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Battery Life AFTER car is on trickle charger

4K views 6 replies 7 participants last post by  fastfwd 
#1 ·
Ok guys, hope this isn't redundant.

The last time I drove my 12c was New Years Day, 50 degrees in Chicago believe it or not. At that time, the battery showed 99% without having been on the charger for weeks. I knew it might not see the the road for a while so I put the trickle charger on it when I got home. Took it out today, and as I pulled out of the garage, the battery was at 52%! AFTER 3 weeks on the charger! Drove the car for an hour or so, and the battery never went above 52%. in fact, it went down to 51% at one point. It usually steadily goes upon after driving for a while, regardless of what it was when first driving off.

Oddly though, the numerical % did not match up with the graph, which was very close to ful.l

Anybody had similar experiences?

Car is a 2012 that had 2,500 miles on it when I bought it, it now has 7,500 miles on it and never sits for more than a few weeks without getting exercised. Obviously driven mostly in spring, summer and fall in this clime.
 
#3 ·
I have the same issue OP...I noticed that once the battery reaches around the half life it takes longer for the battery to recharge compared to if it was at least 75%. Now, I constantly unplug the charger every few days so the trickle will have to recalibrate and start the charging process over again bc the car doesn't seem to fully charge when left unattended for too long. I'm not sure if it's a safety feature in the trickle so it doesn't draw too much electricity for a long period of time?
 
#5 ·
just drive the auto regularly for a while and watch the battery hit 99%, it is magic, smile. these autos like to be driven and they reward us when we do, maybe they are like children and get mad at us if we do not driven them regularly, but I think this goes for many auto, especially exotics.
 
#7 ·
Marketing documents from A123 Systems say 4.5x as long as lead-acid.

But the documents also say that the price difference between A123's lithium-ion starter battery and an AGM lead-acid battery is only $300, so it's possible that their longevity numbers aren't right, either.
 
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