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So I've been wondering - if it takes longer to charge the last 20% of the battery's capacity, is it also using more electricity to charge that 80-100% than to charge from say 40-60%? Meaning, is it less efficient, as well as slower? Seems it would be, but I only see it mentioned as a time issue, not an efficiency issue. Thx.
 

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Li-ion use a combination of CC + CV..
Constant amperage is maintained until 4.05V and then it switched to constant constant Voltage.

The max V for Li-ion is 4.20V but leaf send to be charging up 4.11V

20-80% CC
80-100% CV

Charging is normally terminated when amps going in drop to sub 100mA
 

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That's fantastic. Whatever it means! Is there a dumbed-down version? As in, would you be charged the same amount to charge your car from 80-100% as 40-60%? Another way pf putting it, is there a financial incentive to not charging (for example) over 80%?
 

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That's fantastic. Whatever it means! Is there a dumbed-down version? As in, would you be charged the same amount to charge your car from 80-100% as 40-60%? Another way pf putting it, is there a financial incentive to not charging (for example) over 80%?
The charging is slower.. heat losses higher.
Not much in terms of financial incentives.. though battery degradation is higher.

For longest battery life. In terms of cycles, 3.93V is considered the best but charging to 4V is considered decent enough..
100% DoD 400 cycles.

Every 0.1V drop in max V doubles numberOf usable cycles

4.20V: 400 cycles
4.10V: 800 cycles
4.00V: 1600 cycles
3.93V: 2000 cycles
 

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You pay for electricity in kWh. The initial charge rate will be high on a rapid for example the 20%-80% could require 18KWh on a 30kWh leaf and be delivered in 30 mins, the 80% to 100% may be 6kWh but delivered over 30 or so minutes as well. Whilst the charging speed decreases the cost per unit charge (kWh) remains constant.
The chargers are slightly less efficent at slow rates, charging losses are higher, but this is minor in terms of the power used and is in the order of coppers.

Think of it as water, you pay by the litre it doesn't matter if the tap dribbles or is full on.

Note I do not have a leaf and the examples are idealised but it should give an idea.
 

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Discussion Starter #6
Thx folks. That makes sense. I just wasn't clear on if the flow of electricity decreased along with the slowing charge rate, or if it just got less efficient.
 

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Note, those voltage/cycle combinations should not be interpreted as being strictly applicable to the batteries fitted to any modern BEV (possibly something like a laptop maybe)
 

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The best analogy I have seen is filling up seats in a cinema with unallocated seating.
To start off with, it's easy for the people to find a seat and they can get sat down pretty quickly.
When the cinema fills up, it takes longer for the customers to find a free seat.
Eventually the box office will have counted that there's nobody able to find a seat, or that all the tickets have been sold, and still stop selling tickets.
The price of the tickets is constant, but there may be some losses and confusion as people want to sit together and can't find a seat, arguments occur, get hot and bothered, and the box office refuses a refund.
 

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Note, those voltage/cycle combinations should not be interpreted as being strictly applicable to the batteries fitted to any modern BEV (possibly something like a laptop maybe)
A Li-ion battery and is charge discharge doesntd change with application. Li-ion Batteries 18650, Prismatic and Pouch have been used in laptops, medical equipment and cars.

Nissan leaf uses 2P2S pouch module based cell.

BTW I tested Nissan Leaf with 80% charge and the batteries still reported at 4.11V.

Might try 70% next.. trying to identify the usable voltage range.

LTO is a new kid on the block however in not sure which manufacturer uses them.
 

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So I've been wondering - if it takes longer to charge the last 20% of the battery's capacity, is it also using more electricity to charge that 80-100% than to charge from say 40-60%? Meaning, is it less efficient, as well as slower? Seems it would be, but I only see it mentioned as a time issue, not an efficiency issue. Thx.
The charging input reduces towards the end of the cycle to protect the battery. Next time you at a rapid watch the amps / KW being delivered.

Sent from my SM-G930F using Tapatalk
 
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