Is our 5yr old battery still good?

ChanW

Well, can anyone tell me, what's a better way to test it for 'aging'?

Our original Interstate 12V Group-24 "deep cycle/marine" battery seems to be okay still.

To test, I took it off the charger (normally continually connected to the trickle charger), isolated it from the Tab, let it sit for two days, and then checked the voltage. It still reads 12.8 volts (while still completely disconnected from the Tab).

As far as my understanding of dead or dying batteries, this one is still holding a charge, so it should be fine. Am I missing anything?

Is there a better way to test it? Maybe 'under load'? 

(I was really hoping to take advantage of the opportunity to upgrade to a twin 6-volt GC2 setup!)

rajamar

I bought one of these to test batteries:
https://www.amazon.com/Schumacher-BT-100-Battery-Load-Tester/dp/B000AMBOI0

MuttonChops

Most auto parts stores will test your battery for free.  They use a commercial duty version of something like seen in @rajamar link

ChanW

Yep, it seems folks have asked this same question here on the forum before, and I've always thought "let it sit for a few days, and see if it loses its charge".

But now that it's my turn, and it seems this battery ought to be getting cranky at this age, my simple test doesn't give me enough confidence!

So thanks, I appreciate the input!

jkjenn

ChanW said:

Yep, it seems folks have asked this same question here on the forum before, and I've always thought "let it sit for a few days, and see if it loses its charge".

But now that it's my turn, and it seems this battery ought to be getting cranky at this age, my simple test doesn't give me enough confidence!

So thanks, I appreciate the input!

The best way is with a hydrometer. You can test individual plates. 

https://deepcyclebatterystore.com/use-battery-hydrometer/

ScottG

My experience is mostly seat of the pants, but I've had a few batteries and have always been curious and attentive as to how they perform over their life

Holding a full charge over several is certainly a good sign--the higher that charge it "settles in" at, the better, and the longer it takes for that charge to diminish, the better.

As others have noted, taking and holding a charge is only part of the equation. Healthier batteries tend to deplete less under load. I bought a load tester at one point but found it so inaccurate when tested against my Fluke multimeter I sent it back. Now I just pay attention to how fast the voltage depletes while in use. Someday I'll get one of those hydrometers jkjenn mentioned, just to have another point of reference.

My bottom line is if my battery is still working for me, it's probably still good (or at least good enough).

I know, not much help when your lookin' for a reason to trade up...  ;-)

ChanW

 yeah, well....

I suppose I might do only half of the upgrade I had in mind, replacing the (perfectly good!) 20# propane tank with a pair of 10# tanks. Then when the battery dies, replace that with those two GC2 batteries....

That might be enough to satisfy me...

(Thanks for the suggestion @jkjenn. I guess I didn't realize that specific gravity was enough to go by)

ScottG said:

My bottom line is if my battery is still working for me, it's probably still good (or at least good enough).

I know, not much help when your lookin' for a reason to trade up...  ;-)

ScottG

@ChanW, it does seems like you have been exceptionally lucky with your original battery, so maybe you should just stop pushing your luck and upgrade now.  :-)

ChanW

There you go! Just what I was thinking!

(The moderator said to do it, so, of course....)

Thanks! 

ColoradoJon

Batteries can last much longer than 5 years!  The battery in my 2001 Dodge Ram Pickup that I purchased new in 2000 is still going strong

Edit:  That's 2000, not 200

ChanW

@ColoradoJon

Well yeah, I've sometimes had good luck, and sometimes not...

But never have I had a battery that lasted as long as 'since 200'!   
(Maybe that's a typo?) 2000?

ChanW

Okay, now I've taken @jkjenn's  advice and tested the cells with my handy-dandy hydrometer...

The battery came off the charger 3-4 days ago, and has been sitting disconnected.

Today, two of the cells tested only somewhat low, but another cell tested at 75-80%...

I'll do one more charge-up, with a good Deltran charger, and test it again, but I'm thinking @ScottG was spot on with his scientific diagnosis. "stop pushing your luck"!

Better to deal with it here at home, rather than on the road someplace, away from a Trojan dealer. 

ScottG

Yeah, I shoulda' been a consultant--always happy to tell people what they want to hear!  ;-)

BrianZ

I've read that all cells should have a specific gravity reading within 0.03.
Here's what Trojan says in their maintenance guide..