Somewhat odd battery behavior

[sethr]

So, I'm perplexed by two things I've noticed more than once... One, on completing a standard charge, sometimes the ideal miles go up by a couple of miles, an hour or two after balancing was complete. Recalculating so late?

Secondly, although it balances to the cells being within .03 volts as it should after balancing, after a drive, sometimes even only 10 miles, the cells are within .01 - .02 volts. After charging it again balances to .03. Huh? Is it balancing as I drive?

I should mention that brick #91 has always been lowest, I assume because when I got it as a CPO, it had only been driven 1,000 miles in its first three years of life, and I'm supposing it got seriously out of balance being on storage mode a lot. Also, the last four months the CAC has been going down faster than before, from around 153.2 to 150.9. I only do a range charge about once a year, so maybe some inaccuracy there. I'm at 33K miles now.

I'll be very interested to hear any comments the community may have. Thanks!

 

[hcsharp]

The range will increase after a charge if the battery warms up. A lot of people notice this if they charge at night or first thing in the morning when the battery is cool. Then as the day warms up the range will increase by a mile or two.

Your CAC will make sudden calculation adjustments of about that amount (2 - 3 ah) if the car receives some information that helps it recalculate more accurately. The most common reason is a deeper charge cycle than it normally does. You probably took a longer drive than you normally do recently.

 

[Gizmo74]

I noticed similar on my roadster. If the battery goes slightly out of balance (0.04 or 0.05 V) then SOC shows a difference between 5% and 7% between MIN and MAX. So it stops on MAX 89% and MIN 82%. After some balancing, voltage difference goes down to normal 0.02 or 0.03V, but SOC still shows the big difference. After some hours it recalculates and jumps to about 84% MIN / 87% MAX, and standard range rises up this 2% (caluclated on MIN).