Can Dead or near dead battery still give good SG and volt reading?

[paulcheung]

Can dead or near dead battery still give good SG reading and good voltage reading? I wonder if I carry a hydro meter and a volt meter. can it give me fair amount information to determine the battery is good or not. In Jamaica, it is a big hassle to return any merchandise. no dealer willing to take back any merchandise without big arguments.

I bought a battery Friday as it on sell for half price, the dear give the reason say they give these batteries by mistake. the wrong one did come and they can't returned them and they don't want these batteries run down. Hence the big sale.

The old saying is very true, that if something seems to be too good to be true, maybe it is not true. I carry the battery home, it reading 11.5 volts and 1125 on the hydro meter. I put it to charge for two hours at 15 to 20 amps. the still reading 1125 SG and the voltage drop to 8.5 volts. the battery is dead and not hold any charges. Lesson learned!

I hope I won't have trouble to get it replaced by another different type battery.

[inetdog]

Can dead or near dead battery still give good SG reading and good voltage reading? I wonder if I carry a hydro meter and a volt meter. can it give me fair amount information to determine the battery is good or not. In Jamaica, it is a big hassle to return any merchandise. no dealer willing to take back any merchandise without big arguments.

I bought a battery Friday as it on sell for half price, the dear give the reason say they give these batteries by mistake. the wrong one did come and they can't returned them and they don't want these batteries run down. Hence the big sale.

The old saying is very true, that if something seems to be too good to be true, maybe it is not true. I carry the battery home, it reading 11.5 volts and 1125 on the hydro meter. I put it to charge for two hours at 15 to 20 amps. the still reading 1125 SG and the voltage drop to 8.5 volts. the battery is dead and not hold any charges. Lesson learned!

I hope I won't have trouble to get it replaced by another different type battery.

The SG will give you a good idea of the current state of charge (SOC) of the battery, but it cannot, even in combination with the voltage, give you an indication of how the battery has been treated since it left the factory or how long it has been at that charge level.

If the SG is high, it is a very good sign, since sulfation will result in a permanent lowering of the maximum SG of the battery (unless an unscrupulous dealer tops off the electrolyte with concentrated acid instead of distilled water.)

But a low SG by itself is not necessarily a bad sign unless the battery has been at that low SOC for some time.

Of all of the possible indications without knowing the history, I would have to say that SG is the best single measurement.

[Sunking]

Sg will tell you about everything you need to know. I suspect you have a shorted cell from the voltage you gave.

[paulcheung]

Thank you, I guess the hydro meter will tell me if the battery is in good shape if the reading is higher than 1250?

[Sunking]

Thank you, I guess the hydro meter will tell me if the battery is in good shape if the reading is higher than 1250?

1.250 is a little low of around 80 to 90% I think. Do not have a chart in front of me. 1.265 to 1.275 is 100% @ 25 Celsius

Keep in mind that does not tell you if the capacity is at spec or not, it just tells you the battery is at 100% SOC. Capacity is determined by how much of the plates are left, and the only way to determine it is by a load capacity test which is really not a DIY project.

What is important to you is are the SG readings equal within .015 points. Look for any cell that is significantly lower. For example if 5 of the 6 cells in a 12 volt battery read 1.27 and one reads 1.23, walk away from that deal. When buying a new battery you want to see the SG up around 1.27 in all cells.

[paulcheung]

Understood, Thank you.

The problem is that these dealers have the battery sit down for few weeks or even few months without charging them. so it is not unusual the battery went down to 75%SOC. The one I got Friday gone is less than 10% SOC. can't even take any charge anymore.

Thanks again

[Sunking]

The one I got Friday gone is less than 10% SOC. can't even take any charge anymore.

It is a boat anchor Paul. Sorry you got robbed. Hope it was a cheap lesson.

[paulcheung]

I should be able to get it replace with something else, I won't want the same set of battery again. I keep my fingers cross. Hope he won't give me too much trouble get it changed.

Thank you.

[paulcheung]

Got it change to 2 trace 225amps battery, so now I have 450AH on that little system.
Thanks

[workpod]

Got it change to 2 trace 225amps battery, so now I have 450AH on that little system.
Thanks

Glad that your problem is resolved.

Still on the topic though if a near dead battery still good SG and volt reading.

Will a battery desulfator work and "resuscitate" these batteries to life?

For example, the batteries were kept being discharged to 50% DOD and below and is deteriorating with the evidence of white powder forming inside the cells. Could the battery desulfator revive these batteries?

[Sunking]

Will a battery desulfator work and "resuscitate" these batteries to life?

For example, the batteries were kept being discharged to 50% DOD and below and is deteriorating with the evidence of white powder forming inside the cells. Could the battery desulfator revive these batteries?

No sir. FWIW Lead Sulfate Crystals are brown. White crystals it a dead give away someone has used tap water to fill the batteries as that is hard water mineral deposits.

[ChrisOlson]

Will a battery desulfator work and "resuscitate" these batteries to life?

A battery desulfator is more commonly known as a battery charger. And yes, a battery charger will usually bring one back from the dead if it is simply self-discharged and became sulfated from setting around.

If you're talking about one of those little electronic pulsator boxes - no. They have never been proven to work.

I have brought totally stone dead (<8.5V) 12V deep cycles back to life that got that way from setting around. But it can't be done with a Farm & Barn off-the-shelf automotive charger that refuses to take the battery above 15.0V.