That's just beyond the warranty period, like all of wally-marts
First check the voltage coming out of the alternator at a higher than
idle engine rpm.
It should be no more than 14.2 volts. If it is than that is the reason
the battery is failing.
Err ... Actually battery manufacturers recommendations are:
Lead-Acid Maximum charging voltage 2.45 - 2.7 VDC/Cell or
14.7 - 16.2 VDC/12 volt Battery
Gel-Cell Max Recommended voltage 2.35 - 2.4 or 14.1 - 14.4
AGM Max Recommended 2.35 - 2.45 of 14.1 - 14.2
My own experience is that few, if any, automobile systems will put out
a voltage high enough to be of danger to any of the three batteries
and that gel-cells, at least, can be a direct substitution for
lead-acid with no problems, and I certainly know people that installed
AGM batteries in their boats and didn't report any difficulties.
It is useful to note that the only advantage that Gel-Cell or AGM have
over lead-acid is that they don't spill if you turn them over.
Not the ONLY advantage. They also do not gas under normal charge or
In aircraft use a "wet" battery needs to be in an enclosed and vented
battery box, while AGM and Gel batteries can just be strapped down
Gel and AGM batteries are not considered hazardous cargo either (which
is mostly due to not being spillable) but there are valved spill-proof
wet batteries as well - which are NOT non -hazardous.
Not true today with maintenance free batteries. They are shipped wet.
VERY FEW lead acid batteries today are shipped dry - the exceprion
being motorcycle batteries and cheap utility batteries - the vast
majority (other than industrial deep cycle etc) are maintenance free
sealed or semi-sealed batteries.
I recently diagnosed the charging system on my car. The
manuals and such (I have a few) weren't much help
beyond what-wire-connects-where, but there were some
very odd indications.
You can charge a battery, give it a known discharge,
and see if it is holding enough energy. My battery was OK.
You can monitor the charge voltage to see if the normal
operation causes the correct charging voltages (in the
13 to 14.5 range). This, was inconsistent. Tightening
wires and replacing one cable seemed to fix it.
But almost nothing else; there was no easy way to
test the generator ex-situ, or any clear indications
what the voltage regulator was doing except as part
of the full assembly of components.
So, there was no clear determination of what to replace.
The generator came with a helpful little pamphlet that
said 'replace the voltage regulator at the same time',
and it's a common recommendation to replace the
battery after any charging problems. So, I'm thinking
a 'professional' would replace battery, regulator, generator
all at the same time. Whether they need it or not.
Without ever diagnosing to the individual faulty part.
That's just bad engineering.
My problem was an intermittent short inside the generator,
which clobbered the battery charge four times in
the space of a year (but usually worked when the
meter was attached).
Sounds like your regulator points are sticking or welding shut once in a
while draining the battery back through the generator. The contacts
on the regulator close when the output of the generator reaches about 12
volts, below that they should be open. You could put a heavy current
diode in series with the generator to prevent this back current flow.
New technology combined with old. :)
Is this vehicle older than 1963? Hasn't been a DC generator with a
cutout relay installed on anything (except perhaps in Russia or
elsewhere in eastern Europe) since that time.
More likely an intermittently shorted diode.
Intermittents are difficult to troubleshoot, but back in the day I was
pretty good at it (and still surprise myself every once in a while
when I get called in on a "stickler")
He did say he had a generator which almost never came with a solid state
regulator. I installed a bunch of the Motorola alternator kits when I
was a kid working in the local garage, as well as overhauling generators
and starters. The sticky points on the regulator was usually the
problem with intermittent dead batterys.
Hey, I did a lot of "generator" work in years past , and saw the
sticky points etc too - but my bet is he said "generator" meaning
And most vehicles in the last 30 years don't even have external
regulators any more. The ones that do, they are built into the main
An alternator is a type of generator. Even the service manual for my
2009 truck refers to the "Generator", which is clearly a three phase
"The PCM simultaneously controls and monitors the output of the
generator. When the current consumption is high or the battery is
discharged, the PCM will raise engine speed as needed to increase
generator output. The generator charges the battery and at the same time
supplies power for all of the electrical loads that are required. "
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