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Discussion Starter #1
I purchased a new 225XE in November 2019 the charging time using the standard supplied charger from empty to 100% charge was originally around 3.5hrs. This charge time has over the last 2 weeks started to increase to about 5hrs.

. The amperage drawn by the feed to the charge is constant when charging at 9.5amp (measured using a clamp meter on the positive feed to the charger). My household electric monitor confirms this and shows 2.2kw when charging.
The car is set to MAX charge rate.

Anyone any ideas why it is now taking 5hrs rather than the expected 3.5hrs?. or anyone with a 225XE getting long charge times(5HRS) with the standard charger?

The temperature outside during the last week (when is has been taking 5hrs ) is warmer than it was in Dec when it was taking 3.5hrs. Sodon;t think it is temperature related.
Its now nearly as cheap to use petrol instead of charging it at all!. -- 2.2kw for 5hrs = 11kw @ 14p KW = £1.54 for 20 miles driving!.
.
 

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Hi and welcome.

if you unplug the car after 3.5 hours charging, what % does the battery capacity read-out say? It's odd that the car is actually drawing 9.5A but taking well over the normal charge time.

A tip I got when I first joined here from i3 owners is, don't unplug the car after 100% charge is reached, unless you need to drive the car. Apparently once the battery is at 100%, keeping it plugged in puts a 'float' charge into the battery and helps to equalise charge across all of the cells in the traction battery. Without this, some cells drain faster than others and can cause overall capacity and range to drop faster.

So I invariably leave mine plugged in overnight - it's usually fully charged by 10pm but remains connected until 8am next morning. Battery range hasn't altered in my 2.5 years ownership (I also use the granny cable and charge from a 13A socket in my garage).
 

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Discussion Starter #3
Hi, thanks for the reply.
I haven't actually unplugged it after 3.5hrs but have monitored it via the BMW connected app at various stages of the charge. The charge rate rises proportionally, so after 3.5hrs it will be about 70% (5/3.5 x 100) .

Good point about leaving it on charge even after it is 100% --- I have been leaving plugged in and switched on but only because I haven't bothered to go out and disconnect it. I am going to the Octopus GO tariiff, when they get around to updating my smart meter, when I am on that tarriff I will set it to swicth on\off during the cheap rate (00:30 - 04:30) . I will do this via a WIFI SONOFF device that will control the supply to the charger. I'll set a timer schedule to start at 00:30 but will now set the end time later than 04:30 so it stays on float charge.

Update on the 5hrs charge time --- I emailed my dealer about it and they have now got back to me and booked the car in in 2 days time for investigation. They didn't say anything about what it might be.
I'll update the result here after it's been in.
 

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Discussion Starter #4
Dealer has the car in and says 5hrs is the correct time for it to charge on the standard charger (with car set to MAX).??
I have queried how a 7.7kw battery can need 2.2kw for 5hrs to charge from 5% to 100%.
Would like to hear anyone elses person experiences of their charge times using the standard supplied charger please.
(unless my july 2019 225ex actually has the latest 2020 10kw battery pack it doesn;t make sense to me!)
 

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I don't know exactly, but would make a few observations:
  • what voltage do you have going to the "charger"? You may not be pulling 240V and hence less than 2.2 kW particularly if there is a power factor caused by the car involved (the voltage and current out of phase).
  • there are loses in the car when it converts from AC to DC. At less than full charging rate (i.e. the granny charger rather than the mains) efficiency drops considerably so you may have loses of >20% so the DC may be less than 1.6 kWh
  • certainly in the case of the LEAF24 (older tech, different manufacturer obviously) it can take nearly an hour for the battery balancing if there is a weak cell. During battery balancing the current drawn is reduced - do you see this with your data?
  • putting this all together 5 hours doesn't seem totally unreasonable.
 

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Discussion Starter #6
I don't know exactly, but would make a few observations:
  • what voltage do you have going to the "charger"? You may not be pulling 240V and hence less than 2.2 kW particularly if there is a power factor caused by the car involved (the voltage and current out of phase).
  • there are loses in the car when it converts from AC to DC. At less than full charging rate (i.e. the granny charger rather than the mains) efficiency drops considerably so you may have loses of >20% so the DC may be less than 1.6 kWh
  • certainly in the case of the LEAF24 (older tech, different manufacturer obviously) it can take nearly an hour for the battery balancing if there is a weak cell. During battery balancing the current drawn is reduced - do you see this with your data?
  • putting this all together 5 hours doesn't seem totally unreasonable.
Hi thanks for the reply, the 2.2kw draw is measured on my household supply monitors x 2 (minus the normal draw of other items at the time) . I can switch the charger on\off remotely and watch the KW change when the charger is on (e.g. ny current draw is showing as 0.2kw, switch the charger on and it goes up to approx 2.4kw).
Have also measure the amperage on the input to the charger and this was 9.5amp.
Haven't noticed any substanstial drop in the current draw when it gets near full charge but I will check that more when I get the car back (if BMW don;t have an answer!) .
Never thought of the current loses in the charger and in the car when charging but should they be as much as needing 11kw input to charge a 7.7kw battery from 5% to 100% ?. Sounds a big waste of energy if it is doing that.
 

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It seems that the 10 kWh (8.8 kWh available) cars were delivered from August so maybe yours is one of these? that might mean 1.8 kW from your charger which is totally believable.
 

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Discussion Starter #8 (Edited)
It seems that the 10 kWh (8.8 kWh available) cars were delivered from August so maybe yours is one of these? that might mean 1.8 kW from your charger which is totally believable.
I'm asking the dealer if he can check what battery it has but youre right, having a 10kw battery would explain it.
I bought it new in Nov 19 but it had a build date on the VIN decoder of July 19. I did query it with dealer before collection as I wasn;t too pleased when I found out that a larger capacity one was coming out, The dealer was adamant there was nothing on the official BM dealer site about any 10kw upgrade being available or when it would be. I nearly pulled out of the deal as didn't like the idea of buying an "old" model. Be ironic if it turns out it does have the latest battery. With buying it in Nov I haven't driven it in warmer weather but get around 20 -24 miles on electric now. Don't know if that gives an iindication of it have the larger battery??. What do other people get on purely electric at this time of year??, I need to do a search don't I :) .
 

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I have the 1st Gen battery, mine takes about 3.5 hours from 10% to full from a standard 240 3 pin charger. Electric range currently showing 18 miles
 

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Discussion Starter #10
I have the 1st Gen battery, mine takes about 3.5 hours from 10% to full from a standard 240 3 pin charger. Electric range currently showing 18 miles
Thanks for the info. , that sort of backs up my speculation now that mine may have the later 10kw battery. 18miles +25%extra (quoted for the 10kw battery) = 22.5miles , mine currently shows 26miles after a full charge but actually does about 22 on the mile ometer when checking.
I'm waiting to see if the dealer can find out what is supposed to be fitted to it. Don't think anyone knows how to find out :) .
 

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Cold weather? It will be trying to heat the battery as part of the charging and that will increase the time by quite a bit.

Also if you have pre-conditioning turned on it will have to recharge the battery after as it draws more than the brick can supply. But that wouldn't explain it being proportional.

But if it's a 10kW battery then that would be the simplest (and from your PoV best) explanation.
 
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Mine's also a 1st gen with the original 7.5KW battery, and it takes 3h15m from around 10% to 100% charge. I suspect you DO have the 10KW battery if yours does 20+ real-world miles on electric-only in the current ambient temps.

The best I ever got out of mine was 18 miles in ambients of 20C, bimbling on open country roads at 45mph. Yesterday, when the ambient was 10C, I did 10 miles and had 25% charge remaining.
 

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Doh should have thought of this earlier.

The co2 emissions for the 2nd Gen battery are 52 g/km for the 17 inch, 57 g/km for the 18 in wheels. The 3rd Gen Battery values are 42 g/km for 17 inch and 44 g/km for the 18 inch wheels.

So check your v5 and see what value it has for emissions.
 

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Discussion Starter #15 (Edited)
Doh should have thought of this earlier.

The co2 emissions for the 2nd Gen battery are 52 g/km for the 17 inch, 57 g/km for the 18 in wheels. The 3rd Gen Battery values are 42 g/km for 17 inch and 44 g/km for the 18 inch wheels.

So check your v5 and see what value it has for emissions.
yes, V5 shows 44g/km (it has 18 inch wheels). So good news it is the 3rd generation 10kw battery.

Dealer has today also confirmed it by obtaining a printout from BMW showing that the VIN shows a 30ah battery. Not sure how 30ah relates to it being a 10kw pack but dealer says old ones are only 25ah.
Need to get a fast charger next to cut down the full charge time !.

Thank you to everyone for the help and advice. Think myself (and particularly the dealer :) ) have learned a lot about charging etc.
 
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