Is it best to charge little and often or max charge when needed?

BeekeeperMG5 said:
Is it best to charge little and often or max charge when needed?
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It depends what you mean by 'best'...

There are some (arguably very minor) efficiency gains by not charging to full (energy lost to heat when balancing the battery and through lack of regenerative braking when fully charged).

Battery degradation is highest at the extreme ends of full and empty and, while the battery management system (BMS) protects the battery from much of this, it's advisable not to leave the car fully charged for extended periods. MG themselves advise never to leave the car below 20% or below 50% for long periods.

Generally, the slower you charge and the less you charge at the very top or bottom of the battery voltage, the less damage you will do. Rapid charging all the time will definitely shorten the battery life.

Many people prefer the convenience of just plugging in when they get home each day and always having their full range available. I, on the other hand, like to keep space to accommodate free solar charging (by not charging from the grid unless I have to).

The actual long term effects of different battery management techniques are unknown and hard to measure.
 
The BMS won't let you charge to 100%.
On the ZS, when it says 100% on the screen, it's actually only at 97%, I would assume the 5 is the same.
 
Kithmo said:
The BMS won't let you charge to 100%.
On the ZS, when it says 100% on the screen, it's actually only at 97%, I would assume the 5 is the same.
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You're getting into semantics now. Read '100%' as 'the maximum the car will charge to'. It's still going to cause higher degradation at what you call 97% than at closer to 50%, it's a curve, not a binary thing. Whether the car having 94% of its original capacity after four years instead of 89% will bother you is another matter. Some of us plan for long-term ownership and like to take care of our incredibly expensive purchase.
 
Petriix said:
You're getting into semantics now. Read '100%' as 'the maximum the car will charge to'. It's still going to cause higher degradation at what you call 97% than at closer to 50%, it's a curve, not a binary thing. Whether the car having 94% of its original capacity after four years instead of 89% will bother you is another matter. Some of us plan for long-term ownership and like to take care of our incredibly expensive purchase.
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I agree, but isn't the 97% implemented by the BMS there for the protection of the battery anyway ?
 
Kithmo said:
I agree, but isn't the 97% implemented by the BMS there for the protection of the battery anyway ?
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Yes, the battery would be utterly destroyed by charging regularly to actually full or discharging to totally empty so there is an unknown size buffer at each end of the cycle. However, degradation will still be higher at both ends of the usable part of the battery voltage range.

Obviously use the full range when you need to, but avoid unnecessary charging at higher states of charge; charge as slowly as practical, limiting rapid charging to only when needed; charge it back up to at least 40% as soon as possible after you take it below 20%; and don't leave it sitting around over 80% or below 20% for more time than necessary.
 
I see estimates of the useable battery size of between 48.8 & 49.9 so does this mean its only ever charged to between 93 & 95%?
 
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aquarg said:
I see estimates of the useable battery size of between 48.8 & 49.9 so does this mean its only ever charged to between 93 & 95%?
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Well, sort of... The car calls it 100% and won't let you charge it any more, so it's best just to think of it as being a ~ 49kWh battery that goes from 0-100%.
 
Petriix said:
It depends what you mean by 'best'...

There are some (arguably very minor) efficiency gains by not charging to full (energy lost to heat when balancing the battery and through lack of regenerative braking when fully charged).

Battery degradation is highest at the extreme ends of full and empty and, while the battery management system (BMS) protects the battery from much of this, it's advisable not to leave the car fully charged for extended periods. MG themselves advise never to leave the car below 20% or below 50% for long periods.

Generally, the slower you charge and the less you charge at the very top or bottom of the battery voltage, the less damage you will do. Rapid charging all the time will definitely shorten the battery life.

Many people prefer the convenience of just plugging in when they get home each day and always having their full range available. I, on the other hand, like to keep space to accommodate free solar charging (by not charging from the grid unless I have to).

The actual long term effects of different battery management techniques are unknown and hard to measure.
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Best, as in best for the batter life.
 
The thermal management of the battery has a far bigger impact on longevity, so between that and the BMS the battery is pretty well looked after. But if you want to get the ultimate life then try not rapid charging at very low or high SOC. I would favour a little and often, keeping somewhere in the range of 50% - 80%. But then I tend to do lots of small journeys over 1 or 2 weeks, then a couple of long trips. So charge to 100% and rapid charges for the trips, and granny charge for the weekly charges. Ideally using a balance charge to get the 100%.

Probably nothing to get too anal about though.
 
JohnB said:
The thermal management of the battery has a far bigger impact on longevity, so between that and the BMS the battery is pretty well looked after. But if you want to get the ultimate life then try not rapid charging at very low or high SOC. I would favour a little and often, keeping somewhere in the range of 50% - 80%. But then I tend to do lots of small journeys over 1 or 2 weeks, then a couple of long trips. So charge to 100% and rapid charges for the trips, and granny charge for the weekly charges. Ideally using a balance charge to get the 100%.

Probably nothing to get too anal about though.
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And obviously don't forget to balance (charge to full and leave it plugged in for 3 hours or so) at least once a month.
 
C6MFC said:
How do you know the car is balancing do you need a smart meter
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When the car is performing a charge, the MG logo badge on the grill will "Pulse" in and out, very slowly.
When the car has entered the "Balancing" stage, the MG logo badge will change to displaying a constant, low glow from the badge.
When the balance is complete, the car will automatically end the entire process altogether.
 
pjmuk said:
Not on the MG5 I'm afraid! You have to check the display screen in the car as above!
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Bit "Pants" that idea ?.
I do like the idea that you can clearly see what stage the car is at, from a distance on the ZS EV.
A bit like the individual three flashing blue light on the top of the dash, that clearly displays what level the car is at, when charging on a Nissan Leaf.
Off course, if we had the "App" we could check it on our phones !.
Hey - Let's not get started on THAT subject again please folks.
IF - The OP had a "Smart" meter, you can tell from this when the car has entered to "Balancing" process.
The smart meter will report only about 300 watts when it is coming to the end of the balance.
On a wall box, the ZS EV will pull about 7.2 kw's from a low SOC - right up to about 97% SOC.
It will reduce the demand down to about 3.5 kw's until it reaches 100% fully charged mark.
Then it will commence the balance cycle.
Depending on the level of imbalance in the pack, will depend on how long this takes.
 
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