Adjusting charger voltage for temperature variation (lead acid batteries)

[Daox]

I've been to this website before, but never really read through a lot of it. I came across this nugget this morning though. Something potentially useful for a lot of us now that we'll be seeing some colder weather.

Charging the lead-acid battery - batteryuniversity.com

Correct settings of the voltage limits are critical and range from 2.30V to 2.45V. Setting the voltage limit is a compromise. On one end, the battery wants to be fully charged to get maximum capacity and avoid sulfation on the negative plate. A continually over-saturated condition at the other end, however, would cause grid corrosion on the positive plate. It also promotes gassing, which results in venting and loss of electrolyte.

The voltage limit shifts with temperature. A higher temperature requires slightly lower voltages and vice versa. Chargers that are exposed to large temperature fluctuations should be equipped with temperature sensors to to adjust the charge voltage for optimum charge. Figure 2 compares the advantages and limitations of various peak voltage settings.

For example, I believe my Schumacher 12V charger charges my Paseo battery at 14.5V. In summer I may want that to be lowered to lengthen battery life. However, in winter, it sounds like I should kick it up a little to give me a little extra capacity. I'm honestly not sure that the Schumacher has a temp sensor, or even adjustable voltage though. If you have an EV, I'd imagine this is much more important though.

[MetroMPG]

I'm not sure if my charger regulates voltage thresholds based on ambient temperature.

The only temp related function I know it has for sure is charger related: if the charger internals get too hot, it stops or reduces output until it cools down.

[bennelson]

According to the manual of my K&W BC-20 charger, it does have built-in temperature compensation.

The charger and batteries should be at the same temperature for it to work properly. The charger is mounted in the car, only a few feet from the batteries, so I don't see it as a problem.

I may start doing some checks with a volt-meter and see how my resting charged voltages are compared to that chart.