Batteries Revisited

Here’s something maybe the more tech-savy IDAers can help me with. I sort of ignored my deep cycle (new last spring) over the winter( ) and am starting to get stuff ready for spring. On a side note, I definitely ignored the starting battery, but it’s 5 years old a due for replacement anyway.

In any case, last night I put the charger (an older one, and not automatic) on the deep cycle, ran it for a few hours at 10 amps, then switched it down to 2 amps and left it on overnight (on 2 amps). I checked it in the morning and the needle on the gauge was way down toward zero, so I am thinking it should be good to go. But just because I have a thorough side (and lots of toys that I don’t always get to play with), I put the flukemeter on it. 14.2 Volts! SO I am thinking, GREAT! Well, an hour later, I check the voltage again (because I am thorough and have toys I don’t always get to play with), and the voltage dropped to 12.7. I didn’t have it hooked up to anything, it was just sitting on a block of wood in the garage (temp in the garage runs about 35 degrees).

So my questions are: What caused the voltage drop under no load? Will the new automatic charger that I ordered at work but haven’t brought home yet “fix” it, ie. desulfate the battery if indeed that is the problem? Or did I just learn (or should I say re-learn) the lesson about not ignoring the boat batteries in the wintertime, and now I need to get a new one? Thanks in advance!

this is my two cents your battery should be at or around 12volts after cool down. when you check right after charging the acid is still perkulating. also on a deep cycle if you can put a 2 amp charge over night it will bennifit the battery more than if you through 10 amps at it right away. think of it this way you are drawing the battery down slowly there for to put the power back in slowly also another misconception that you need to store a battery on a piece of wood but that is not the case. in a pitch a fast charge can be used but hey you got all winter so slow charge once and a while. i just recently went to an interstate battery class and asked these very same questions and these are what they (the manufactures told me)

14.2 and dropping to 12.7 sounds like a good battery to me. What’s it read today?

Your battery sounds fine if indeed it is still holding a 12v charge. The reasons for keeping a battery charged through the winter, it helps prevent freezing if stored outside and also prevents dead spots from forming in the cell plates even if stored inside. Dead spots will decrease the running time and life of a battery.

You Guys rock. I learned somthing new here again today.

Just some thoughts. If it is 5 years old it is gone! I have taken batteries that showed charged that were not! Some batteries, maybe all, show charged but DO NOT hold charge because they are done!

The starting battery is 5 years old, not the deep cycle. I too have heard the block of wood isn’t necessary, but old habits can be hard to break…. I am glad you guys think the voltage drop isn’t cause for concern, and I’ll check it tonight after work and see where it’s at. Thanks, guys!

Required reading:

Batteries 1

Batteries 2

What you are worried about is if the battery is actually holding 100% of its capacity vs. just showing 100% voltage.

Easiest way to test? After charging it to full and zip on over to any pep boys or anywhere that can do a battery load test (always free). Then check voltage after 5-10 minutes of the Open Circuit Voltage against your batteries’ specifications. (need specifications as batteries do differ quite a bit)

Will tell you immediately if it holds a charge and is good. Can also buy a load tester for like $18 at any auto place if you already have a multimeter.

Yes, my concern is whether or not it’s holding it’s charge. I checked it again last night, after having sat for 24 hours, and it was still at 12.7 volts. So according to the first article (both of which were GREAT, by the way), I should still have a good battery. Thanks again.
Greg

Greg I use to have the same problem as you, batteries that sit to long because we forget about them until spring, here is what I did to fix the problem. You may have seen this before as it is an old post but just in case you did not……….

Here is a pic of my on board charger, it puts out 1.5 amps a very slow charge, I have two of them one for my starting battery and one for my 12 volt trolling motor battery. You can pick one of these up at fleet farm or Batteries Plus for around $29. This one works good for me because I do not fish every day so there is plenty of time between trips for them to charge up. This is also a good unit for when you store your rig in the winter as it will maintain and prolong the life of your batteries so you can get the maximum life out of them. I leave this unit hooked up and plugged in to my batteries all year long, I use to pull the batteries out in the winter and store them in my basement also (on a block of wood) but now I have OPTIMA Batteries. They can stay in the boat year round and they will not freeze up on you in the winter, but if you do need to pull your batteries out in the winter this unit is small and compact so its great to use when storing batteries in the basement, it does not make any nose and it is fully automatic so it will not overcharge. If you need to charge your batteries so you can use them every day several days in a row you will want to us a different charger for that.

So are you saying storing your batteries on a cold cement basement floor in the winter will not hurt them???

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another misconception that you need to store a battery on a piece of wood but that is not the case.

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Hi, let me tell you that a battery that shows charged is not the same as a battery that is underload! It is dead!! Trust me!

Steve- check out the two articles (links) above- they are great. According to both, leaving a battery on concrete won’t hurt it. But then neither will sticking a block of wood underneath!
As a side note, I checked my voltage again tonight and it is holding steady at 12.7. But I brought home my new automatic charger that has a desulfation feature and I am running it just to be safe. It’s actually a pretty cool charger, fully automatic 3-stage. Claims to do exactly what the above articles describe as far as charging and maintaining the battery. I’ll be curious to see how it performs.
I’ll also be curious to see what kind of shape the starting battery is in after having stayed in the boat all winter because I was when I put the covers on and forgot it was in there until both covers were locked down.