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Discussion Starter #1
Last week before we left london for the Lake District we were seeing 180-190 miles available. After 8 or so rapid charges going there and back our maximum charge got lower and lower, and now shows a piss-poor 133 miles after a slow overnight charge at home. We expected a little rapidgate, but not this much - is this loss of range correct, will it return or should I worry?
 

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It's based on your recent driving style. Drive slowly and it will go up. Drive along the motorway and it will go down. You've not lost any capacity in the battery. Just the car is expecting you will continue to drive fast and as a result predicts a lower range.

This isn't anything to do with rapidgate. Rapidgate was regarding rapid charge speeds getting slower with each charge session, and was mainly regarding the Nissan LEAF.
 

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Seems about right given all your recent journeys have been at motorway speeds.

After a few days of driving around London at much lower speeds, it'll go back up.
 

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I mostly agree with these assessments. Your recent driving style is what determines the GOM (Guess-O-Meter) range. If you performed 8 back to back DCFC sessions you heated up the cells quite a lot, and any reduced charge rate you observed (rapidgate) confirms this. Keeping the pack very hot for extended periods of time will lead to cell degradation. After that sort of punishment, you may even be able to measure the capacity loss if you are able to be accurate in your calculations. I'm not saying you lost a kWh or two, but it is certainly possible you lost a few tenths of a kWh usable capacity. If you start keeping a log of your travels with accurate consumption data, you will be able to see how the health of the pack declines over time.
 

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Agree the GOM is just reflecting your recent driving conditions. As well as your average speed, hills make a big difference. Lake District has some, London really doesn't.

Today I drove 121 miles from near Dundee to near Inverness. Left with 100% charge, arrived with 7 miles on the GOM. And that was generally quite slow and steady driving thanks to the A9 being full of campervans and no aircon/heating because it really wasn't needed. Without the hills I'd have expected a good (real world) 150 miles in todays conditions.
 

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Discussion Starter #6
It's based on your recent driving style. Drive slowly and it will go up. Drive along the motorway and it will go down. You've not lost any capacity in the battery. Just the car is expecting you will continue to drive fast and as a result predicts a lower range.

This isn't anything to do with rapidgate. Rapidgate was regarding rapid charge speeds getting slower with each charge session, and was mainly regarding the Nissan LEAF.
the problem is the average 4.5kw useage is the same. In london the past few months I’ve had a very similar average, on motorways and around londons slower roads. on this 500 mile trip I averaged 4.5, didn’t go over 70 and generally didn’t push the battery apart from getting lower and lower maximum ranges after successive rapid top ups.
 

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the problem is the average 4.5kw useage is the same. In london the past few months I’ve had a very similar average, on motorways and around londons slower roads. on this 500 mile trip I averaged 4.5, didn’t go over 70 and generally didn’t push the battery apart from getting lower and lower maximum ranges after successive rapid top ups.
Multiple Rapid charges have no effect on your range. Your M/way speeds have an effect on the GOM predicting that you will not get 180 miles from the e-Golf. I drive 70 miles daily commute, regularly driving at 60-70 and I only see 130 or less every day for a full charge. And I never rapid charge the car as I don't need to..
 

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Any lithium ion cells degrade at elevated temperatures. Hence, why most EVs sold new today have active thermal management. Multiple rapid charges make the pack very hot and cause accelerated degradation on the e-Golf (and Leaf) because these cars have no active thermal management. You may not notice the degradation in the short term but it is still happening. Even Tesla recommends not to supercharge if you don't need to because of accelerated battery degradation. If you have never rapid charged your car, you are protecting cells from high charging temps and thus reducing rate of degradation.

Avoid elevated temperatures due to rapid charging as well as high ambient temps, if you can. The pack can not tell the difference between high temps caused by a hot climate or by high speed driving combined with repeated rapid charging. I recently saw a comment by e-Golf driver who lives in Arizona - his 2015 e-Golf pack at 63,000 miles has lost 32% of original capacity thanks to very high ambient temperatures.
 

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I really hope that the e golf would have a similar story as this.. I know that the leaf is somehow easier to modify battery wise..

 

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Discussion Starter #10
Any lithium ion cells degrade at elevated temperatures. Hence, why most EVs sold new today have active thermal management. Multiple rapid charges make the pack very hot and cause accelerated degradation on the e-Golf (and Leaf) because these cars have no active thermal management. You may not notice the degradation in the short term but it is still happening. Even Tesla recommends not to supercharge if you don't need to because of accelerated battery degradation. If you have never rapid charged your car, you are protecting cells from high charging temps and thus reducing rate of degradation.

Avoid elevated temperatures due to rapid charging as well as high ambient temps, if you can. The pack can not tell the difference between high temps caused by a hot climate or by high speed driving combined with repeated rapid charging. I recently saw a comment by e-Golf driver who lives in Arizona - his 2015 e-Golf pack at 63,000 miles has lost 32% of original capacity thanks to very high ambient temperatures.
thats interesting to hear. By comparison, an ICE would lose some efficiency after 5yrs/65k but nothing as bad as that. However I’d still bet the EV had less maintenance costs perhaps?

@buck eejit ok good to know. I think the problem starts with me not knowing how GOM is calculating! Correlation not causation seems to be my error.
 

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I wouldn’t worry too much @Snax, the e-Golf has a pretty low stress battery setup, high quality pouch cells, and a good BMS.

Even rapid charging is only just over 1C, and max acceleration is around 3C, and you can’t keep that up for long either.

I first ‘stressed‘ my battery when I’d had the car a couple of weeks, coincidentally on one of the hottest days of last year and also on a trip that took me through the Lakes. It wasn’t Arizona hot though, admittedly.

21k miles on, and with weekly rapid charging amongst the slower home charges, it’s still hitting the numbers range and charge rate wise, it just gets on with it. It’s an unremarkable electric car in many ways is the e-Golf, but it’s one of the things I like about it! If it wasn’t for the plugging in bit, I’d forget it was electric at all.
 

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The e-Golf has PHEV2 prismatic cells, not pouch cells.
You are missing the point when you mention C rate. Lithium ion cells do not care how they get hot, and if you can get a 50 C pack temperature by charging at 1 C, the cells still get damaged.
Living in a mild climate, like the British Isles, high pack temps are less of a concern than cars that “live” in hotter climes, but repeated 50 C soaks will cause degradation. This is physics and chemistry and not worrying has no impact on reality. Back to back DCFC sessions combined with high speed driving is a very effective way to get a hot pack. All the BMS can do is cut power to reduce Joule heating, it can not actively cool, so instead of preventing damage the e-Golf BMS can only mitigate damage.
 

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Discussion Starter #13
It’s returned as predicted today to a much happier 170. I think what’s frustrating, and which I was aware of going in, is the reality of not being able to predict what kind of road I may use day to day, and so the car can’t either. And I think therefore that another 50 miles range would make things a lot easier. It’s still the best car I’ve owned, rocket milkfloat
 

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@Snax I think you are concerning yourself too much with what the GOM states. Think of it like that: the GOM is an educated guess based on how much energy you have in the battery. That energy hasn't changed! It is still the same. As you become more experienced, you will see why people prefer to have a percent display, as they become better at judging available range.

Anyway enjoy the car!
 
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