (16A version) ) it took 4hrs (+/- minutes) to fully recharge the car.

During this time the car was taking approx 4kw of electric according to our usage meter.

Hope this helps

g
 

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Ampera will use up to 10kW of the battery's 16kW capacity. The battery will charge at a maximum rate of 3.3kWh. It'll take up to 12.6kWh of electricity to recharge, owing to loss in transfer/heat.

If charging with a 16kWh unit, it'll run at approx 15kWh

Hope this helps
 

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Discussion Starter #6
SP_66 said:
Ampera will use up to 10kW of the battery's 16kW capacity.
Don't you mean 10KWh of a 16KWh capacity?

The battery will charge at a maximum rate of 3.3kWh.
Don't you mean 3.3KW?

If charging with a 16kWh unit, it'll run at approx 15kWh
Sorry but I am confused by this last bit completely... can you explain please? It doesn't make any sense at all to me, sorry!

Is that you Simon Prior? If so, you weren't typing this on your phone were you? I am having similar problems getting my phone to type what I want it to type... stupid predictative text! :eek:

Could you clarify when you get to a keyboard as I am a little confused. :?

Thanks :)
 

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Discussion Starter #8
Yes, thanks for that.

SP_66's post just doesn't make any sense because he is using KWh where KW should be used and KW where KWh should be used. The last bit just doesn't make any sense to me at all!

I suspect it was typed on a phone :?:
 

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Ampera Technician said:
kWh = kW per hour
You've got that backwards. kWh is kilowatt hour, i.e. power multiplied by time.
kW per hour would mean kilowatts divided by time which isn't a useful measure of anything.
 

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Discussion Starter #10
I think this was why I was being so picky when saying I didn't understand the SP_66 post.

KW (kilowatts) is a measurement of power. It is the equivalent to horsepower.

The Ampera has a 80hp or 59KW petrol motor driving a 74hp or 54KW generator and a 111KW or 150hp electric motor.

You can see how KW and HP both measure power and you can convert one to the other easily.

KWh on the otherhand is a measurement of energy. For those that don't understand the difference I like to explain it like this:

Imagine a 2kg bag of sugar sitting on the floor. You want to move the sugar to the table. It will take a certain amount of energy to move 2kg up to table level. A mouse could do it easily a little at a time. Or you could do it all at once. It requires the same amount of energy to do it regardless of whether it is you our the mouse but you have more power so can do it more quickly.

So power is the energy used in a certain amount of time.

So, relating this back to the Ampera...

Batteries store energy so they are measured in KWh. The battery on the Ampera is 16KWh. This roughly means it stores enough energy such that using it at 16KW it will last an hour.

The charger on the car takes energy and puts it into the batteries at a certain rate or power. 2.3KW using the supplied cable or 3.3KW using a home pod or a type 2 cable on a public post.

This is a complicated subject for a lot of people but it is something that Ampera owners will need to understand the basics of if they are to get the best from the car.

If this really confuses you then you are welcome to PM me and discuss it in private or on the forum if you prefer.
 

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Sorry to be a pedant but the correct unit of power is kW not KW and of energy is kWh not KWH or even KWh! This is one of my hobby horses. The other is how few people - even in this jubilee and olympic year - seem to know which way up the Union Flag should fly!
 

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Discussion Starter #12
Well... I was picked up on another forum for using kWh :eek: Since then I have used KWh.

I always have known it as kWh but when I was corrected I didn't bother to check.

You are absolutely right... Sorry


PS I think that one of the biggest benefits for us all of a forum like this is that we can discuss these kinds of things and so we all learn. I don't consider you a pedant at all... just someone, like me, who wants to get things right! Thank you ;)
 
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