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battery death is most often a case of murder 3 Saabers Like This Post!
Posted by bobc [Email] (#473) [Profile/Gallery] (more from bobc) on Mon, 24 Feb 2020 13:25:18
In Reply to: Hmm...could alternator have killed this Bosch early?, NCCaniac [Profile/Gallery] , Mon, 24 Feb 2020 09:50:20 Members do not see ads below this line. - Help Keep This Site Online - Signup
TLDR: Yes your alternator could certainly be guilty of murdering your battery. more on that below.
Side note, I traditionally hated Walmart batteries, for a time they were bonafide crap. But in the last 5 years or so I've come around. But they are now made by Johnson controls and are decent batteries and have an excellent warranty.
I believe that Optima batteries are also made by Johnson controls.
I believe that Bosh batteries are made by Exide
(there are rather few actual manufacturers of battery lead acid batteries)
- catastrophic death: A battery can die from plate failure. This is sudden and rare. the mounting structure fails and one plate touches, shorts out against, an adjacent plate. You may have experienced this: a dead battery but a jump start has no effect. in order to start the car you have to take the failed batt out of the current path, usually just disconnect the neg and clip the jumper cable to the neg cable directly.
- murder by neglect: (neglected by the charge source, not neglected by the owner). This is a slow death. if the charge current is too small, either due to a failing alternator, a failed regulator that over-regulating, or high resistance in the wiring between the batt and the alternator, the battery will charge very slowly and spend too much time in a discharged state. On short trip will will not even recover the charge that was lost from starting and running.
With any lead acid battery, the more time it spends discharged, the more sulfation will act on the lead plates. This will slowly suffocate the battery, until it can no longer start the car.
- boiled to death: if the charge current is too high, the reaction at the plates will be be too fast and the electrolyte will boil off. you can hear it happening. there is a nasty side effect of the release of explosive hydrogen gas. This is usually the cause of a failed regulator that is under-regulating (and allowing a very high voltage to pass to the batteries)
- old age: batteries can simply die of old age. this is what we hope for in our batteries ... to live a good life, and die with dignity.
I'd say that Murder by neglect is the most common scenario for our cars. A fairly high "always on" drain combined with less than stellar charge wiring means that our alternator and regulator need to be at 100%. Once they start to degrade, the car starts to face a charge deficit leading to premature sulfation and inevitable suffocation and death.
side note: the regulator is built into the alternator and not replaceable. but I have occasionally toyed with the idea of installing an external, high end, voltage regulator. It would be an interesting experiment ... if it weren't for the constraints of time and money.
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