Probably having a multimeter is best way to check for both. You can find some that go for 5 bucks on sale.
Battery: check voltage drop over few minutes, hours, days to see if you get large change.
Alternator: check when engine on on battery terminals.


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I have a multi meter already. Thanks

 

Check battery voltage with engine not running. Should be around 12.5 volts. Check battery voltage with the engine running. Should be around 13.5 volts and higher. You should also have the battery load tested. Buy a load tester or bring it to a garage and have them do it. Good luck

 

Thanks. I did not know about load testing battery.

 

Yes, very important. A battery can test ok with a meter, then fail a load test because it has a bad cell. Check it for sure....Good luck

 

Kevcules. Is load testing a battery testing to see if any cells are bad. Also if you test the alternator with a multi meter and it test good the alternator could still be bad right.
Trying to find out if it’s the battery or alternator that is bad. Thanks.

 

Kevcules. Is load testing a battery testing to see if any cells are bad. Also if you test the alternator with a multi meter and it test good the alternator could still be bad right.
Trying to find out if it’s the battery or alternator that is bad. Thanks.

Esso is correct, these alternators last for a very long time.

Yes, load testing is for checking the cells in the battery. If you have even one bad, it will show on a load tester and should be replaced.

Honestly, the only test that I know for alternators is to check the battery voltage when the engine is running with a volt meter and or disconnect the battery when the engine is running. If you pull the cable off when it's running and the engine stalls, the alt is bad.

Like Esso said, what symptoms are you experiencing?

 

The alternator doesn’t seem to be an issue with these cars. Most, stem from battery. What are you experiencing right now?


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The alternator doesn’t seem to be an issue with these cars.

Esso is correct, these alternators last for a very long time.

I took my working alternator apart and to my surprise, at 405K miles the brushes still had a lot of depth to them. I was expecting them to be almost worn down, but they were still good.

 

Thanks again

 

What is a hydrometer for. Is that for checking if your battery has a bad cell. Thanks

 

A hydrometer is used to test the specific gravity of the acid/water mixture in the battery. A good spec grav should be around 1.275. Specific gravity refers to the weight of a fluid compared to plain water, so the closer the number is to 1.000, the closer it is to pure water, which indicates the battery is completely discharged.

CAUTION! YOU MUST WEAR PROPER PPE (personal protective equipment) LIKE THICK RUBBER GLOVES AND GOGGLES WHEN YOU OPEN THE CELLS OF A BATTERY.
If you get even a little acid on you, it can be very painful and will burn for a long time! I know from experience. If you do perform the hydrometer test, have a mixture of baking soda and water near by. You can use this to neutralize any acid you may spill. Check out this picture of a hydrometer for reference:

Now, as far as load testing, you dont need a load tester although it does make it easier. You can do a simple load test by holding your DMM (digital multi meter) leads on the battery posts, and having an assistant start the car. As the engine is turning over, observe the lowest voltage the DMM reads. If it is below 9V, then the battery is weak.

A simple test to see if the alternator is working is to turn the car key to the ON position. Grab something ferrous (a long screw driver works great) and touch the back center of the alternator. if you feel a magnetic pull on your driver, then the magnetic field of the alternator is working. if you don't feel any magnetism, then the there is a short in the field. Also check battery voltage with the car running. If it is below roughly 13v, then likely your alternator is not charging the battery.

If you really want to get into it, you can buy a battery tester on ebay or amazon for like $50.
ANCEL BST200: https://www.amazon.com/ANCEL-Batter...SZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

FOXWELL BT100 Pro: https://www.amazon.com/FOXWELL-FBA_...ndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

As other members have voiced, we may be able to provide better answers if we know what the car is doing. Is it not starting at all? Is it dying on the road? Does it start the car just slowly?

 

Aircraftmech. How do you test the battery for a bad cell. Thanks

 

If your battery cannot be charged beyond 10.5v, you have a bad cell. Each cell has approx 2.0-2.2v and there are six cells per battery. Try youtubing or googling "how to tell if your car battery has a bad cell". you should get a lot of helpful info that way.

 

Aircraftmech. Auto parts store test battery and alternator for free. They come out to your car. I just don’t know how good their test are. Thanks

 

I am aware of this, but assumed you had not had it done by them. Not to be rude, but if all you are trying to figure out is if auto parts store's battery tests are accurate, then you should have said so in the beginning. Yes, they are accurate to the best of my knowledge. Far more accurate than using a simple DMM, and they give you more information usually.

Are battery testers any good or it’s better to use a multi meter for battery testing. Thanks

Yes, depending on what kind of battery tester you get, most are of decent to good quality. FOXWELL is pretty well known for being a good brand, and a great alternative to buying an expensive tool truck quality one from Snap-On or MAC Tools.

or u can buy a battery and alternator tester and harbor frieght for less than 10$.https://www.harborfreight.com/12v-alternatorbattery-tester-63592.html

Buying that tester would be a waste of money. All it is doing is testing for voltage, and voltage doesnt tell the whole story when it comes to diagnosing electrical systems. For instance, suppose you have a battery that only shows 11.8 volts. This stupid little meter will say its bad, when actually, it could be a good battery that is just a little discharged. That is why battery testers that have some kind of load test function are far superior to this little thing. The ones I listed also test for SOC (state of charge), making them far more useful.

Everything this harbor freight tester can do you can do with a basic DMM. As already stated, youd be throwing away your money.

 

Are battery testers any good or it’s better to use a multi meter for battery testing. Thanks

 

If your keen on maintaining your own battery, the tester is best. If your diagnosing and doing quick maths, multimeter will tell you fairly quickly. Really depends on your end goal.

I know for sure by using multimeter 100% of the time. Both are good for their own reasons.


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or u can buy a battery and alternator tester and harbor frieght for less than 10$.https://www.harborfreight.com/12v-alternatorbattery-tester-63592.html

 

Question: is load testing when You put a load or a draw on battery to make sure the amperage is coming right back up to its level for performance. If it doesn’t come back. The battery is bad. Thanks.

 

Question: is load testing when You put a load or a draw on battery to make sure the amperage is coming right back up to its level for performance. If it doesn’t come back. The battery is bad. Thanks.

 

From the same source (I think) @AircraftMech406 used in post #12:

You can read the rest of the battery info from this link. It's just a few other points: Battery Load Test | Battery Capacity Test

Without a load tester, you can use a multimeter or the gauge on a battery charger. Turn on the headlights with high beams, radio, HVAC fan inside the cabin, etc. Watch the gauge on the battery charger or the reading on a multimeter. If it seems to hold well for a few minutes, the battery probably is good. If it seems to drop rather quickly, it's probably bad.

 

Aircraftmech. Thanks so much for your help and information I really appreciate it.
Also thanks for recommendations on battery testers. The only brand I ever heard of before was Midtronics. Thanks

 

Question: just asking. Battery testers do they load test a battery. I know they tell you the cca of battery but do they actually load test battery. Thanks.

 

When you load test a battery, the cold cranking amps (CCA) is a measurment of how well the battery performed. Therefore, if you have a battery tester that will tell you the CCA capacity of the battery, that is the load test. So the answer is: yes, battery testers that will tell you the CCA do actually load test the battery. That is how they determine the CCA.
I hope that made sense.

 

Aircraft mechanic. It made total sense. The only battery tester I heard of was midtronics
Thanks for help. I appreciate it.

 

Aircraft mechanic. It made total sense. The only battery tester I heard of was midtronics
Thanks for help. I appreciate it.

Bull6791, yeah I googled midtronics and the ones that came up were crazy expensive. I think a Foxwell or Ancel would work fine for your purposes.

 

I just really want you to know I appreciate your help.
The battery testers you recommended with the links were good. Thanks

 

I just really want you to know I appreciate your help.
The battery testers you recommended with the links were good. Thanks

Happy to help!

 

Aircraft mechanic. Since I never heard of Foxwell or Ancel and you already said Foxwell is a good name I will probably go with that one. Plus I think it has all the features I would need.

 

What kind of air craft maintenance do you do. Just asking because of the name aircraft mechanic. Thanks

 

Yes i agree, the FOXWELL will work great. I work on small piston engine airplanes. Mostly Cessna's.

 

Aircraft mechanic question: what are the actual features that I would need when buying a battery charger. Also would it be better for me to buy one of the ones you recommend or get an upgrade battery charger.
Hey what does 406 mean in your name. Thanks.

 

Aircraft mechanic question: what are the actual features that I would need when buying a battery charger. Also would it be better for me to buy one of the ones you recommend or get an upgrade battery charger.
Hey what does 406 mean in your name. Thanks.

What features you want in a battery charger depends on how much money you want to spend. If you just want a basic charger that will charge the battery in about 24 hrs, just get a NOCO from amazon for $30. https://www.amazon.com/NOCO-GENIUS1...Vgmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl
If you want something that can charge the battery faster, and is fancier, get a Schumacher. https://www.amazon.com/Schumacher-S...2/ref=sr_1_6?dchild=1&keywords=schumacher+battery+charger&qid=1610997884&sr=8-6

YouTube "best car battery chargers" and see what comes up. Those videos will give you a good snap shot of the features of each battery charger.

 

Sorry. I meant battery tester. What features would I actually want.
Should I get one of the one your recommended or an upgraded one. Thanks.

 

Sorry. I meant battery tester. What features would I actually want.
Should I get one of the one your recommended or an upgraded one. Thanks.

Just get the FOXWELL BT100 Pro. I am assuming youre a DIYer, and that tester will have all the features you will need.
The main features I would look for in one is that it tells you the following:

• It can perform a load test. This will tell you the cold cranking amps of your battery
• It can tell you internal resistance.
• It can tell you SOH (state of health) and SOC (state of charge). State of health is just a general score of the battery's heath. state of charge tells you if the battery needs to be charged.

The foxwell has all of these features.
The 406 is just a random number.

 

What does the 406 in your name mean. Thanks.

 

I really appreciate your help thanks.