Bringing Battery Back to Life?

[LittleBittyBigJohn]

Is there any way to bring a normal led acid battery back to life that just won't keep a charge? I have my brother-in-law's excavator at my house and it is in need of batteries. I have filled them with water and charged them. They will start it just fine soon after they are charged and they test good, but they will not hold a charge more than a week or so. I don't really want to have to put $400 worth of batteries in it if I can help it.

 

[BigBlue1]

Are you sure it is a bad battery versus a constant drain on the battery when the unit is off? Try disconnecting the battery cable after use once and leave it off until you need to use it again. If it fires up OK when you reconnect the cable there is a drain. If not, it is the batteries going bad. If the former, consider a master off electrical switch to use when unit is not in use.

 

[scootr]

Check the battery voltage before use and then again while the machine is running. The voltage should be higher when the machine is running, indicating the charging system is working.
Then disconnect the battery when done using the machine and see if they hold their charge by checking the voltage in 24-48 hrs.

 

[WranglerX]

Recent had to replace battery on generator, it had a battery tender connected to it, and voltage always tested good but when loaded (start button pushed) it went down to about 2 volts and only would spin generator about 2 revolutions and with generator running there was sufficient change voltage of about 13.7 volts..... Yes it was bad had no "capacity".... Put voltmeter across battery's (24 volt) and if it drops more the 3-4 volt cranking batteries have no capacity... Beside it is borrowed, fix problem before returning, so its $400, how much money did you save by not hiring out the work....

 

[WranglerX]

Check the battery voltage before use and then again while the machine is running. The voltage should be higher when the machine is running, indicating the charging system is working.
Then disconnect the battery when done using the machine and see if they hold their charge by checking the voltage in 24-48 hrs.

Always check voltage under load, its the real telltale sign of batter capacity, it should not drop more than 7-10% when cranking...

 

[John_Mc]

You say they test good after charging. Please describe your testing. If you are just putting a voltmeter on the battery at rest, that's not much of a test. Get or borrow a load tester and see what that says.

If you've got a bad cell, the voltage will usually drop down to 10.5 volts or so over several days (even if battery is disconnected from any loads). If you do have a bad cell, it's time for a new battery.

If it's not a bad cell, you might try charging with a battery charger that has a desulfation feature. Lead-acid batteries that sit in a state of partial discharge for an extended period experience sulfation, which slowly kills the battery. Sometimes a charger with a desulfation feature can bring these batteries back. It can take some time to recover them. (I recovered a couple that took a week on the desulfating charger to become usable again.)

 

[LS Tractor Owner]

You could take both batteries to an auto parts store and have them test "under load"..... and it's free!

They can also use a heavy duty charger which will de-sulfate it also.

That's the only way to tell if a battery is bad--- needs a load

 

[grsthegreat]

As said before, you need to test battery at 50% of cold cranking amp rating for 20 seconds or so. I use a carbon pyle tester for this.

I do generator maintenance as a retirement project. I take care of aprox 300 generators. When i find a battery that doesnt pass this basic test, i swap it out. Ill alert the owner first. If they dont want it done, i tell them not to call me when unit doesnt start.

This has stopped my power out calls for repairs.

I also use a Midtronics electronic tester to verify that there are no damaged cells.

Just testing voltage is useless on batteries.

 

[JasperFrank]

They are almost perfectly designed to last 5-7 years. Just buy a new one.

 

[5030]

I have master disconnects on both my Kubota M9 tractors and I use them every time I park them. They are on the NEGATIVE terminals not the positive terminals and you can buy them pretty cheap at any AP store or off Amazon.

NEVER top off any wet cell battery with tap water or well water or rain water. Always use DISTILLED water. Ordinary water has minerals in it that will degrade any wet cell battery and...

I change out my starting batteries in my tractors every 5 years no matter what. Wet cell batteries all degrade over time and will fail at the most inconvenient times and contrary to popular opinion, wet cell batteries will fail in hot weather more than cold weather.

Finally, keep the battery posts and clamps and the connections where they attach to the starter clean and bright and use a oxidation preventer on the posts and clamps and make sure they are tight and the leads not corroded or frayed. I use Fluid Film on my battery posts and clamps. HF sells a dandy post and clamp cleaner brush for under 5 bucks every day, get one and use it.