Determining if car battery has much life left

[paulri]

Some here have recommended that instead of simply monitoring the battery strength with a tester, I get a charger. I saw this at Pepboys.

Is this a cheapo unit that I should avoid?

Also, would this tell me the voltage on it?

And I would run this once a month or so?

 

[Wolf359]

You can get a cheap meter anywhere for around $10-$20. Your pepboys link didn't go anywhere.

Here's a basic charger on Amazon, about $25. You don't need anything crazy, an 8 amp charger will just take longer. Anything more than 10 amps isn't recommended anyway because a slow charge is better than a fast charge. You also didn't mention the type of battery, but most are anywhere from 40 to 80 amp hours so worse case is 10 hours, however even if you kill the battery by leaving the lights on, it's probably not at 0 amps and should come back after a few hours.

https://www.amazon.com/Schumacher-SC1279-12V-Rapid-Charger/dp/B07DM22XTN

 

[paulri]

Sorry about that, here is the correct link: https://www.pepboys.com/peak-10-amp-intelligent-battery-charger/product/1873274?

 

[paulri]

The battery that I was asking about earlier was a Toyota TrueStart battery, #00544-51R60-500. It has 500 CCA, and a reserve capacity of 85 mins at 80 degrees.

However, I'd also use it to monitor/charge a Walmart Everstart Maxx 24F battery in the Sienna, with 750 CCA.

 

[wag123]

The cheap load testers will only tell you if the battery is already bad (or VERY close), it won't really give you any indication of how much longer it will last. A conductive tester (battery analyzer) like Donald referred-to will give a better idea of how much life is left in a battery.
In Texas, every one of the batteries that have gone bad on me in the last 40 years have been fine and then failed without warning, like a light bulb burning-out. Ultimately, having a portable jump starter box in the car with you (kept fully charged) is probably the best way to squeeze the last life out of a battery without having to worry about getting stranded somewhere, but, many new cars will not run very long after being jumped because they have battery excited alternators. My rule-of-thumb is this... if the battery is older than 3 years old, you are living on boroughed time.

 

[paulri]

If that is the case, then I think I'd be wasting my time if I just get a load tester. The conductive tester I saw online was more than the price of a new battery. I think I might just go with a jump n carry, that will allow me to take my battery to the point where they conk out, although even the one linked to by spavel6 costs more than the battery in the sienna, so again it would take a while for it to pay for itself.

Well you folks sure have given me a lot of food for thought, as usual.


Originally Posted by wag123
The cheap load testers will only tell you if the battery is already bad (or VERY close), it won't really give you any indication of how much longer it will last. A conductive tester (battery analyzer) like Donald referred-to will give a better idea of how much life is left in a battery.

 

[Wolf359]

Originally Posted by paulri
Sorry about that, here is the correct link: https://www.pepboys.com/peak-10-amp-intelligent-battery-charger/product/1873274


I guess spec wise it's fine, but the other one I mentioned might be a better maker although you get negative reviews with any battery charger. As others said, you don't even need to buy a load tester, most auto parts store do it for free. And if you have a meter, take the battery out of the car, put it on the charger and then check the voltage. As a battery gets older, it won't be able to retain a charge so you can refer to a state of charge chart to tell what percentage the battery is charged up to. That requires a no load voltage at 70 degrees in order to use the chart properly. When it's connected to load like the car, the voltage will always be lower.

Oh here's your cheap Sears $9 meter.

https://www.sears.com/craftsman-multimeter-034821410000/p-A028300107