Author Topic: limit of battery charging time  (Read 753 times)

plukcc

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limit of battery charging time
« on: April 15, 2014, 06:46:46 AM »
How many times can our battery be charged ?
If I charge the battery when it is e.g. 90% to full charge
Will the battery life shorten 1 charge time that is same as I charge it at 10% to 100% ?

protomech

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Re: limit of battery charging time
« Reply #1 on: April 15, 2014, 07:25:33 AM »
Generally speaking, no. Frequent charging after shallow discharges is okay for lithium chemistries .. and in fact can be gentler for the battery than frequent deep discharges.

It's a simplification, but rated cycle life on the batteries is typically listed at some number of charge cycles to 80% original capacity. For the Empulse, this rating is 1500 100% cycles.

This means you could charge the bike 1500 times 0-100%, 3000 times 50-100% (or 25%-75%), or 15000 times 90-100%.

In practice, cell age, heating and storage SOC seem to degrade battery capacity more quickly than cycle count. The Phoenix Nisan LEAFs are a good example.
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Shinysideup

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Re: limit of battery charging time
« Reply #2 on: April 15, 2014, 01:08:34 PM »
It's my understanding (gleaned from this board) that OCCASIONAL deep discharge (say 10%) is good for the batteries and I try to make sure I do that once or twice a month.

What's the story on Phoenix Leafs? Batteries got cooked?

protomech

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Re: limit of battery charging time
« Reply #3 on: April 15, 2014, 02:49:45 PM »
Yes, basically.

A group of Nissan LEAF owners had their cars tested, results came back at 70-80% original capacity after a year or two, the worst of which was ~60% original capacity.

http://www.greencarreports.com/news/1079244_independent-tests-show-nissan-leaf-electric-cars-lost-range-in-hot-climates

Phoenix is somewhat atypical in that it is very hot for much of the year, frequently exceeding 100F or even 110F for months at a stretch.
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