battery charger

[ddilman]

I have a 2005 Catalina. I am not able to get my batteries charged more than 12.5 volts. I used to be able to charge them to 13+ volts. Could this be related to my battery charger? What's the typical life of batteries?

[SteveInMD]

Can you provide a little more information? A fully charged lead acid battery has a resting voltage around 12.7 volts. That means after 24 hours with no charge or load on the battery it should read 12.7 volts. Your charger should provide a maintenance or float charge of about 13.4 volts. Are you reading voltage during charging or resting? What type of battery is it?

With careful care you can get 10 years from a battery. Depending on the battery type, five to eight years is more common.

[KindOfBlue]

There are lots of factors that can influence battery life and how much charge they can take. A few things to consider.

How did you measure 13+ volts? Your gauge could have a lose connection. Have you used a multimeter to verify?

How long after removing the charge did you record 13+ volts? The surface charge will absorb into the battery after you remove the source. The gauge will read the surface charge and as it absorbs it will equalize and record the real charge hours later.

Has your charging method changed (alternator, shore power, wind, solar, etc.)? 3 stage charger is going to give the best charge and some charging methods will only give you 80% charge.

If you discharge your batteries below 50% you could lose the top end capacity.

What type of batteries do you have (maintenance free, wet, gel, etc.)? If not maintained correctly you will lose top end charge capacity.

Have you ever over charged your batteries? Over charging wet batteries causes them to bubble. You would need to top off with distilled water or you will lose top end charge capacity.

If maintained correctly, your batteries should still be in very good condition in the 4th season.

[camaraderie]

My guess is that you have standard wet deep cycle batteries and a basic charger and are now seeing the effects of a poor charging routine and sulfation in your batteries. BTW...12.6 volts is fully charged but when depleted you youd see your charger operating in the 13.3-14.5V range and the battery should measure 12.6 AFTER charging and sitting at rest for some hours.
As the prior posts said. We need to know your charger type, battery type and size and alternator type to be of real help.

[saurav16]

I do not believe it is possible to get 13V from the battery... It is a 12 V battery. It has 6 cells each cell producing approx 2.1 V each therefore giving you 12.6V total at full charge.

[seabreeze_97]

A fresh "12 volt" battery can exceed 14 volts in top form. As batteries age, the lead plates become sulfated. Loss of surface area on the lead plates reduces maximum potential. I have had real, tangible improvements using this little dude: Model 12117 12V 1.33Amp
At first glance, the time required to revive a battery seems impossibly long (from days, to weeks or months), but they're just sitting there anyway. I now regularly rotate my batteries to keep them all at their best. Best price I've seen is around $45.

[btrayfors]

Originally Posted by seabreeze_97

A fresh "12 volt" battery can exceed 14 volts in top form. As batteries age, the lead plates become sulfated. Loss of surface area on the lead plates reduces maximum potential. ...

Any 12 volt flooded battery, at full charge, will not measure more than about 12.7 volts once the surface charge is bled off (by sitting overnight). Doesn't matter if it's new or not.

VRLA batteries (gels and AGMs) will measure about 0.1 - 0.2 volts higher at any state of charge.

Loss of surface area thru sulfation does not significantly affect maximum potential (voltage). A badly sulfated battery will still show a "normal" voltage immediately after charging. What is affected by sulfation (and corrosion and stratification and contamination, inter alia) is battery capacity.

I believe seabreeze meant to say "potential for delivering power" or some such, referring to available amp-hours, not voltage (for which the technical term is "potential").

Bill

[saurav16]

Btrayfors is abs right... When you charge a battery and get it to full charge there is a latent surface charge that remains. This charge gives you a reading of higher than approx 12.6 V (2.1V per cell at 6 cells). After a few ours this surface charge will dissipate and you will see your charge 12.6V.

[sailingdog]

You can also dissipate the surface charge by applying a load to the batteries for a short time IIRC.