Quote:
Originally Posted by rxtian
I just did the same on my 2015 D4.
I considered just doing the battery reset without changing the battery, but since it always turned off start stop not long after a charge (even if that charge was 5+ days at a fixed voltage from a 60A supply during lockdown), I figured the BMS was correctly able to identify the battery weakening after a charge.
So far the new (large/main/cranking) battery has stop-start going within about 200m of a cold start, and its been working all week without any external charging.
I expect the original battery would have soldiered on for years without stop start, but it's nice to have full functionality and no scary "low battery" warnings.
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I tried resetting the battery monitoring system about a year ago, so I know it wasn't simply that.
I'd also tried to 'revive' my battery as above on an old trickle charger, plus using the 'recover' mode on my smart charger to no obvious benefit. My Hyundai smart charger gives an approximate charge % whilst charging and - worryingly - would usually show that there was only 10-20% of charge remaining in my old battery whenever I began charging (something I was in the habit of doing at least once a month)... while such a low charge is fine for starting in normal conditions, I was becoming concerned that sub-zero temperatures would be a double whammy for the aging battery in that the residual charge would fall even lower at a time when greater cranking current and duration was demanded, plus of course following a potentially lengthy glow plug load.
I agree with you that my original battery may well have kept going through the winter and beyond but I saw no advantage in waiting even longer to replace it. I'm only going to replace it once and so why not sooner rather than later!
It seems to me that Volvo have designed the battery monitoring system to expect the performance of a near-new battery. I never get similar warning messages and inhibited stop/start performance with my diesel Sportage, so I guess that must be more tolerant of the aging battery? It is 2 years younger than my Volvo but by this age the Volvo was already being a nuisance in this regard. It is a relief to have replaced the battery and gone back to having both cars acting normally and not needng to regularly having to nurse either with a smart charger...