Termination voltage for new deep cycle battery?

I have a new Walmart 27-series deep cycle battery, maybe 2 months old and working fine. I charge it religiously immediately after every trip with my 2/10/30 amp smartcharger.

I installed a small voltmeter in my battery box to help me keep a closer eye on the remaining charge. I've noticed that after the charger says it is "full" and stops charging the voltmeter reports 13.0 volts. Is that the right termination voltage for a new battery or should it be a little higher? I understand about surface charge but still thought it should be higher. :dono

Battery voltages

Attachment 167306

Does that mean I have 80% capacity left if my voltmeter shows 12.4v under load or at rest?

At rest or no load on the battery.

I have read recently that the only true way to determine if the battery is at full charge is to test it with a hygrometer....the old school way.
It seems that almost none of the modern automatic chargers will fully charge a battery.......To get a full charge, a trickle charger must be attached after the automatic charger is done and charge til the hygrometer shows a full charge......or just do that once and know how long it takes on the trickle charge.

A hygrometer use to be the best way before the digital meters were invented. Its pretty hard to read tenths of a volt on an analog meter.

Bob, yes, I have resorted to switching over to the trickle charger afterwards but this only increased the resting voltage a tenth or two.

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Originally Posted by Barnacle Bill

At rest or no load on the battery.

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Bill,

What does it mean then if under load the battery eventually drains down to something like 11.4v? It probably will go back up to something like a resting 11.7 or 11.9 volts? Is it Ok to run it into the lower 11v range if it goes back up to the ranges shown on your graphic at rest?

Its normal for the voltage to go down when the battery is under a load (being used). As long as it charges back up fully and stays there when not being used you are good to go. If you have any doubts about it take it to your local auto parts store and have them test it. Its free and then you will know for sure. They have some amazing equipment for testing batteries nowadays.

If the battery doesn't get back to a full charge, the life of the battery will be reduced.

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Originally Posted by wasabi

I have a new Walmart 27-series deep cycle battery, maybe 2 months old and working fine. I charge it religiously immediately after every trip with my 2/10/30 amp smartcharger.

I installed a small voltmeter in my battery box to help me keep a closer eye on the remaining charge. I've noticed that after the charger says it is "full" and stops charging the voltmeter reports 13.0 volts. Is that the right termination voltage for a new battery or should it be a little higher? I understand about surface charge but still thought it should be higher. :dono

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The final stage on most chargers is just a bit over 13V, so that's what the battery will read at the end or while the charger is in float mode.

Johnson Controls lead acid conventional flooded cell batteries are fully charged at 12.64V.

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Originally Posted by BobB

I have read recently that the only true way to determine if the battery is at full charge is to test it with a hygrometer....the old school way.
It seems that almost none of the modern automatic chargers will fully charge a battery.......To get a full charge, a trickle charger must be attached after the automatic charger is done and charge til the hygrometer shows a full charge......or just do that once and know how long it takes on the trickle charge.

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The idea that smart chargers don't fully charge a battery is a myth. The best way to determine the state of charge of a battery is to apply a voltage to the battery and measure how much current it draws. Since that is what chargers do, a smart charger always knows exactly how much charge the battery has. Most chargers shut off when the battery draws less than 1A. A trickle charger just overcharges the battery beyond its designed state because they don't monitor the battery state of charge.

Smart chargers are 1000% better than any other charger for fully charging a battery without shortening its life by overcharging.

I was told by a fellow that workd for O'Rilleys that when you have a deep cycle battery you need to charge it slowly. He said it is designed to give up its charge slowly and if you try to charge it at a fast rate it will damage the battery. Also that regular cranking batteries could be charged faster since they were designed to give up their power faster such as when you are cranking that big outboard.

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Originally Posted by BoarBuster

I was told by a fellow that workd for O'Rilleys that when you have a deep cycle battery you need to charge it slowly. He said it is designed to give up its charge slowly and if you try to charge it at a fast rate it will damage the battery. Also that regular cranking batteries could be charged faster since they were designed to give up their power faster such as when you are cranking that big outboard.

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Golf cart batts have dismissed his way of thinking for years, they get run down fairly slow but when charger is hooked up it throws the juice to em. I run smart chargers all the time, keep it plugged in on 4 banks.

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Originally Posted by BoarBuster

I was told by a fellow that workd for O'Rilleys that when you have a deep cycle battery you need to charge it slowly. He said it is designed to give up its charge slowly and if you try to charge it at a fast rate it will damage the battery. Also that regular cranking batteries could be charged faster since they were designed to give up their power faster such as when you are cranking that big outboard.

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Not even remotely true.

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Originally Posted by CatFan

The idea that smart chargers don't fully charge a battery is a myth. The best way to determine the state of charge of a battery is to apply a voltage to the battery and measure how much current it draws. Since that is what chargers do, a smart charger always knows exactly how much charge the battery has. Most chargers shut off when the battery draws less than 1A. A trickle charger just overcharges the battery beyond its designed state because they don't monitor the battery state of charge.

Smart chargers are 1000% better than any other charger for fully charging a battery without shortening its life by overcharging.

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So, if a smart charger is used and once it shuts off the battery only shows 80% charge with a hygrometer....then charge with a trickle charger for a few hours and the hygrometer indicates full charge....what is the reason for that?

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Originally Posted by Rees Guide

Golf cart batts have dismissed his way of thinking for years, they get run down fairly slow but when charger is hooked up it throws the juice to em. I run smart chargers all the time, keep it plugged in on 4 banks.

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Originally Posted by CatFan

Not even remotely true.

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Was just passing on what I had been told by the folks that deal with batteries everyday. I'm not a battery specialist and don't claim to be. I do batteries like this. If it is down I charge it and if that doesn't work I get another one. I do keep the cable ends clean though. A little care goes a long way.