12v batteries reading 14.18v

[Naio]

Yep, it's me, back with another question :-).

I double checked the voltage with a second voltmeter, and checked the first voltmeter on another battery. It seems that the 14.18v is reasonably accurate.

Does this mean something other than that my charger decided to overcharge the batteries?

Thank you for any insight.

[Naio]

They have been an awesome pair of batteries!

I hope I haven't shortened their life too much by this recent incident. But so far, every time I think they are on their way out it turns out my problem is something different. They are cold, or the charger is going or something.

I cannot tell you how many chargers I have gone through with this one set of batteries. They drop like flies, but the batteries keep going.

[profdant139]

Are these really 12 year old batteries? And they are still doing the job for you, in a commercial application? (I'm assuming the shave ice is not just for you alone!)

If the answer to both of those questions is yes, congratulations and keep doing what you are doing!!

One more thought -- you mentioned the ammeter -- using the ammeter when the device is running is (I think??) the only way to get an accurate reading of the current draw.

[MrWizard]

Never heard of anyone adding water to "gel cells"
I have read of people doing it to AGM cells
With AGM it has to be done a little at at a time ,usually with a syringe, as the water has to percolate down thru into the glass mat
Aka be absorbed into the glass mat holding the electrolyte

[Naio]

I have an ammeter, but trying to use it when the machine is under load would be pretty darn difficult.

I've had this particular pair of gel batteries for a dozen years or so, and I got them used. I've never seen a resting voltage above about 13.10 before.

They were 12.77 volts this morning, so I charged them gingerly for about half an hour, then used it a little bit, and charged again for about 10 minutes. Will see what the voltage is in the morning.

landyacht, do you think I should try to add water to these batteries?

One of the pair tends to have some electrolyte leaking around one of the terminals. It's done that for the whole 12 years I've had it. I clean it off once in a while. The other one does not normally do that, but it does have a tiny bit of leakage now since the giant overcharge.

I think you said you have to drill a hole to add water? I'm pretty hesitant to mess with them.

[BFL13]

Any solar?

[landyacht318]

A 12v battery reading 14.18v open circuit, rested, 18 hours removed from the charging source @ 50 degrees F, is not right.

I've no experience with Gel batteries but I expect I would have read something about their incredible surface charge retention, if it is actually true, in the 2 decades I've been reading about lead acid batteries and experimenting and collecting data on their performance.

What one mostly reads on gel batteries is their incredible cycle life when charged properly, and their premature death when not charged within their well published parameters.

Don't praise your charger yet, see how the batteries perform the next time.

As I said every time I noticed well above normal surface charge retention with my flooded battery, some of the cell's plates were exposed, and once refilled properly That voltage retention ability was erased along with some portion of the battery capacity, never to return. I imagine voids in gelled electrolyte could do something similar as low electrolyte levels on a flooded marine battery.

Get a clamp on ammeter. Guessing sucks and actual numbers/data rule.

[Naio]

Thanks, time2roll, I didn't realize that! Although I'm talking here about the voltage on the battery posts 18 hours after charging. But I'm glad to know that my charger is not as **** as I thought.

[time2roll]

I call normal on this one. I see charging specs at 14.4 to 14.6 for MK Gel.

[Naio]

Thank you, folks.

They are gel batteries, not AGM. They are reading at 14.18 volts each. I didn't realize a charger could overcharge them that badly :(.

They performed well yesterday in a long run, thank goodness. I will see what their voltage is this morning, after the overnight rest. I did not charge them today after use.

I don't think I can get an amp reading off the motor when it is overheating. I don't want to put it in that state again if I can help it. I can tell you my 100-amp breaker did not trip.

[wolfe10]

You need less "run time" for the charger. 14.18 VDC is fine for charging, but high for float level. Yes, it will overcharge the batteries.

Set the timer to run it fewer hours a day.

And, as said, check the voltage a couple of hours after turning off the charger and hopefully not running a load. That will give you an indication of how much charging needs to be done.

The other VERY GOOD way to tell if more/less charging is needed is to measure AMPS that the charger is sending to the batteries. If below 5-8 amps, you don't need to keep charging.

[MrWizard]

Gel batteries have very specific charging requirements
You must not apply over voltage to them, the same applies to over current discharge
They heat up to gassing point you voids/cavities in the gel electrolyte

[landyacht318]

So your two 12v batteries in series, are reading 14.18v together?

Meaning each 12v battery alone ....is reading 7.09v?

If so, that's not a good sign.

Are they gelled electrolyte, or AGM. Sooooo many people call any sealed battery a gell cell that the term has now become entirely meaningless without actual clarification that one knows the difference.

If they are actual gelled electrolyte batteries, I have no experience with them, If each is measuring 14.18v, and together in series they are measuring 28.36v, 18 hours off the charger, perhaps your e bay charger took them way over the 28 to 29 volts you previously measured, overcharging them, perhaps causing voids in the gelled electrolyte, the bane of actual gelled electrolyte batteries.

Would be nice to see how much amperage your overheating 24v motor is drawing, and know how much voltage it is getting.

Without Data or proper details you will not get anything but random well meaning guesses.

[Naio]

Apologies for the lack of detail. I forget sometimes that people are not seeing what I am seeing :).

These are the batteries for my shave ice machine. I charge them with an off-the-shelf 24 volt charger I got on eBay. I don't think it is doing any fancy anti stratification cycle. It's too simple for that. The batteries are gel cells, MK brand.

They are reading 14.18 volts after being off the charger for about 19 hours. The ice machine is outside. It was about 28° last night and daytime temperatures have been around 55. I don't have a temperature measurement for the batteries themselves, but I would guess around 40 or 50. I keep a heating pad on them at night.

I've had the charger for a few years and it has always put out a bit higher voltage than I would like. I think it's 28 or 29v. I am not there right now to measure it.

I charge on a timer, based on usage and past experience. I have maybe been overestimating the time that I should have the charger on.

But still, should the batteries be this High 18 hours after charging?

Today I used the machine a lot, and then did not put it on the charger. I'm going to see what it reads in the morning.

Also today, my recently inspected motor overheated again! Could the batteries have anything to do with this?

[landyacht318]

Every time my workshop relegated aged flooded marine battery would read and maintain a high surface charge of 13v or higher many many hours off the charging source, I knew it was low on water.

Seems some responders think you batteries are still on the charging source, reading that voltage, so perhaps some clarification is needed, for them.

I've never seen surface charge retainment over 14v for more than a minute or 2, on any 12v battery. So how long off the charger are yours maintaining 14.18v, and what is their temperature?