Sudden range nose-dive: Advice?

[mongo]

I see a few options
1. The battery balancing circuit had a brain fart and drained #4. Once it is balanced, you'll be fine.

2. A cell in #4 failed open. Once the pack balances at the high SOC, things will look good, but total pack capacity will be reduced and when used, #4 will hit the voltage floor first. However, the pack will charge back up to the high SOC.

3. There is a resistive fault in #4. Any time spent off the charger will result in increased imbalance.

 

[CruzInVA]

UPDATE!!

Wow..what a difference!

Per the attached screenshots (now labeled with dates for easy of decypherment), my weak brick (#4) has improved from 3.97v to 4.04v between July 17 and August 2. The strong brick (#27) has remained steady at 4.08v.

Meanwhile, the SOC MIN/MAX split has gone from 75/88 to 85/88.

This morning (August 2) it showed post charge Ideal Range at 174, which I believe is about where it should be for the indicated CAC of 144.59Ah. Correct me if my math is off on that one, please.

You recall I was getting ranges as low as 148 in mid July.

I will monitor the numbers regularly now that I know how, to see if it stabilizes.

One remaining question i have is whether the CAC itself is accurate. Seems about right for my mileage, based upon the old survey data averages. I did read in one of the other threads that there is a theory out there that the CAC could be off if the battery had not been run down to a low level in a while. The idea being, it seems, that the computer may not really know where the bottom of the available charge actually is, and thus its estimate of the CAC (that being the ‘Calcualted’ part) may be thrown off a bit.

I do know that my car has not been driven down to anything close to empty in quite some time.

Is it worth doing and extended drive to push it down below around 20%, then a full recharge just to see how it effects the numbers?

You guys are the best, btw!

Thanks for all the help!

 

[PowerSource]

Nice gains, your issue could stem from putting it in storage mode that often. Many times that can create issues with the balancing. Personally, wouldn't use storage mode unless you plan on not driving it for 2 weeks or more.

 

[markwj]

Zombie roadster - back from the dead. Congrats. So, this was a balancing issue?