20 HP B&S engine, 42" deck, 12V Exide Battery abt 1 1/2 years old. I
thought about taking this to a battery forum/group but IME you get a lot
better reality check here.
I accidentally left my lawn tractor key in the ON position and then got
sick so it sat that way for almost three weeks. The battery of course
went stone-cold dead over that time as it was also sitting out in the
sun on top of the key not being turned off. No, lights were not turned
on; key was just in the RUN position, not RUN/LIGHTS.
I tossed an 8A battery charger on it and it drew no current. No
spark, nothing as if the battery were an open ckt. Shorting the clamps
caused sparks and a current meter jump so power was on and the charger
was working. I gave it a few minutes and noticed it was starting to
take a charge; for an hour or so it sat around one amp. I cycled the
charger on and off a few times, turned the key and let the starter whirr
(wouldn't engage of course), and the charge rate moved up to around 3
amps and stayed there. It was mid afternoon by then.
Around 5 it was still charging at 3 amps so I took the charger off
and tried to start it. It's a good starting tractor so it started on
the first spark; the starter didn't even run enough to know whether it
sounded like the battery was almost up or nearly down. The charge rate
then was still around 3 amps by then, so I figured the battery was still
pretty low. I let it sit there for a half hour running, figuring I'd
charge the battery.
It sat at about 6A charging when I started the tractor and the
battery was being charged from the tractor's charging cktry. But about
a half hour later I went back to check, and it was showing a 15 Amp
So, I took it out and mowed in the big side field for awhile,
figuring that would let the battery charge and the bouncing around might
help any deposits in the battery drop off, etc.. But the meter was at
15A and stayed there throughout. Sound-wise, the battery seems fully
charged when the starter starts it even when it's nearly cold.
I haven't let it set over a couple days yet though, because this only
happened yesterday, but I plan to, to see if the battery is a battery or
a capacitor<g>. Capacitors self-discharge.
Nothing wrong with the meter: idle drops current to low value, 1/3
speed or more puts it up to the 15A. Charger OK, worked fine on the
generator battery to top it off. That only leaves the battery itself
and/or the charging cktry in the tractor.
Since 18A is 100% of meter deflection (an actual meter, not just a
coil of wire looped around studs), I'm assuming the charging rate might
actually go higher if it were possible to draw more current from the
charging ckt on the tractor. In other words, it's maxxed out. I did see
it approach 17A for a short time out in the field, but it quickly
settled back to 15A again.
NO change after mowing for a whole hour! Still at 15 Amps. Engine
was hot, but it started like ASAP and as though the battery were brand
new! I haven't had a chance to let it sit for a couple days to see if
the battery loses its charge quickly.
I forgot to mention: It's a standard lead-acid battery, a little
larger that normally found in lawn tractors because it's a 2-cylinder 20
HP B&S engine. IIRC the CCA (Cold Cranking Amps) on it was something
like 120 Amps and it had a 5 year warranty for what that's worth<g> and
the brand is Exide.
What really bugs me is, I just replaced the battery in the spring a
year ago! And I've probably ruined it now.
If I can't get my volt-meter back quickly I'll go to RS and buy a
cheapie for use here. As long as it'll handle over ten amps AC and DC I
should be able to use it to TS this.
Is it likely the battery is shot and can't be recovered?
I wasn't thinking quickly enough to check to see if the battery had
reversed its voltage; it was probably past even that point though, IMO.
Is it likely the charging cktry (just recifiers, but 4 of them instead
of the usual 2) was damaged and could be the reason for the permanently
high charging rate?
Any reasonable way to explain the apparently permanent high rate of
It's not logical to me that the charge rate would increase with
time like that.
Thanks for any relevent, knowledgeable feedback,