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Technical Battery Testing

Discussion in 'The Hokey Ass Message Board' started by blowby, Dec 27, 2017.

  1. blowby
    Joined: Dec 27, 2012
    Posts: 7,514

    blowby
    Member
    from Nicasio Ca

    Hydrometer vs. Voltage vs Load Testing

    Like many of you I have many vehicles, beyond my two hot rods. I keep a half dozen batteries on the bench with the charger, some that belong in a vehicle and some spares, and pick the worst one when it's time to trade in a core. Here's what I'm finding:

    Any battery that won't hold 12.5 volts is the first to go. But some that hold voltage, have high hydrometer readings fail a load test (common hand held load tester). Other batteries with low hydrometer readings still pass load testing. What gives? All are about the same size, group 24 etc..
     
    lowrd likes this.
  2. The hydrometer is supposed to tell you level of charge and cell to cell comparison. Each cell shouid be even to the others

    The load test is a replication of real life experience for the battery. it should pass 3 consecutive load tests. A surface charge can pass a load test
     
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  3. 1940Willys
    Joined: Feb 3, 2011
    Posts: 533

    1940Willys
    Member

    Where I'm From we have another test, Mother Nature. Temps get down below zero and chill factor even lower than that. Although I think Chill factor only has to do with humans. I'd go with the load test as in my mind as it most replicates the key in ignition turn thing. Hydrometer readings measure specific gravity. I don't know if this means charged electrons or just the way the electrolyte is deluted. I'm interested to find out more too.
     
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  4. squirrel
    Joined: Sep 23, 2004
    Posts: 48,679

    squirrel
    Member

    The hydrometer test tells you the state of charge. The load test tells you the reserve capacity of the battery.

    They are two separate things.
     
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  5. blowby
    Joined: Dec 27, 2012
    Posts: 7,514

    blowby
    Member
    from Nicasio Ca

    Well that narrowed the field. Never tried that. By consecutive you mean like 5 seconds on, 5 off...like your trying to start a pesky car. Some handle it fine, some go in the yellow on the third try.

    So other than comparing cells no different that a voltage reading?

    Thanks guys.
     
  6. Truck64
    Joined: Oct 18, 2015
    Posts: 4,624

    Truck64
    Member
    from Ioway

    What is a hand held load tester? Conductance testers are popular for warranty service determination, is that what you mean?

    A valid proper load test with a carbon-pile requires a full charge on the battery first. And re-charging after it's over, too. Nobody wants to take the time do that, and the conductance testers are handy and quick. If a battery passes with a conductance tester it "might" be OK, but if they condemn a battery it's almost certainly bad.

    Some of your batteries probably have some level of permanent sulfation. They will never charge back up normally, it's like trying to wash your hands wearing rubber gloves. Keep them charged up to 100% whenever possible and keep in mind this is 12.80 volts for sealed, maintenance free batteries, and this figure (as well as charging voltages) are very much temperature dependent.

    People who don't know any better don't like to see 15 volts + on their charger in 0° weather but that's what it takes in the cold just to break even. My latest and greatest Schumacher charger displays "12" on the digital display at all times regardless of the actual charging voltage at any given time. Fewer warranty returns that way probably. LOL!!!
     
    blowby likes this.
  7. blowby
    Joined: Dec 27, 2012
    Posts: 7,514

    blowby
    Member
    from Nicasio Ca

    My load tester is just like this. My charger (Schrader I think) has red green and yellow lights. Yellow it's charging, green at about 13.5 volts, red and the battery is toast.

    upload_2017-12-27_10-3-26.jpeg
     
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 48,679

    squirrel
    Member

    The load tester mostly checks for permanent sulfation, which is just the natural "aging" of a battery.

    Keeping a battery in constant use seems to be the best way to make it last for it's designed life. I like to replace them after five years, because that seems to be about the time that they start to lose enough capacity that it can be a problem.

    Any battery that will not be used regularly, should be charged regularly, and never allowed to discharge very far, for very long.
     
  9. Load test is supposed to be 10 seconds.

    If it goes yellow,,,doesn't it say to charge and try again? So charge it and try again. My yellow range is pretty wide sweep too, 10.5 to 6.5 volts before the red/replace.

    The hydrometer is the only way to check the condition of individual cells.
    Any other method is an average or accumulated across all cells
     
  10. Los_Control
    Joined: Oct 7, 2016
    Posts: 737

    Los_Control
    Member
    from TX

    Seems that people whose hobby involves cars involves "extra" cars that sit around a lot.
    Need extra batteries to keep them going.
    Sqirrel gives great advice about keeping them charged, does not always happen.

    What about batteries that die prematurely, because they sit to long without being used.
    On the internet, you can see others will drain the battery acid out into a bucket, comes out black and dirty. Then a mixture of baking soda and water to clean the battery, beat on the sides and knock all the crap loose and drain and repeat a couple times.
    Then for some reason they use epsom salt and water instead of new battery acid, a slow 2 amp trickle charge for 48 hours, and revive the battery.
    Baking soda and salt is a couple dollars cheap investment on a $75 replacement.
    Anybody try this and have good luck?

    I would probably not want this in my daily driver I have to depend on, but for the lawn mower and extra batteries needed to start the extra cars etc... the cost adds up, and you still let them sit around if they are new or not.

    I have not tried it yet. One thing bothers me is disposing of the old battery acid.
    Same people claim diluting it slowly with more water and baking soda will neutralize it, and can safely pour it down the drain flushing with plenty fresh water ... I think local waste management will accept if properly labeled also.
     
  11. squirrel
    Joined: Sep 23, 2004
    Posts: 48,679

    squirrel
    Member

    I wish I had a way to make it happen, always. But regular preventative maintenance seems to be the most difficult thing for us to do!
     
  12. 28dreyer
    Joined: Jan 23, 2008
    Posts: 1,164

    28dreyer
    Member
    from Minnesota

    Charge the battery fully
    Turn on headlights for 3 to 5 minutes or so to knock off surface charge.
    Connect volt meter to battery.
    Leaving headlights on, disable ignition, and crank engine for about 10 seconds.
    Battery needs to maintain 9 volts under this cranking and lighting load.
    If not, you have one or more weak or dead cells in the battery. each cell needs to maintain 1.5 volts. 1.5 X 6 cells = 9 volts
    In the old days batteries were made such that the cell connections were accessible through sealing goop on the top of the battery and many of the hand held load testers spanned only one cell at a time.
     
  13. Truck64
    Joined: Oct 18, 2015
    Posts: 4,624

    Truck64
    Member
    from Ioway

    That stuff coming out is toxic as hell, the electrolyte acid ruins your clothes, and while it's a little rare batteries do explode now and then during charging &c. I just use them till they die, and then go buy a new one. It's not worth the trouble for me. Trying to wring every last electron out of them is hard on the car charging system too.

    I am a believer in external chargers, it is amazing how long batteries last despite the abuse heaped on them by most. That's probably why they cost $150 today instead of $50, like they should.
     
  14. blowby
    Joined: Dec 27, 2012
    Posts: 7,514

    blowby
    Member
    from Nicasio Ca

    4 beater work trucks, 3 smokey tractors, 2 running hot rods and a daily for the wife and me.:)
     
  15. squirrel
    Joined: Sep 23, 2004
    Posts: 48,679

    squirrel
    Member

    We're down to only five...plus the trailer, but it has solar panels on the roof. I try to drive all the cars at least once a week, but it doesn't always happen. Must be that much more difficult for the guys up north in the cold.
     
  16. 2.14 volts is a fully charged cell 1.89 is completely discharged .

    Electrolyte specific gravity tells you state of charge only.

    A load tester like the one above works great, carbon pile tester is better.

    You need to “ burn off” any surface charge the battery may have before load testing. This can be done by turning on the headlamps for a minute or two or doing two load tests with the toaster oven load tester.

    Batteries surface with aging and incorrect charging. Fast charging is bad slow low amp charging and cool down after charge and before use is optimal.

    Sometimes a weak battery can be brought back with a forming charge, long slow charging ( 3-6 Amp over a long time) can break up sulfication and keep a battery useful for longer.


    12 volt battery can’t drop below 9.5 volt under load.
    A 12 volt battery at 12 volts or less is discharged. 12.5 and above is where you want your battery.

    A battery is only as good as it’s weakest cell. A bad battery or cell is going to cause the alternator or generator to work harder, starter motor to work harder more heat and amps through wiring and electronics etc.


    For what it’s worth I replace mine every 5 years and use a battery tender on stuff that does not get driven regularly.

    If you need to mount your battery sideways a AGM battery is good
    Otherwise a quality wet acid battery is just fine.


    From what I’ve been told there are only 2 or 3 battery manufacturers world wide. Maybe a few in China making garbage, don’t know.
     
    blowby likes this.
  17. And how are you supposed to check the electrolyte level in those "maintenance free" batteries? I'm sure plenty of life could be squeezed out of them if you were able to access the cell to top it up. Usually ends in a mangled battery lid.
     
  18. squirrel
    Joined: Sep 23, 2004
    Posts: 48,679

    squirrel
    Member

    You are not supposed to check the electrolyte level. It will be fine for the design life of the battery, as long as you treat the battery well.
     
  19. blazedogs
    Joined: Sep 22, 2014
    Posts: 469

    blazedogs
    Member

    A little off the subject, sorry I have 3 ( battery tenders), Schumaker brand that I use. Just for the heck of it after the green light comes on on the tenders I checked the voltage on the battery and it,s never over 12.5 volts. I,ve done all three tenders and they are all the same. So if I'm reading it right, tenders never charge a battery to full charge being about 13 v What gives??? Gene
     
  20. There's an answer for everything
    Continue at your own risk.

     
  21. blowby
    Joined: Dec 27, 2012
    Posts: 7,514

    blowby
    Member
    from Nicasio Ca

    I haven't seen anyone with a lithium battery in a car yet but they are getting popular in motorcycles.
     
  22. Blues4U
    Joined: Oct 1, 2015
    Posts: 5,560

    Blues4U
    Member
    from So Cal

    I used to do similar to that quite a bit, when I worked at a dealership and had access to a pallet full of old batteries. I'd pick the nicest looking ones of the right size and dump them upside down and let them drain out, then refill them with fresh battery acid (we had a large plastic tank of it), and put them on a trickle charger for a couple of days, and if they came back up I'd use them in something. Many of them (most?) would come back up and would work, though they never had full reserve capacity any longer, but hey, they'd keep me going.
     
  23. I've got one in my Mom's OT hot rod. It works just fine.
    Weird picking it up and it weighs less than the Box it comes in.
     
  24. Truck64
    Joined: Oct 18, 2015
    Posts: 4,624

    Truck64
    Member
    from Ioway

    Depends on the type of battery to begin with. The sealed maintenance free batteries have a little bit different chemistry than the classic flooded lead-acid with the caps on top to fill each cell. One thing the average non-H.A.M.B. person doesn't know is "12 Volts" even may not start the engine, depending on how cold out. The difference between 100% and Flat Dead is less than a single volt.

    A fully charged modern automotive battery is a lot closer to 13 volts than 12 volts. Anyway, those tenths don't sound like or seem to matter a whole bunch, the engine starts right? But they matter a whole bunch when it comes to maximizing performance or longetivity. A standard lead acid is charged at 12.65 volts, but a sealed MF is 12.80 volts. What kind of battery do you have?

    The reason it makes a difference is because if you have a maintenance free battery 12.5 volts across the terminals is around 60% charged - charge tables are different and the sulfation that forms quickly turns permanent. If it's a standard battery that's better, but still off the beam. With me so far? OK, the tenders are designed to maintain an already charged battery, or nearly so. They are flea powered and usually less than a single amp.

    So they have protection circuitry designed to automatically switch to a float charge after a certain amount of time passes. Otherwise, they would be bubbling away for a week and a half trying to get that last 10% charge in, and they'd soon boil dry. I use the "dumb" chargers to get them good and charged and then store them on the tenders. Moderate outgassing or bubbling is necessary for re-charging, but it has to be minimized. This is why a charger is "sized" to the battery. Heavy current can warp plates, but a slower moderate charge is more thorough. The tenderizers are too small to efficiently bring them up to where they should be. A whole lot better than nothing though for sure.

    Can try to "reboot" the smart chargers by un-plugging and plugging them back in repeatedly. But see above. The idea when charging is to minimize the amount of time spent outgassing. Bulk phase; absorption phase, etc. The tiny tenders aren't designed for neglected or deep discharge.

    If you monitor the voltage at the posts while charging with an old school "dumb" charger, and bounce the numbers you see off what the charts recommend you'll see they are just about perfect, they figured this shit out a hundred years ago. It's temperature dependent though, and if you forget about it and leave it hooked up you're gonna cook a battery for sure in warmer weather.
     
    Last edited: Dec 27, 2017
  25. 1oldtimer
    Joined: Aug 21, 2003
    Posts: 7,999

    1oldtimer
    ALLIANCE MEMBER

    I have a few Sun Vat 40's for battery and alt testing. Pick them up at the swap meets for $25-$30.

    [​IMG]
     
    Last edited: Dec 27, 2017
    deucemac and Blues4U like this.
  26. Truck64
    Joined: Oct 18, 2015
    Posts: 4,624

    Truck64
    Member
    from Ioway

    No, there's a shitload of 'em.... Johnson Controls, Exide, and East Penn ( Deka) are the big players here though.

    http://jgdarden.com/batteryfaq/batbrand.htm
     
  27. blazedogs
    Joined: Sep 22, 2014
    Posts: 469

    blazedogs
    Member

    Truck 64 Thank you for explaining about Battery tenders. Surprised me that no body chimed in. They're are used a lot in our cold part of the country. Was in a huge old car storage barn with many cars yesterday and they were all on tenders gene in Mn
     
    Truck64 likes this.
  28. EW_
    Joined: Apr 10, 2008
    Posts: 82

    EW_
    Member
    from DFW

    I use a SPX OTC 3165 Accuracy Plus Professional battery/charging system tester at work. It is fantastic. You enter in CCA and run a test with vehicle off. Then, start car and hold rpm above 1500 for 10 seconds. It then tells voltage, charging voltage, CCA, and if the charging system is good or bad and if you should replace the battery or charge and retest. When a battery is new, the CCA will test higher than what is printed. When the test shows the CCA significantly lower than what is printed, the battery is on the way out.
    A 12V battery at 12.2V is 50% discharged. A 12V battery at 12.5V is 20% discharged. Resting voltage should be 12.7-12.8V.
     
    BurntOutOldMechanic likes this.
  29. I’ve got an earlier version of the same tester, re branded by Mac Tools. With the accessory amp clamp for starter draw.

    [​IMG]


    Sent from my iPhone using The H.A.M.B. mobile app
     
  30. blowby
    Joined: Dec 27, 2012
    Posts: 7,514

    blowby
    Member
    from Nicasio Ca

    One other issue we're sometimes faced with, and this happened to me yesterday...One of my old heaps wouldn't start. Cranked and cranked, poured fuel down the carb, cranked, checked spark, cranked, check cap and rotor, cranked...finally hopped in another truck, had to go. No battery charger nearby. So this morning it read 12.3, and I just now got it on the charger. So, the short story is, if your car won't start and you leave it overnight with a drained battery before charging, have you done much damage? Or for that matter, if you leave the headlights on overnight and it needs a jump? Or does the sulfate process take longer?
     

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