Hydrometer Battery Tester

[Acosi151]

Hey folks,

It's a balmy -10F here today and expected to get colder, so yesterday I wandered around and gathered all the batteries out of everything I didn't need for the next little while and brought them in for a nice cleaning and overnight on the charger.

I also picked up one of these little guys

to attempt to see what I could find out about the condition of the electrolyte in each cell. I've never even topped up a battery before so I figured there's no time like the present to learn. Well.. I'm not sure if it's me or if these things are completely useless but I can't seem to make heads or tails of the readings. It seem extremely inconsistent, especially since I'm reading a battery I know to be good.

Anybody got any experience with this type of deal? I did a GJ search and couldn't find anything on electrolyte testers. Are these as useless as their price suggests? I think mine was $3. If so, is there anything the average backyard Joe can do while servicing batteries to get an idea of what shape they're in?

 

[joedodge]

Kinda old school when I worked at the transit garage they wanted us to use them all the time. They work well just read the scale for how many are floating. Just add distiller water I never really liked using them but still have one lol.

 

[theoldwizard1]

It's a balmy -10F here today and expected to get colder, so yesterday I wandered around and gathered all the batteries out of everything I didn't need for the next little while and brought them in for a nice cleaning and overnight on the charger.

I hope you were not trying to charge them all at the same time by connecting them in parallel. It will "confuse" any of the modern chargers.

Leave each one on the charger at least 12 hours, 24 better.

Anybody got any experience with this type of deal?

After charging, check each cell with the hydrometer. Fully charged should be about 1.265. More important is the difference between the cells. If the difference between the highest and lowest is more than 0.03, that battery is not going to have much life left.

 

[Acosi151]

Thanks for the tought on parallel charging wizard. I've acutally been tackling them one at a time though I see where I kind of suggest in my first post that I'm doing them all at once.

I've been leaving the car size batteries overnight on 6A and the motorcycle and lawn equipment batteries on overnight at 2A. I don't have a "smart" charger so I've just been watching the Amperage gauge. When it says it's pulling 0ish amps I'm pulling the battery off.

Using the hydrometer (it the floating coloured ball type) I'm getting one or two balls floating on a motorcycle battery that, before being pulled out of the bike, cranked the starter just fine. According to the gauge that means that the battery is near 1/2 charge? I guess a 'new' battery is setup to be lots more than the machine might need out of the box?

So, now lets take this motorcycle battery as an example. The Hydrometer is showing that it's at 1/2 charge after being on the charger all night and is known to turn over the bike's starter just fine.

Should I:

(A) Dump the existing electrolyte, flush the sediment with distilled water then refill with new acid and water
(B) Go pickup another battery, they're only $35 or so
(C) Put it back in the bike as-is, everything is fine

Also, in the past I've hooked-up a multi-meter to the battery then watched the drop in Voltage as I run the starter. Drop to 10ish volts during starting = OK, Drop to more than 10ish and probably time to replace the battery. Is there any truth to this? Would an electrolyte flush make any difference?

I know I'm departing from the "tools" theme a little here fellas. But hey.. my $3 hydrometer is only as good at the ninny running it right? Help a guy out?

 

[Drew_flux]

I dont think you can realy trust that tester. I would get one with a normal scale.Also are you allowing time for the battery to cool before testing? there is a calculation for temp v SG reading.

 

[rlitman]

SG varies with charge state and temperature. Hydrometers also vary in accuracy over temperature. That's one reason I don't really trust them. I have an ATC refractometer for testing. which will tell you the SG (really, an equivalent number) without having temperature issues, but it isn't something that I've found helpful much anyway.
If your battery is fully charged, and your hydrometer is showing half charge, something is wrong with your reading, and for most batteries (aside from huge ones) readings of the electrolyte's SG don't have much useful meaning anyway.

NEVER dump electrolyte out of a battery. NEVER add acid. ONLY top it off with distilled water to cover the plates. Anything other than that will hurt the battery.
Acid is only sold in stores, to fill brand new dry batteries. If you didn't buy a dry battery, do not buy battery acid.

If the battery seems to work, you can test it electrically. That tends to give the best estimate of a battery's longevity. I don't know about stores by you, but around here, Advance Auto keeps Midtronics testers in their stores. Those machines will print out a report about your battery's health. Ideally, you want to compare a reading now with one taken a year or two ago (or from when the battery was new), so you can chart the battery's deterioration.

Oh, and if you take a battery to a place that services stuff (garage, etc), expect to pay for battery testing. If you go to a place that ONLY sells car parts (strictly retail store, no garage attached to the side), they generally test batteries, test alternators, and pull engine codes for free.

 

[Lotek]

...
Oh, and if you take a battery to a place that services stuff (garage, etc), expect to pay for battery testing. If you go to a place that ONLY sells car parts (strictly retail store, no garage attached to the side), they generally test batteries, test alternators, and pull engine codes for free.

Just remember, at the parts store, generally you are going to get someone to push the button on the tester and read the results on the display, with an eye towards selling parts, a shop will diagnose the problem with an eye towards fixing the car, you get what you pay for.

 

[zmotorsports]

I am not a fan of hydrometers. They vary so much from one to another as well as the fact that they are very sensitive to temperature. I prefer to use a refractometer for batteries as well as coolants. Much more accurate and repeatable compared to the hydrometers and they compensate for temperature in the reading.

Mike.

 

[W650Mike]

SG testing is good to see if the cells are close to equal - an indication of relative condition, but not very conclusive. A load cell tester is better at determining a batts true condition...but it too can be somewhat subjective. The newer electronic load cell testers seem to give the most consistent and informative results but are expensive.

Hook up with your favorite parts house and have them test and show you what they are looking for. An honest parts man will spend a little time explaining the process and results.

 

[zmotorsports]

SG testing is good to see if the cells are close to equal - an indication of relative condition, but not very conclusive. A load cell tester is better at determining a batts true condition...but it too can be somewhat subjective. The newer electronic load cell testers seem to give the most consistent and informative results but are expensive.

Hook up with your favorite parts house and have them test and show you what they are looking for. An honest parts man will spend a little time explaining the process and results.

Good suggestion. I have the Midtronics tester but like you stated it is expensive and probably not economical for the average home/hobby use. I know our local NAPA will test them for free and probably even give you a printout if you asked for one.

Mike.

 

[theoldwizard1]

The best thing about using a hydrometer is determining if you have a bad cell. After charging it will have a much lower SG.

 

[honcho]

A refractometer is the best way to check the specific gravity of battery acids

sometimes referred to as a Duo-Chek

Mine is Leica (now Reichert) Here is a link

http://www.kerncoinstr.com/11j14.htm