I have an portable emergency battery (or whatever it is called),
a nice unit by Schumacher which goes by the name Instant Power.
Their documentation describes it as providing an emergency power
source, and I've used it for a number of such (though non-emergency)
purposes over the past few years. Recently I have noticed two
curious things about it.
First, when I try to use it to start the Spitfire which I know to
have a weak battery, the car's starter doesn't always respond as
if a new battery was attached. In the past the Instant Power always
made a big difference. I have checked and cleaned the car's wiring,
ground strap, etc. so I don't think that is the reason for the
apparent fall-off in performance.
Second, when I hook up the 120volt input to recharge the Instant
Power, the green "Fully Charged" LED turns on after a very short time.
Okay, I haven't actually timed it but it sure seems faster.
It appears that the car simply isn't drawing much current from the
Instant Power, perhaps none, to judge from the starter's behavior.
The problem could be still in the car, a poor connection in the
solenoid or a weak motor. But I'm wondering if the Instant Power
unit might be aging. If it were dying the way a car battery dies
eventually, could this produce the behavior of seeming to recharge
very quickly? Possibly because high resistance make the charging
system think it is fully charged? Would the three status LEDs be
a good indicator of failure, or merely indicate the charge state
of the battery unit when it is good?
I sent a query like this to Schumacher and received the ambiguous
and unhelpful answer:
> I would suggest that it very well could be the battery breaking
> down, and needing replacement.
Uh, which battery? The one in the Instant Power or in the car? I was
actually asking about failure modes. I'll replace the Instant Power
if necessary. Or the starter and/or solenoid. The motor has always
been weak turning over the engine against the compression when the
engine was hot, and lately it has begun making unhappy spinning
noises when releasing after the engine starts.
Jim Muller, looking to avoid unnecessary spending
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