Conductance Battery Testers

Anyone know if the conductance type (not load type) battery testers are useful with Marine/RV deep cycle batteries?

Well aware that these testers are notorious for false "Good" readings but do not know it they are even useful with deep cycle batteries.

Dean

Dean,
I have no knowledge of those conduction type testers that you asked about, but here are some things to think about that usually need to be done while diagnosing, wether it is electrical or mechanical.

In order to diagnose, first try to test the component under it's intented operating condition. Not always possible, many things affect the duplicating process.

How many times a dealer of repair shop states: could not duplicate. So the problem is still there.

Successful testing of a battery is achieved then when the battery is tested as it's intended use conditions.
Cranking; amp hours;, stand by voltage loss.

Just a few thoughts,

Guido.

Not an expert on the subject, but I have used one of these testers on deep cycle batteries and the results seemed to be accurate. By the way, I find these testers to be very useful. Yes, there can be a battery that tests good, but fails under load. I find in most cases these testers can give you a good idea of battery condition and if used somewhat regularly, can prevent you from incurring a total failure at a bad time.

These testers are effective, and often times will condemn batteries before they leave you stranded. They are usually small, handheld and easy to use. I sometimes think they are too sensitive, meaning they will fail a battery long before you notice it's weak. This is a good thing to keep you from being stranded but a weak battery could last another year too. I don't know of a single OEM dealer, or battery place that doesn't use this type of tester for their own warranty purposes, this means they have a strong belief in this type of tester and not the others.

Actually it's the other way around.

If a decent conductance type battery tester indicates that a fully charged battery being tested is "bad" it almost certainly is.

On the other hand, such testers are notorious for false "Good" readings.

Of course, the only reliable way to test such batteries is with a load tester but I do not have one.

Dean

Thanks, Guido, and I agree.

The battery in question is a six year old 24DC deep cycle battery on a gate opener 900' from a power source.

I'm confident that it has failed and ordered a new one yesterday after posting above. In the meantime, I'm experimenting with the old one.

I have no load tester so planned to charge the old one on one of my maintainers and have it tested by the conductance type tester at the place where I am buying the new battery. However, after 24 hours, the maintainer is still indicating "Charging". The maintainer charges at a 1 A rate, so if the battery was going to take a charge, it should have done so by now.

Thinking about shocking it at 30 amps or so with one of my HD chargers to see what happens but any recovery would be only temporary.

Dean

Its not a belief its any dummy can program the info the tester does the work. Load testing is still the gold standard but it takes knowledge to perform the test plus quality load testers are expensive.

The advantage of a conductance tester is it cuts warranty issues at least 50% and I would wager more.

Dean I dunno I don't have any faith in a conductance test other than to say I load test them like any other battery. 200 amps for 15 seconds will give you a ID of where the battery stands. Install it in a tractor etc crank it for 10/15 sec. record the voltage is about as simple a test as I can think of.

I run across several quality load testers a year other than the one I brought new the most I have paid for them is $40 : ) I am blessed with them at this time. The last one I brought a Sun Vat 40 the shop owner said his mechanic did not trust it neither he are his help knew what they were doing. The screw that retained the load knob was loose : ) you could not crank the load down enoufh. The analog voltmeter is off a tad I always hook up a DVOM anyways its no big deal. The amp function is dead nuts are close enoufh to get the idea.

The ability to quickly move the amp clamp to the alternator/starter is priceless...

I have used them on both types of batteries with good luck. There could be a mechanical crack that can heat up under higher current that these testers can NOT detect. AS others have said, when they show bad, they are accurate. When they show good, they are mostly accurate.

I also have a recondition feature on my better chargers.. I can watch a battery slowly over time loose capacity with these meters. I can run a 48 hour "recondition" cycle and see the capacity come back as the sulfate on the plates is dissolved, meaning more amperage is now available. Retesting shows usually the improvement, but sometimes the sulfate has harden and the capacity can not be improved.

I dont use agm batteries so I can not comment on those. Every time I tired an agm, they failed early, so no agms batteries used at StickerCreek Ranch.

Dean,

A volt meter is what i use. Check voltages at different stage of charging, can't stress that enough! A good battery will get up to voltage GRADUALLY. While a bad battery will shoot up to 14 volts within minutes into charging it.

Also check the top of the battery for voltage leak between the + post and the top. In your application is more important in then automotive application.

Do that to the new one too. A bit of soda carbonated or powder will do. Wet and rinse.

If its open top check the cells level,


Guido.

So that begs the question: What kind of a rigged tester does Walmart use to cheat people into not having to replace their battery?

(quoted from post at 10:25:07 01/10/21) Actually it's the other way around.

If a decent conductance type battery tester indicates that a fully charged battery being tested is "bad" it almost certainly is.

On the other hand, such testers are notorious for false "Good" readings.

Of course, the only reliable way to test such batteries is with a load tester but I do not have one.

Dean

Click to expand...

have a Harbor Freight load tester that I bought for around $20. I believe it works, but am still treating with a certain amount of skepticism.

Do I detect a bit of paranoia?

Dean

(quoted from post at 14:20:55 01/10/21)

(quoted from post at 10:25:07 01/10/21) Actually it's the other way around.

If a decent conductance type battery tester indicates that a fully charged battery being tested is "bad" it almost certainly is.

On the other hand, such testers are notorious for false "Good" readings.

Of course, the only reliable way to test such batteries is with a load tester but I do not have one.

Dean

Click to expand...

have a Harbor Freight load tester that I bought for around $20. I believe it works, but am still treating with a certain amount of skepticism.

Click to expand...

Skepticism" well placed, as I have the HF unit which provides only a tiny 17 ampere load, whereas my real load tester provides for 400 amperes.