https://marinehowto.com/are-battery-conductance-testers-worth-it/
So how can you use one if you already bought it? I still suspect we can draw some conclusions from an initial baseline to a future test using the same tester and the same batteries. I have developed lots of these sorts of data-sets for our Argus and Midtronics testers, but they keep proving us wrong and this is very, very frustrating. IF we figure out a translation and think we nailed it we get thrown a curve ball on the next battery.
- If you want to know the cranking ability of a battery, the Midtronics testers can be useful.
- If you want to know your batteries SoH, as related to Ah capacity, fogedaboutit.
The bottom line is that impedance/conductance testers simply do not translate to SoH for usable Ah capacity. For deep-cycle house banks Ah capacity or usable Ah capacity is all that matters. I certainly wish they were more accurate because it would make our life much, much easier.
I have no qualms with the Midtronics tool for predicting cranking capacity, and suspect it is rather accurate. If buying a conductance tester, for cranking testing, the only one we recommend is the Midtronics line or a company that licenses with Midtronics for its technology.
The slew of Chinese testers out there are pure unadulterated crap. We have now tested about 8 different Chinese testers and not a single one comes anywhere close to the Midtronics. The Harbor Freight / Centech is not worth the cardboard box it ships in. Garbage data is garbage data.