Battery percentage, Ah or kWh? Battery degradation if charged 100 %?

[jallejulius]

Hi!
I just got my MG5 and I'm very happy so far. I have two questions:
1) Is the battery percentage showing it's value based on remaining Ah or kWh?
2) Will the battery degenerate over time if I always charge up to 100% or does this car have a built in protection for degradation even if I charge up to 100% every time?

Thank you very much!

 

[weedavemac]

Well done on getting your new car.

Re your questions....

1. Think it is kWh but somebody will be along soon to confirm.

2. This question will result in a myriad of different answers. All I will say is that in my case I charge to 100% every night and so far the state of health (SOH) of the battery, after approx 25,000 miles is 100%. However, if you are charging to 100%, don't leave the car unused for a period of time.....that is generally acknowledged to be bad for the battery.

Finally, enjoy the car.

 

[Gomev]

Hi!
I just got my MG5 and I'm very happy so far. I have two questions:
1) Is the battery percentage showing it's value based on remaining Ah or kWh?
2) Will the battery degenerate over time if I always charge up to 100% or does this car have a built in protection for degradation even if I charge up to 100% every time?

Thank you very much!

Re 1, probably kWh, everything for EVs is kWhs, never heard of Ahs being mentioned anywhere.

Re 2, do a quick search and you will find many a thread covering this in detail with multiple views.

Welcome

 

[Jomarkh]

Welcome,
I would say that percentage is in kWh, I aim for 2 miles for 1% but I have an SR.
I charge to between 80-90% as I need 70 miles for my commute and then battery balance once a month.
Enjoy your the ride?

 

[Gomev]

In fact thinking about it, a percentage is a percentage is a percentage, it doesn't matter what it is a percentage of.

 

[Petriix]

Hi!
I just got my MG5 and I'm very happy so far. I have two questions:
1) Is the battery percentage showing it's value based on remaining Ah or kWh?
2) Will the battery degenerate over time if I always charge up to 100% or does this car have a built in protection for degradation even if I charge up to 100% every time?

Thank you very much!

1) It's percentage of overall usable capacity, which can be expressed in AH and Volts or kWh (or joules etc). As it's a percentage it doesn't require any further clarification and it would be nonsensical to attribute it to something like kWh.

2) Yes, the battery will degrade over time and lose some capacity. Unless there's a cell failure, this will result in something like a 10-30% loss of useable capacity over 10 years (educated guess).

• If you want to keep to the lower end of that loss then you can minimise the stress on the battery by generally trying to charge and discharge as slowly as possible, keep it as close to the middle of the voltage range as you can, and avoid letting it get too hot. That means accelerating gently, minimising rapid charging, parking in the shade, only charging to full once per month or just before a long journey etc.
• If you don't mind about it hitting the higher end of that loss then rapid charge every day, keep it fully charged, accelerate hard all the time etc.
• If you just use it normally as you see fit then it will likely end up somewhere in the middle of that range.
• Whatever you do, the results of your charging routine will not become apparent for a couple of years in which time the degradation will likely all be hidden in the unusable buffer of the battery.

 

[Prof1967]

9000 miles in 12 months regularly charging to 100 per cent and at the annual service SOH was quoted as 100 per cent so no obvious degradation so far.

 

[DuracellBunny]

Welcome,
I would say that percentage is in kWh, I aim for 2 miles for 1% but I have an SR.
I charge to between 80-90% as I need 70 miles for my commute and then battery balance once a month.
Enjoy your the ride?

My GOM gives me the same, 2m/1% but mine is a LR, half of my commute is on the motorway and I get 3.5m/kw