Reading my Hydrometer

[BradKW]

I've been playing around with the OTC 4619 Professional Battery Hydrometer I got last week and am frustrated because the float keeps sticking to the sides of the tube. It really takes barely a drop for the top of float to glue itself to the side...flick it free and it sticks to the other side   :/

So last weekend I cleaned it out and removed the rubbers so it would dry. This week I was careful not to draw too much fluid into tube and I got a good reading on 1st cell...but wasn't careful enough re-capping and switching to next cell and a drop got too high in tube and that was it. 

I mean, it kind of reads well enough when sticking that if you make it go up and down, you get a decent guess at where it wants to be...but nothing to bet the bank on. Hmm, that might be a pun.

Any advice?

[img=400x300]https://images-na.ssl-images-amazon.com/images/I/51Q34AW3f9L._SL1500_.jpg[/img]

 

[LeeRevell]

Is it a cheapo plastic unit or a glass one?

 

[SternWake]

I've never had that issue with mine. Mine likes to have bubbles stick to the float, but I have no issues with the float sticking to the sides of the glass cylinder.

Perhaps after rinsing, a little rubbing alcohol on the float and inner glass tube.

Twist bulb to get it off easy. I use some Syl-glide to make sure it does not fuse to glass.

 

[BradKW]

After a bit of googling, I found I'm not the only one with this problem, but nobody had a solution...just bitched about it in reviews.

I played around with it today and found a couple things:

1) the denatured alcohol is a good solution once the problem presents as it chases all the water out and the tube can then dry quickly with the bulb off,

2) filling the tube just enough that the float "floats" is important...filling more than necessary gets the glass tube wet high enough that the top of float can pick up moisture once liquid is squeezed out, and

3) Trojan recommends filling/emptying tube 4 times before taking a reading so thermometer reads correctly. Just filling enough to cover thermometer is all that's necessary...I was filling the whole tube, or at least a bulb fill.

 

[SternWake]

I just remembered I fat finger fumbled my original OTC float the first or second use breaking it, and instead used the float from a East PENN hydrometer bought at oreillys.  The EP hydrometer has no thermometer and the bottom plug falls off  the glass tube all too easily and would spill electrolyte, So I never trusted it, and got the OTC instead.


I wonder if one could carefully wetsand the glass tube with some 1200 grit sandpaper in a cross hatch pattern to perhaps break surface tension and keep the float from gluing itself to the sides of the glass tube.   Don't sand the float itself as it is too fragile and would change its weight if successful 

Since it is wet, it should not make it any harder to read the level if it gets a bit cloudy from the 1200+ grit sandpaper.

When EQ charging, and the batteries get hot, One can easily see the thermometer climb a little higher each squeeze and then actually feel the heat coming off the lower portion of the hydrometer.  the 4 squeezes are required just so the hydrometer warms up, and does not suck the heat from the electrolyte.

Also note the middle cell of your 6v L-16's get warmer, faster, than the outer cells.  HOnestly one can fudge adding or subtracting ~.006 too, after some familiarity and writing down the results on each cell for future reference.

But precision should be used initially to establish maximum wpecific gravity when fully charged.  Even though trojan Says 1.2XX? is 100% charged, you might find a cell which always reads a bit lower or higher no matter the electrolyte level.

It gets to a point where you can just Dip one or two cells and know where the batteries strand......in relation to that maximum expected reading you established when new and fully charged.

 

[Mobilesport]

I bought  the same OTC 4619 Professional Battery Hydrometer,
It came with  foam in it , i take it I'm supposed  to  remove  the foam?
I wasn't expecting  it  to  be as big as it is , from the pictures I saw I thought  it  would  be about  5 inches tall , it's about 11 inches tall , LOL

 

[SternWake]

Yes, remove the foam, and save it.

After you rinse the hydrometer well, and the float, carefully, then wrap the foam back around the float and slide it back inside, but make sure not to push it too deep so that you cannot grab it with your fingers.

Save the plastic and cardboard it came in and store it in that. You will have to slide the bulb all the way down the glass tube to get it back in the original package. Twisting the bulb from the end works better than a straight pull, and if you have any silicone grease, some of that lightly applied around the edge makes removing he bulb easy on the next use

 

[Mobilesport]

I remove  the foam  while  performing a specific  gravity test , right?
I'm thinking the acid would  eat the foam?
Thanks :shy:

 

[BradKW]

I haven't been re-packaging mine..so far I've had safe places to set it wrapped in a towel with the bulb off so it dries.

My initial problems were resolved by giving it a rinse of denatured alcohol, just sucking it in and squirting it back into container. Also important was pratice drawing in only the necessary amount from the battery, and being more careful to keep it upright while moving from cell to cell...

 

[Mobilesport]

Why's the foam inside the glass tube?

 

[BradKW]

It's just packaging to prevent the meter bulb from hitting the tube. I discarded it, but no doubt that if you take all SW's precautions every time when putting it away, you'll get a longerr life out of it. I'm more the type who would rather just buy another one when I break it

 

[highdesertranger]

"Why's the foam inside the glass tube?"
to keep the float from breaking while shipping. highdesertranger

 

[Mobilesport]

"Why's the foam inside the glass tube?"
to keep the float from breaking while shipping.  highdesertranger

I know it was a stupid  question  but I wanted to make  sure it ain't supposed  to be in there
during testing for some reason.
$17 is a lot of money  to me so I don't  wan t to break it
Thanks

 

[highdesertranger]

no problem Mobilesport. remember there are no stupid questions, only stupid answers. highdesertranger