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KendallP's avatar
KendallP
Explorer
Oct 18, 2013

A Question About Gravity... Specifically

Hey guys,

So as I do every year going into winter, I tested, equalized and retested my sedan's starting battery. (Don't tell MEX that I drove with cloudy electrolyte yesterday after the equalization. I should have done it in the evening when it could rest overnight.)

After a charge and equalization with the Vector, I hammered the battery with the Harbor Freight beast with about 16.85V for 1 hour and 45 minutes. I'm pretty confident that I couldn't have done much more.

My efforts appear to have netted me about a 0.010 or ~6% gain Not stellar, but better than a poke in the eye with a sharp stick.

So adjusted for Temperature, my readings are...

1. 1.253
2. 1.263
3. 1.263
4. 1.263
5. 1.263
6. 1.243

Not terrible for a 5 year old starting battery in a car that makes a lot of 10 minute, short hauls to work and back, but I think it fair to say she's entering her golden years.

In 35 deg. F conditions, it pretty well fires the 3 liter V6 right up. Before the equalization, though, I did notice a little sluggishness in the morning starts which reminded me that it was time to equalize. It seems that a 6% gain made a subjectively measurable difference.

My question is this...

According to my best chart, 1.243 is about 87%, where 1.263 is nearly 100%. Of course this is ASSuming that the SG when new was also 1.263 or so. I don't recall what it was on this particular battery. I think I may have neglected to take an initial reading on this one.

Now if we average the cells, we get 1.258 for about 93%.

Some folks say that a battery is only as strong as it's weakest cell. Is that really true or do I have more like a 93% battery here?

It is what it is and it'll do what it'll do, but I'm just curious.
  • MEXICOWANDERER wrote:
    Ever see an 80-year old clutch their chest?

    If it were mine señor, the very next time you even think I would notice a sneeze of difference in cranking, I would be on my way to get another battery.

    Many newer cars today use gear reduction starters that demand less than half the cranking amperage of the old fashioned direct drive starters.

    Call it a gut-feeling KendallP but The End Is Near. Repent.

    Forgive me Father MEX, for I have sinned! How many Rosaries are we talkin' here, Father... to get me right with the battery gods?

    OK, I'm sure you're right. If it were my wife's rig, I would definitely pay serious heed. That's the rig we take to the snow and the one that she makes regular trips to Santa Cruz in with our little girls.

    My rig rarely goes anywhere too cold or too far away from home base. But I'll pay close attention to that starter... if anything just so I don't stress it and force an unplanned trip to the shop.

    Now...

    What's your opinion on the weakest cell in the chain question?
  • Thanks for reminding me to do an equalization on the fleet before Winter arrives in earnest.
    I'm of the old school, Drive-it-until-it-won't deliver College. I'm nursing an 11 yr. old Motorcraft in my truck, presently. I can see that Hospice is not too far off.
  • Ever see an 80-year old clutch their chest?

    If it were mine señor, the very next time you even think I would notice a sneeze of difference in cranking, I would be on my way to get another battery.

    Many newer cars today use gear reduction starters that demand less than half the cranking amperage of the old fashioned direct drive starters.

    Call it a gut-feeling KendallP but The End Is Near. Repent.

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