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Old 07-01-2020, 01:11 PM   #6 (permalink)
PowerSource
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Quote:
Originally Posted by B. Surm View Post
How long does the balancing take?

I drive and charge my car very regularly and had no issues with the battery yet. But now my contactors are changed I try to use them less by unplugging the car when it has reached a full charged, because I have heard them clicking some time during the day when plugged in and being full charged for some time at that time. I am on 525, because 535 makes more use of the contactors right?



I believe there was 520 and 530/535


Both 530 and 535 were disasters... 530 inadvertently removed battery balancing 535 added it back in. Both actuate the contactors to charge the 12v battery via APM. It is a very slop-shoddy algorithm in that it will wear out the contactors in a couple years- to save a 200 dollar 12v, relatively easily accessible, battery- which can be maintained via a 20 dollar tender or by parking the car outside.


Also looking at the spec for the contactors in the EDM

located here on page 2

http://www.te.com/commerce/DocumentD...ntxt=1618002-7


It looks like the contactors are rated for 1-10,000 cycles at 400V dc

So say the contactors close for the battery tender feature once every hour that is 8760 times in a year (not taking into consideration turning off/on the car etc). Pretty close to the life-cycle spec of that particular contactor. I am not sure how often it checks the 12v battery.




Yea, if you are on 535 would recommend downgrading to 520, before you have to drop your pack and replace contactors.


If you do not charge the battery for weeks at a time, it is possible the cells deviation will be out of balance and the resistive BMS will not be able to bring it within spec- which means the pack has to be dropped again. Would recommend charging at least once a week. Once the pack goes out of balance you will have far more issues. In order to meet the contactor life specification of 10,000 cycles (assuming not a weld failure) that is 27 years if you charge once every day. 10,000/365= 27.3 years. There is no danger in charging every day.
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