Well my tester also measures charging voltage and it seemed ok...
Interestingly, I took one of the cars into Advanced Auto Parts today and
they had some "fancy" (proprietary they claimed) computerized battery
tester that supposedly does all types of things that a standard 100A
load doesn't test. And that battery tested just fine - it measured a
voltage of 12.79v and a CCA of 574 (vs. rated 582). I was surprised
because I was almost sure that they would have "rigged" the test to sell
more batteries so that just about any 4 year old battery would test
bad. But the guy was nice, helpful, and surprisingly honest....
While the screen and printout were pretty cool, not sure I believe it
does all that more. Also, not clear to me how you can measure CCA at all
accurately when the ambient temperature is not 0F but I assume it does
some type of temperature adjustment since the screen and printout had a
temperature measurement on it (though since it said 73F, it seemed like
maybe it was the room temperature of 73F where the machine was stored
and not the outside temperature which was in the low 40s - though maybe
there was a temperature probe in the battery connection and that was the
under the hood temperature).
But in any case, if the store selling batteries tells me my battery is
good, it seems like it probably is.
Yes, if there's enough I believe it conducts electricity and will
slowly drain your battery. Or maybe even quickly at some point.
I pour 5 or 10 heaping tablespoon's worth, I'm guessing, of baking
soda from the box on to the top of the battery and then pour water,
usually warm water from a tea-kettle, on top of that, slowly to not
wash it off before it neutralizes the acid. When it stops bubbling,
it's done, and I wash the rest off with the rest of the tea-kettle.
HR Bob's is the correct method but you asked for easiest/fastest, and
as far as I know, mine works just as well. Maybe the other method is
meant for shops which will keep a bottle of solution around to do more
than one car.
That is a good first step, if you have baking soda around, and reduces
the chances of trashing your favorite shirt. But you STILL need to take
the connections loose and clean the terminals. And one step I forgot in
previous post- lots of fancy stereos don't just lose the station
settings when battery is removed- they lock themselves down in
anti-theft mode, and can only be unlocked with the special code. Check
your owner's manual to be sure. If you don't have the magic number,
they sell a 9v battery thing that plugs into cigarette lighter to keep
the radio alive.
Oh yeah, I forgot to say something about that. Probably because I
haven't needed to do that for a long time. I think those red and
green felt washers must be responsible. I haven't had much in the way
of dirty batteries since I started using those.
But the OP can get a good terminal brush at an autoparts store, with
one brush to clean inside the terminal and another brush to clean the
outside of the post, all in one convenient tool.
Very good idea. My friend got the code from the dealer, even though
she bought her car used from somewhere else.
True. without that specific tool, as a young man a pocket knife worked
nicely. I've cleaned many battery terminals and cable connections with
just a pocket knife. Cranked the truck and left the swamp - more than
The OP should " clean car battery terminals " <G>
Nothing wrong with new tools!
- What are those "red and green felt washers"?
- Are they some after-market product that I can buy?
- Also, what causes this accumulation of gunk?
- Where does the "gunk" come from?
- Does it mean the battery is leaking?
- Does it cause permanent damage to the battery?
- Does it mean the battery is nearing the end of its lifespan?
- Other than "red and green felt washers" is there anything I can do to
prevent such build-up in the future?
Thanks for ALL the helpful replies...
I don't know that the washers really work... I have a non-sealed
battery in my pickup truck and it still gets a little cruddy.
I'd recommend using Vaseline or Sil-glyde on the terminals and also
put a "battery mat" underneath the battery to keep from rusting the
tray out. Just this past weekend I removed the battery tray in the
pickemup to assess what hardware was corroded, and I've ordered
replacement hardware, some POR-15 to paint the tray, and a couple
battery mats so I can put one in each vehicle.
I'd also recommend slathering the clamp bolts with anti-seize so the
nuts don't seize up on them. It'd be nice to find some stainless
battery bolts but I forgot to check to see if McMaster-Carr had them
in stainless the last time I ordered.
Yes, they used to be a dollar a pair. Maybe a little more now. I'm
sure they have them at "real" autoparts stores but they have them on
display usually at consumer autoparts stores like Pepboys.
I know some people don't think they work, but my personal impression
is that they work great. There have been some battery changes that
might possibly have made battery problems get less frequent but I'm
pretty sure I bougth the washers when I didn't change my battery and
there was a big improvement with the same battery. Put the red on
positive and the green on negative. I use the same washers for
years. It *is* a little hard to believe they don't wear out, use up
their chemicals, but who knows. All I know is I don't have gunk
problems anymore, and only use baking soda once every year or two or
The liquid in the battery is sulfuric acid with a little lead
dissolved in it. The gunk is some sort of sulfate, with maybe, I
don't know for sure, some lead sulfate. That's why it's yellow, from
No. It does mean some acid got out, but that's not the same thing.
No. There's loads of acid still left inside. It doesnt' take much
acid to make that crud.
No. It's not like a flashlight battery's leaking.
About 20 or 30 years ago they came out with No-maintenance batteries,
which couldn't be opened to add water, and which also I think meant
that the acid coudn't get out. I lost track of whether these things
were as good as they said. Ialso lost track of whether there was
some small vent for each of the 6 cells in a 12 volt battery. I think
there was. I think they used a slightly different acid or plate
A couple years after that, they came out with Lo-maintenance
batteries, that looked like No-maintenance, in that there seemed to be
no caps for the cells, that the battery coudln't be opened to add
water. But they had just redesigned the caps, put 3 caps together
(and used two of them, for a total of 6 caps) with a very low profile
and no apparent place to lift, so they looked like No-maintence, and I
think the chemistry was slightly different so it was not necessary to
add distilled water as often as it used to be. And maybe voltage
regulation of the charging system had gotten better, because charging
with too high a voltage causes water to evaporate from the electroyte,
which is water and acid. Anyhow, it's true, I think, that one
doesn't have to add water to batteries nearly as often as one used to.
I'm not the best example of maintenance, but I only check the battery
ever couple years. I never needs much water, if any.
Be sure to tighten the terminals tight enough, but not too tight!! :)
I haven't looked for stainless steel bolts, and I did once in 45 years
have the bolt rust through, largely because of the battery acid, but
they sell replacement terminal bolts, and it was easy to replace it.
But once or more I havent' tightened the bolt enough. When it is at
all loose, that makes it more likely the crud on the outside will get
up between the post and the terminal. When it's properly tight, it
either doesn't or it takes longer, not positive. So one time, I'm
driving and the car stalled and I was taking a friend to catch a train
so I didn't want to waste time. I touched both terminals and one was
hot. That's because it was loose. I just turned it left and right as
much as it went and then tightened the bolt and the car was fine after
that. It wasn't actually that loose, and there was none of the
visible crud, but maybe there was something else.
BTW, I keep an open box of baking soda in the fridge, to reduce odors,
but the fridge had a label that it had a special finish that woudln't
retain odors. I don't know if is special or not. It's a whirlpool
fridge. Nonetheless, I keep it there. For one reason or another, I
don't smell odors.
I've been using the same box for 27 years :) and the only time the
amount in the box decreases is when I clean the battery, which has
only been about 10 or 15 times in the last 27 years.
Some people use baking soda for baking.
I clean it in place too. It's fine that way. Someone called
attention to your subject line. I pay little or no attention to those
and only look in the body of a post, but you did emphasize terminal in
your first post too, yet I concentrated on crud.
If there is crud right on the terminal, right next to the where it
touches the post, it might be under the terminal too. It's probably a
good idea to remove the cables and clean the posts and inside the
Remove the ground first. The one with a - symbol on the battery (not
a + ). Now the symbols can be hard to see, and in all recent cars the
plus terminal is the one whose cable goes to the starter motor or a
solenoid. The negative terminal goes to a bolt on the engine. It's
the negative, the ground, you want to remove first. This seemed
counter-intuitive to me, but if your wrench touches the body of the
car while you're working on the negative, nothing will happen. Then
after the neg is disconnected and you are using your wrench on the
positive, and your wrench touches the body of the car, nothing will
happen. If OTOH, the negative was still connected, there would be a
big hot spark, enough to melt metal, at least a small amount. So
disconnect the ground, the negative, first. If you're not sure,
there might be a label somewhere, or someone with a meter or who knows
cars can tell you which is the negative.
If that doesn't work, clean the battery once without disconnecting it
and then maybe you'll be able to see the + and - symbols, although
they can be on the side where it's hard to get a good look, or
obscured by the terminals.
Take a flashlight and look down alongside the battery, and see if the
tray is painted metal or plastic covered. If painted metal, and you see
rust when you peek down there, good idea to pull the battery and repair
as needed. (paint, reinforcement, etc.) It can ruin your whole day if
you are driving down a bumpy road, and the rusty hold-down bolt breaks,
and the battery bounces and shorts out against the inside of the hood. BTDT.
Yes, I grew up driving junk. (Why do you ask?) But on a young car,
cleaning in place is usually fine.
Magic smoke, and car no worky. (Magic smoke is what makes all electrical
devices work- you let out the smoke, and the device doesn't work any
more.) Dead short across the battery fried the fusible link in the feed
cable, like it is supposed to. A little blacksmithing on battery tray, a
new hold-down clamp (the old tall kind, not the modern low clips) from
the junkyard, a new fusible link segment and some compression
connectors, and it all came back to life. This was a
pre-electronic-everything car, mind you. Hate to think what it would do
to a modern rolling computer.
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