First home charge - numbers dont add up....

Faults and Technical chat for the Jaguar I-Pace
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51mes
Posts: 168
Joined: Sat Aug 24, 2019 5:26 pm
Location: Cumbria /UK

First home charge - numbers dont add up....

Post by 51mes » Tue Nov 12, 2019 4:03 pm

I'm sat here doing my first home charge.

Pod point charger - using the 3M jaguar cable (and originally my 10M cable ordered from t'web).
I dont seem to be able to exceed 7% per hour according to incontrol.

This ties up with WattCat which reports +20m/h (5.5Kw)

However my clamp meter is reporting about 7.2Kw being consumed.
this ties up with the fact Podpoint is saying it has supplied ~6.9KW/hr.

However the two sets of numbers dont tie up....If This is a 20% power drain somewhere something is wrong, or am I getting the numbers wrong.

I started about 50% SOC and am now at 85% - heading out tonight for about 50-60 miles, then stupidly early in the morning for an 80 mile round trip, so topping up .
MY20 (Nov19) I-pace SE |AIR|Pan Roof|Light Oyster 10 way Heated Seats I Caesium Blue| 18" 5055 wheels
Infotainment 20C + Telematics 19.2 + H264 + H280| Podpoint 7Kw+ ohme cable for Octopus Agile charging.https://share.octopus.energy/sky-ape-579

*****
Posts: 1904
Joined: Tue Nov 06, 2018 5:46 pm
Location: Forest of Dean. UK.

Re: First home charge - numbers dont add up....

Post by ***** » Tue Nov 12, 2019 4:08 pm

The car uses quite a bit of power that is given to it to warm up the batteries during the charging process. There will be losses in the AC/DC converter also.

kermit68
Posts: 464
Joined: Sat Sep 15, 2018 1:06 pm
Location: Rome / Italy

Re: First home charge - numbers dont add up....

Post by kermit68 » Tue Nov 12, 2019 6:22 pm

Chewy wrote:
Tue Nov 12, 2019 4:08 pm
The car uses quite a bit of power that is given to it to warm up the batteries during the charging process. There will be losses in the AC/DC converter also.
But the charging process shouldn't warm up the battiery itself? I mean, at the beginning of charging, with temprature less than 30C, probably the car is going to use some energy to warm up the battery. But after some time the battery should be warm enough and we should see a rise in the charging rate that I never saw in my experience. Also, I totally agree that AC/DC convertion efficency is not 100%, but a loss of 20% sounds a little bit too much.
Personally I think that such numbers, as others coming from Jaguar API, cannot be taken as precise values. We can't get a reasonable and stable value on tire pressure, why we should be so confident about charging rate?
MY20 Yulong White SE, 20", air suspension, privacy glass, black pack and other fine stuffs

*****
Posts: 1904
Joined: Tue Nov 06, 2018 5:46 pm
Location: Forest of Dean. UK.

Re: First home charge - numbers dont add up....

Post by ***** » Tue Nov 12, 2019 6:52 pm

kermit68 wrote:
Tue Nov 12, 2019 6:22 pm
Chewy wrote:
Tue Nov 12, 2019 4:08 pm
The car uses quite a bit of power that is given to it to warm up the batteries during the charging process. There will be losses in the AC/DC converter also.
But the charging process shouldn't warm up the battiery itself? I mean, at the beginning of charging, with temprature less than 30C, probably the car is going to use some energy to warm up the battery. But after some time the battery should be warm enough and we should see a rise in the charging rate that I never saw in my experience. Also, I totally agree that AC/DC convertion efficency is not 100%, but a loss of 20% sounds a little bit too much.
Personally I think that such numbers, as others coming from Jaguar API, cannot be taken as precise values. We can't get a reasonable and stable value on tire pressure, why we should be so confident about charging rate?
Unfortunately, Jaguar don't tell us exactly what is going on - but it is believed that the battery is "conditioned" during the charging process to ensure it is at the optimum temperature during charging - this can be heating and/or cooling. If you put in a "Departure Time" the BMS will additionally ensure that the battery is at its optimum temperature for your departure time. 20% of 7kW is 1.4kW, not exactly a lot to keep the battery at a constant temperature during charging.

As far as number coming from the Jaguar API - I would take them with a pinch of salt. I have seen the APP report as much as 13% when the battery is low - This is clearly nonsense.

51mes
Posts: 168
Joined: Sat Aug 24, 2019 5:26 pm
Location: Cumbria /UK

Re: First home charge - numbers dont add up....

Post by 51mes » Tue Nov 12, 2019 11:01 pm

Well,

I will See how things progress, had a great run out tonight Ulverston to Ambleside via Bo'ness, then back via conniston as the lake road was closed.

44 miles in 4C temps wet and hilly/windy roads with heating, heated seats and lights took 50 miles of range. Plenty left for Lancaster and back tomorrow. Looks like I will charge again thursday/Friday.

I know the numbers are not accurate, but at a high level was thinking 20% was a lot - a smart tarrif might be looking more attractive than Bulb's standard rate at that point.

S.
MY20 (Nov19) I-pace SE |AIR|Pan Roof|Light Oyster 10 way Heated Seats I Caesium Blue| 18" 5055 wheels
Infotainment 20C + Telematics 19.2 + H264 + H280| Podpoint 7Kw+ ohme cable for Octopus Agile charging.https://share.octopus.energy/sky-ape-579

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