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Hydrometer readings - what to do?
By zmoz, Section Storage Posted on Sat Mar 05, 2005 at 02:31:29 AM MST
Is this bad?

I have a car battery that's been sitting out in the rain for about 6 months. The sticker on the side says it was made Dec. '03 and it hasn't been used once. I plan on using it soon for my boat, so I brought it in to charge it up.
I went and bought a $2 hydrometer to test it. 5 of the cells float 4 of 5 balls, which is supposed to mean a full charge. It hasn't been charged in at least 6 months, and it measures 12.54v. How could it possibly have a full charge?
One of the cells only floats 3 of 5 balls, indicating 3/4 charge. This cell also has more water in it than the others, looks like maybe some rain water dripped in. Is this bad? Can I equalize it by charging? Should I remove some of the acid to bring it to the level of the other 5 cells?
Thanks!

Hydrometer readings - what to do? | 12 comments (12 topical)

Re: Hydrometer readings - what to do? (3.00 / 0) (#1)
by Tom in NH on Fri Mar 04, 2005 at 09:06:24 PM MST

Here is my non-expert opinion. Run it through several charge/discharge cycles and see if that one cell starts to behave. Since you don't know if that one cell has a lower specific gravity because it is diluted with rainwater or because it is discharged, I'd run it through a couple equalizing charges to see if you can bring it in line. If not, then I'd consider fully charging the battery, dumping the acid out of all the cells, mixing it together, and then refilling the cells. Is your charger capable of giving equalizing charges? --tom

Re: Hydrometer readings - what to do? (3.00 / 0) (#2)
by zmoz on Fri Mar 04, 2005 at 09:20:39 PM MST

Well, since it's a starting battery and not a deep cycle, I don't think running it through any cycles would be very good for it. The one cell must have become diluted somehow, if not by the rain...there's no other reason the water level would be higher than the others, is there?

It's got a two year full replacement warranty, so I can allways take it back and get another, but that's allways a big pain in the ass with the geniuses at k-mart...

[ Parent ]

Re: Hydrometer readings - what to do? (3.00 / 0) (#6)
by Tom in NH on Sat Mar 05, 2005 at 10:25:02 AM MST

Wellll, Zmoz. Sincy you have a warranty, the solution is simple. A new fresh battery is going to be better than one that has sat out in the rain for six months any day. If it doesn't hold its charge, replace it. --tom

[ Parent ]

Re: Hydrometer readings - what to do? (3.00 / 0) (#3)
by tecker on Sat Mar 05, 2005 at 02:21:36 AM MST

Dump it into a supper clean 5 gal bucket check for sediment. Save the acid alow it to
sit in the bucket covered untill you have all the sediment settled and transfer the acid to a gal water jugs . Wash out the battery and dump that in a bucket save to dispose of away from the house and garden .Fill with distilled water and charge .dump out the water again and fill with the acid that you had . Not as good as edta but that
cast money.

Re: Hydrometer readings - what to do? (3.00 / 0) (#4)
by ghurd on Sat Mar 05, 2005 at 07:39:00 AM MST

I would just put it on a float charger for a week and see what happens.
Check the V 2x a day too make sure it is not getting past 14 or so (most chargers will, no matter what the box says).
But I am lazy. ;)
G-
Ghurd.info

Re: Hydrometer readings - what to do? (3.00 / 0) (#5)
by Shadow on Sat Mar 05, 2005 at 07:45:44 AM MST

I wouldn't be suggesting ANYONE be dumping their battery out into a pail! Unless you have proper protective clothing, gloves, Eye-wear,and do it in a safe location. One splash in the eyes can leave you blind!

Re: Hydrometer readings - what to do? (3.00 / 0) (#7)
by zmoz on Sat Mar 05, 2005 at 11:52:09 AM MST

So, why does the hydrometer say the other 5 cells are fully charged when they clearly aren't? I think I'll just hook the battery up to my truck and drive around with it for a few days...

Re: Hydrometer readings - what to do? (3.00 / 0) (#8)
by zmoz on Sat Mar 05, 2005 at 04:44:19 PM MST

Ok, I put a 1 amp charger on it for about 4 hours. I came back to find it overflowing acid onto my workbench. Now somehow a second cell is overfull. How did that happen? Is there any reason I shouldn't just remove a little of the acid from the overfilled cells?

Or, how about I just use the hydrometer to suck as much acid as I can out of each cell, mix it up in a jar, and put it back? Seems alot less messy and dangerous than dumping it into a bucket, though I wouldn't get all the acid. :-)

Re: Hydrometer readings - what to do? (3.00 / 0) (#9)
by monte350c on Sat Mar 05, 2005 at 10:23:53 PM MST

My vote would be for the warranty claim. Just tell them you tried to use it and the battery was spewing acid everywhere. (not far from the truth) Save your diagnostic skills for something with no warranty!

Ted.

[ Parent ]

Re: Hydrometer readings - what to do? (3.00 / 0) (#10)
by zmoz on Sat Mar 05, 2005 at 11:46:05 PM MST

Yeah, that's probably what I'll end up doing, but I'd like to try and fix it first. I've taken a battery back to k-mart before without a receipt, those idiots don't seem to grasp the concept of the "MFD DEC. 03" sticker on the side.

[ Parent ]

Re: Hydrometer readings - what to do? (3.00 / 0) (#11)
by Psycogeek on Thu Mar 10, 2005 at 02:01:06 AM MST

i would drain the whole thing, using 10-20lbs of baking soda to nutralize the acid, then buy a gallon of acid and refill it.
have done it before during a spill.
usually any time a cell hydrometer reading is less then the others, that cell is shot, and it makes the whole battery bad. usually the float is VERY similar, you can tell if one ball is about to float, or about to sink, so its quite analog even though its 5 ball digital.
IF it does have water in it from rain, i cant think how that would happen, then its probably recoverable.
it does not sound to promising, and it was weird that it was so well charged, mabey it was not so well charged, but that the "specific gravity" reding was effected by dilution with the water.
i cant remember what happens with the hydrometer in water, but YOU could check, test it in water, if all the balls FLOAT, then mabey they were floating just because the acid is DILUTE, not charged.

just more thought.

Re: Hydrometer readings - what to do? (3.00 / 0) (#12)
by Psycogeek on Thu Mar 10, 2005 at 02:07:40 AM MST

also, get a good flashlight, and LOOK inside, without getting any evil acid on ya, a LED light will light down low without lighting up the edge so you cant see, look into the battery and see if you can see the plates condition.
if they look all dirty (for lack of better words) and falling apart, or if they look all fresh and new. you cannot see very far, but you could see if its a mess, or if there is something growing in it :-)

Hydrometer readings - what to do? | 12 comments (12 topical)

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