Sprinty said:Also what do you mean 1 of the 1000 cycles?
MikeS said:Handbook p52 states - charge when below 30km otherwise performance of the electric drive will appreciably deteriorate.
agj said:Sprinty said:Also what do you mean 1 of the 1000 cycles?
I am not a specialist, but "cycle" means "complete charging". Any battery has a life span of X "cycles" before it starts to deteriorate. Just like any camera has a number of shutter releases before it needs servicing.
A short charging is not computed as a "cycle" but as a "partial cycle" and does not account for the 1000 complete cycles. Hope that was clear :shock:
Maybe someone who REALLY knows can confirm.
ultraturtle said:There is no carved in stone "1,000" cycle limit on the life of a lithium ion battery pack. There is, however, a relationship between depth of discharge (DOD) and charging cycles
I think it was General MacArthur who once said "an old lithium ion battery never dies, it just fades away" There is a growing industry repurposing EV battery packs for stationary power backup and load leveling applications after their capacity has dropped to a level that is no longer practical for motive energy.Alessandro said:Just curious, but what about after those x cycles of charging ? I mean, is there a linear degradation or a more drastic, i.e. exponential loss ?
As it ages, the battery pack will maintain roughly the same charging efficiency (ratio of kWh out to kWh in). Only the total kWh capacity drops.Alessandro said:And on the charging side, will it take more kWh to charge it with aging ?
I don’t know enough about these batteries to make a specific statement myself. However, I do not consider BMW’s advice in the handbook can be misinterpreted - it states ‘Charge the high-voltage battery when the range is below 30km, otherwise, the performance of the electric drive will appreciable (sic) deteriorate’.ultraturtle said:BMW's guidance to "charge when below 30km otherwise performance of the electric drive will appreciably deteriorate" may be interpreted incorrectly, causing some confusion. The life of a lithium ion battery pack drops drastically when repeatedly discharged deeply. In my opinion, they do not mean to encourage the owner to discharge below 30km range remaining, but are advising them against doing so unnecessarily.
fdl1409 said:This advice does not refer to the battery life span, but to the power is can deliver. Below 30% SOC, the voltage is low and the performance of the car reduced.
Yes, I suspect that is the correct interpretation. The manual provided is poorly presented and poorly translated - the statement being discussed is in the manual under the CHARGING VEHICLE/RANGE section.
I wonder if someone who has a hard copy of the english version of the manual can say what p152 says in this section? Or have they left in the typos and mistakes?
ultraturtle said:There is a growing industry repurposing EV battery packs for stationary power backup and load leveling applications after their capacity has dropped to a level that is no longer practical for motive energy.
Alessandro said:And on the charging side, will it take more kWh to charge it with aging ?
As it ages, the battery pack will maintain roughly the same charging efficiency (ratio of kWh out to kWh in). Only the total kWh capacity drops.
SanSerif said:The entire manual is grammatically and linguistically challenging. It's a rather poor translation and I would take any statement as gospel!
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