Battery Charger ATS-1 feature WHY?

[MoonlightVFR]

I have a new battery charger. I like to buy tools.

Battery Minder 12248-AA-S5

I am not familiar with the feature ATS-1 Ambient Temperature Sensor.
This appears to be a calibrated thermistor to regulate charger output.

But why have this feature at all? I have charged aviation battery with simple chargers for 30 years.

Page 9 of instructions currently states "ATS-1 is mandatory when used with ALL Aviation batteries" Sounds rather dogmatic doesn't it?

Can anyone enlighten our group with a TRUE benefit from the ATS-1 feature?

Regards

[Bruce Fenstermacher]

Just because you've charged aviation batteries for 30 years does not mean that you have charged aviation batteries in the best possible manner for 30 years.

We now have readily available relatively cheap technology to allow us to do a better job. In many cases this is splitting hairs we could never split before.

My guess would be that the thermistor calibrates the rest of the charging circuit to hold those electronics to a tighter tolerance and repeatability allowing for a more consistent performance no matter the temperature.

When batteries were cheap and their components not considered hazardous, we didn't care to get the max performance and longest life from them. We just bought another one. Times have changed.

[DaveF]

The optimal charge voltage depends strongly on temperature. Every voltage regulator designed since 1960 has a temperature sensor. Here's Gill's recommended charge voltage vs. temperature.

BatteryChargeVoltagesGill.JPG