Car Battery Testing ?
- Thread starter ChrisD46
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If you have a car booster pack as soon as you place cables on poles, gives you current reading before you even activate pack to jump it.
but that's not a load test...I would always have a load test performed when I suspect a battery issue...I was able to get a car/marine type battery (in this case used for a battery back up in a sump pump) to show it was at 100% but when called upon for the battery back up (the load) it failed...
I've had my load tests done at my trusted mechanics shop and they used their wheeled out battery jump starter/battery booster/battery charger...I suspect that the few times I would ever really need a load test done on a battery that it would be better to have a shop do it as the cost for one of those devices wouldn't be worth it to me...YMMV
since that fail test, I use a Deltran Battery Tender on car batteries if they are going to sit unused for any length of time, I usually replace car batteries when the warranty is up as I feel you might be on borrowed time after that and you can use a multimeter to check the battery across the terminals (I found a video on ChrisFix youtube channel)...
Good luck with your choice
Bill
I've had my load tests done at my trusted mechanics shop and they used their wheeled out battery jump starter/battery booster/battery charger...I suspect that the few times I would ever really need a load test done on a battery that it would be better to have a shop do it as the cost for one of those devices wouldn't be worth it to me...YMMV
since that fail test, I use a Deltran Battery Tender on car batteries if they are going to sit unused for any length of time, I usually replace car batteries when the warranty is up as I feel you might be on borrowed time after that and you can use a multimeter to check the battery across the terminals (I found a video on ChrisFix youtube channel)...
Good luck with your choice
Bill
Here you go: https://www.amazon.com/OTC-3180-Battery-Load-Tester/dp/B000F5HU6C/ref=sr_1_5?crid=6DUM7RLM1YZF&keywords=battery+load+tester+12v&qid=1581859838&sprefix=Battery+load%2Caps%2C315&sr=8-5
I prefer that type. Sometimes you will get false readings with the electronic load testers as compared to the analog I linked.
I prefer that type. Sometimes you will get false readings with the electronic load testers as compared to the analog I linked.
The midtronics type testers have two separate contacts in each alligator clip. The first set powers the unit. The second set, the unit sends an AC voltage back through the battery and sees how well the battery "takes it". A battery with low internal impedance (resistance) takes it better. It's then inferred that each low-resistance cell will pass current from all the other cells easily. Tester does math to compensate for temperature and state-of-charge which makes it harder to sabotage the results for good or for bad. Battery makers accept these tests for warranty returns-- 60% of rated CCA is a warning, 50% is the replace criterion. A new battery will show over 100%, and Midtronics says not to test them. But it's good for cranky customers who then think they got an extra fresh special "ringer" that was made on a Wednesday.
A true battery load test uses a carbon pile load test to put 1/2 CCA load on the battery for 15 seconds and it end of 15 seconds you read the temperature compensated voltage then turn down load and disconnect. HF sells them and they are not that expensive. The battery should be fully charged.
I would say the Midtronics and similar products are somewhat similar in that they can check the condition of the battery but do not actually put the load on it as I described. But the battery does not need to be fully charged.
Some products just put a fixed 100 amp load, read the voltage and call it a day.
Most shops use a Midtronics type tester as no need to charge battery first.
I would say the Midtronics and similar products are somewhat similar in that they can check the condition of the battery but do not actually put the load on it as I described. But the battery does not need to be fully charged.
Some products just put a fixed 100 amp load, read the voltage and call it a day.
Most shops use a Midtronics type tester as no need to charge battery first.
you can connect a VOM to the battery. have somebody start the car from cold. If the voltage drops below 10.5 the instant the engine is cranked you need a new battery. Of course there are more sophisticated ways to perform a battery load test.
this one works for me if this one says it's bad the battery store tester shows it bad also without fail YMMV
https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html
https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html
I used to use the hand held type. Similar to what I've seen used at the auto parts stores. Turn on lights, radio, fan on high, etc. connect it to the battery, flip a switch, it somehow puts extra load on things and shows where the battery and charging system are, in terms of handling it. The thing used to get hot so my guess is it created some resistance somehow. More than once on older cars I've driven it's helped me know if the battery is the culprit or the charging system. On older batteries it also lets you know if replacing your battery preemptively is worth it. I want to say it was $50 or under.
Originally Posted by faltic
this one works for me if this one says it's bad the battery store tester shows it bad also without fail YMMV
https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html
This looks almost exactly like the one I have used. I'm pretty sure my specimen is a Craftsman brand from the 80's...
Again, I think auto parts or battery places will do a load test "free". Just make sure the person using it actually knows how to use it. Or just ask to borrow it and watch a YouTube video or something.
this one works for me if this one says it's bad the battery store tester shows it bad also without fail YMMV
https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html
This looks almost exactly like the one I have used. I'm pretty sure my specimen is a Craftsman brand from the 80's...
Again, I think auto parts or battery places will do a load test "free". Just make sure the person using it actually knows how to use it. Or just ask to borrow it and watch a YouTube video or something.
I have the HF carbon pile one, it actually works pretty good. But what I did in the poor mans day, on a fresh charged battery, was turn ignition on, but don't start car. Turn lights on to high beam, fogs on if equipped, a/c fan to hi, radio on, and cig lighter in. Then check battery voltage. Anything under 11.5 volts, the battery goes.
In absolute terms I wonder how accurate CCA testers are because in doing a load test at normal ambient temperatures they can only infer the real CCA at 0 F.
Regardless of absolute accuracy, it's a useful comparative test and load testing a new battery would establish a benchmark for further tests later in the batteries life
Regardless of absolute accuracy, it's a useful comparative test and load testing a new battery would establish a benchmark for further tests later in the batteries life
I have a Solar BA9 tester that works pretty well.
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