The Stovebolt Site Forums The Shop Area The Tool Chest battery tester question

I see load type battery testers for sale cheap these days. I'm curious as to how they actually put an adequate load on the battery to test it. I can't imagine that they have a built in load that draws 100 or 200 amps during the test. So, I'm thinking that they have some other method of creating an adequate load. Can one of you educate me on this please?

Mike, Your question about battery testers best fits into our Tool Chest forum, so it's been moved there for further discussion and help.

Mike, the load necessary on battery is higher than your numbers. Generally the industry standard test is:
Apply a load equal to ½ the CCA rating for 15 seconds. The voltage should stabilize above 9.6 volts while on load.
To apply a more determined test, you may apply a load equal to 100% of the rated CCA. The voltage should stabilize above 7.2 volts while on
If below 9.6 volts (7.2 volts for the 100% CCA test), recharge and repeat the test. If below 9.6 volts (7.2 volts for the 100% CCA test) again, replace the battery.

Buy a tester that can provide high numbers. Hand held probably can't do. Not sure. I say no less than This. You can download the instructions on HF website to see how to test before you buy. How they do it is Carbon Pile. (BIG!!!! resistor).
The hand held are more of a "battery health tester".

There may be some tricky wording on the hand held. "can test up to a large CCA rated battery" But can't supply the necessary amps for a proper test. the FLAPS use these hand held and can give false readings. Some don't give readout numbers, just say good/bad. They sure don't hold the applied load for 15 seconds. That's a long time.

"Carbon Pile" load testers are the only ones worth buying. They have a big stack of carbon resistor plates several inches square, and an ACME thread screw to compress them together. The good ones will have a carbon pile capable of applying up to around 1000 amps of load to a battery, which is more than the CCA rating of anything but a heavy duty Diesel truck battery. Anything else is just wishful thinking where battery load testing is concerned. A good load tester will cost around $200.00 or a bit more- - - -it's worth it!

The price jump between 500 amp and 1K amp is pretty noticeable.

www.ebay.com/itm/164885207331?

Jerry

That's interesting to me. I'm surprised that the tester's actually have carbon resistors capable of handling that load. They surely must get pretty hot when connected for 15 seconds. My original question, I was mainly thinking about the handheld type testers. I couldn't see any answers while the site was down, and I bought a handheld unit in the meantime. Since I was a little concerned about the handheld units, I spent a little more and bought one from Schumacher, in hope that it will be better than the ones from Harbor Freight and some of the low ballers. It should be here today. I'll let you know how it works out.

Notice the circular wire grill in the picture I linked? The good ones have a built-in fan to help cool the carbon pile. Yes, they definitely get hot! That type of tester can also be used to check the full-current output of an alternator by putting a load on the battery while the engine is running at a fast idle.
Jerry

....... and will grille Hot Dogs.

Mmmmmm. Hotdogs.......

Not bun length, though. That circular grille doesn't look much more than 3 or 4 inches .... And will it work on its side??

We'd better get back on topic before *we* get barbecued by the moderator ...

About half a dozen "Lil' Smokies"!

I have a 500 amp tester that's works fine for everything I work on, from a Sonota to a Duramax w/dual battery's.