Charging after Reinitizalization of Battery Pack

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symonray

Well-known member
Joined
Mar 7, 2019
Messages
79
I own a 2016 i3 Rex. A couple of months ago, I used the ISTA software to perform a reinit of my battery pack. Everything went smoothly, and the results have been very beneficial. However, ever since completing the battery pack reinit, I have noticed that the charging stats generated by my Juicebox 40 Pro charger are reflecting a higher amount of electricity being added to my battery pack to reach a full charge than before the reinit was performed. For example, on those rare occasions when I have charged the battery from around 5%-10% to 100% (I normally keep the battery in the 25% to 85% range), my Juicebox is now showing 20.5kwh to 21.5kwh being added to the battery. Is that the result of the battery reset freeing up additional usable battery capacity in the battery pack? I know the total battery pack capacity is 22 kwh (around 21.6 actual) and that the BMS supposedly maintains a high and low non-usable buffer to keep the battery healthy. Thanks for any comments.
 
You could easily check cell voltages at 100% and close to depletion using ISTA+, as well as reported cap and floor buffers. Check my post here for more details https://www.mybmwi3.com/forum/viewtopic.php?f=11&t=13535&p=56484#p56484.

As far as the electricity getting into the pack is concerned, I have daily stats on lots of stuff re my i3, and this one is the least reliable with significant daily variability. I monitor the kWh used for charging the pack vs. the previous day remaining SOC in kWh (via Batt.Ladung in hidden menu). The resulting losses during charging range from 0% to 35% in the most extreme cases, but usually flock in the area of 6-15%.
 
During charging, some of the power is lost in the conversion process (maybe in the order of 6% on 240vac, more on 120vac), some is potentially used for cooling (more so the deeper the discharge), and if you precondition, some would be going towards that. In the summertime, you probably won't need to warm the batteries, but the cabin conditioning can take a bit especially if it is sitting and soaking in a hot sun.
 
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