I'm not a fan of those fancy impedance testers. I know they have their place but I wish they'd still keep the old style resistor tester so they can do it both ways
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- Thread starter shakenfake
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Perhaps what I should do after I leave it sitting for a couple of days outside is throw it in the truck by itself and see what happens. The battery that is in there now seems fine. I have yet to see the brake message on the dash.
That should give you some idea on it health. Let it sit for a few days. Then see how well that one battery can crank over the engine
Have you done a parasitic load test yet? To rule the out too
You might want to disconnect the negative on one of the batteries overnight and then test the next morning, checking both battery voltages. Then switch the next night and retest the other battery the next morning again. The 2 batteries should have almost the exact same voltage. I suspect they will not and you will find one of the batteries, maybe both, are bad. A shorted cell battery will often show great voltage, but no amps to power a starter or a carbon pile tester. Happened to me on a 6-month-old battery that didn't appear to have any problems, until it did.
@2004LB7 Not yet. I have been too busy to spend time on it. I do plan on doing it at some point.
@Ron Nielson I am not sure I follow completely. So put them both in but undo pos on one. Test in the morning and record data. Swap batteries (physically or just plug one pos in and remove the other one?) let it sit and retest. Am I checking with key on engine off or should I be trying to start the truck?
@darkness My dad was telling me about some battery tester/charger thing he bought. I'll need to make a trip over there and find out. I have no idea why he bought a battery tester other than our 4 (yes count them 4) battery chargers do not work in some capacity or another.
@Ron Nielson I am not sure I follow completely. So put them both in but undo pos on one. Test in the morning and record data. Swap batteries (physically or just plug one pos in and remove the other one?) let it sit and retest. Am I checking with key on engine off or should I be trying to start the truck?
@darkness My dad was telling me about some battery tester/charger thing he bought. I'll need to make a trip over there and find out. I have no idea why he bought a battery tester other than our 4 (yes count them 4) battery chargers do not work in some capacity or another.
Tonight I will try and start it on one battery (The one I believe to be the good one). If it starts I will leave it and check voltage at the alternator.
Next I will swap batteries and try to start it on the one I think is bad.
Next I will swap batteries and try to start it on the one I think is bad.
What you are trying to do is to test both batteries after being charged (after driving). They should have nearly the same charge. If you let the truck sit overnight, the batteries should retain their voltage. If you have a parasitic draw, the draw should draw down both batteries because they are both connected and in the circuit. But let's assume no parasitic draw. That makes it a little easier.
1) After driving, disconnect both negative cables. Do the voltage testing, and write them down - driver side, passenger side.
2) Next morning, do the testing again, write down the new voltages, and compare - they should be the same as the previous reading.
If one battery significantly changes voltage lower overnight, that's very likely your problem battery.
3) Attach the ground for one battery, crank the engine for say 10 seconds (or until it starts). If possible observe the voltage while cranking and write it down with your other test results. This puts an electrical load on the battery, just like a carbon pile tester would do. Check the voltage on the connected battery. Write it down with your other readings. Disconnect the negative cable on the tested battery.
On the other battery, attach the negative cable and crank the engine for the same amount of time. Check the voltage on the 2nd battery, and write it down with your other readings.
3) Compare the two tests. If one battery significantly changes voltage lower, that's very likely your problem battery.
You can do a straight voltage test with a volt meter. Test probes on the battery terminals themselves, not on the cable connector or outside of the cables. A carbon pile tester would be better but few of us has such a tester.
The purpose is to determine if one battery is causing problems but not the other. If both batteries have both cables connected you'll get a "combined" test result and what you want is an individual test result. I must say it is not imperative to wait overnight, but I was charging both of my batteries overnight and in the morning, the test would look 'good', both batteries fully charged, but within an hour it wouldn't start the truck. Now how could that be? One battery had a short and the way I found out which one was to do separate the battery testing. That's why when you take a dual battery vehicle for testing, they need to take one of the batteries out of the circuit so they are testing only one battery, then the other. And that's what you are trying to accomplish.
Test part one done here are the results
Key off: 12.47 both batteries
Key on engine off: 12.22 both batteries
After a drive (5-10 minutes with 5 minutes of idling and revving in the driveway), negative disconnected from both batteries, key off: 12.74 on the suspected bad and 12.91 on the suspected good.
Key off: 12.47 both batteries
Key on engine off: 12.22 both batteries
After a drive (5-10 minutes with 5 minutes of idling and revving in the driveway), negative disconnected from both batteries, key off: 12.74 on the suspected bad and 12.91 on the suspected good.
Now you wait at least a few hours. Best one day. Then measure voltage. And see if each battery has the strength to turn over the engine
Old school analog carbon pile load tester never let me down!!! I have the OTC 3181.
When I was in the shop, The #1 Failed battery was an Interstate, followed by the AAA batteries and the Autozone specials...
When I was in the shop, The #1 Failed battery was an Interstate, followed by the AAA batteries and the Autozone specials...
@1FastBrick I currently have three AAA batteries. One in my Silverado which has been in there for maybe 2 years now? And then these two.
Oh they are some crappy batteries... AAA always leaves the customer holding the bag too... You need to put an old school tester on it as James mentioned. If that battery has an issue, it will show you.
Got busy yesterday. This morning I checked the batteries, 12.45 on the suspected bad and 12.65 on the suspected good. Both went down about the same amount however that 12.45 is down below where I would think batteries should be charged at.
I did not crank them. Family should be here for the super bowl and I will get someone to record the meter while I crank.
Do yall have any recommendations for a carbon pile tester?
I did not crank them. Family should be here for the super bowl and I will get someone to record the meter while I crank.
Do yall have any recommendations for a carbon pile tester?
Been a while since I looked. I think Harbor Freight had one. Otherwise the OTC 3181 has served me well.
Not sure what others are using.
Not sure what others are using.
Dad brought his battery tester over and it is this one: https://www.amazon.com/ANCEL-BA101-Professional-Automotive-Motorcycle/dp/B01M0ARG3X
I'll have him record the cranking test.
I'll have him record the cranking test.
Well now it must be a draw for sure. 12.4 a few hours later when I went to check before I did the test.
One thing I must ask, does cold weather affect a batteries voltage? This is a condition that I only ever see in the cold. 40 or so. Right now I am actually NOT having the condition with only one battery attached. Gah so frustrating.
Anyway test results seemed to be normal operation. After starting the truck the battery voltage was about 12.05 on the "good battery"
One thing I must ask, does cold weather affect a batteries voltage? This is a condition that I only ever see in the cold. 40 or so. Right now I am actually NOT having the condition with only one battery attached. Gah so frustrating.
Anyway test results seemed to be normal operation. After starting the truck the battery voltage was about 12.05 on the "good battery"
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