Parallax Power Supply 7345

bigfootford wrote:
I disagree with measuring the ambient air temp around the battery.
It makes no sense.

Please provide your source for this statement.

The source for this statement is the dozens of battery tables we've all seen of terminal voltages and/or charging voltages of lead acid batteries versus degrees Fahrenheit. All tables like this I've seen have never mentioned the temperature of the electrolyte or the temperature of the battery's terminals or case. Of course attaching the probe to the terminals or the case is convenient, but is going to be some kind of average of the temperature of the battery's mass versus the air around the case in the immediate area where the case-air heat transfer is taking place. I guess I've always assumed that the table temperatures meant the temperatures of the air in the immediate vicinity of the battery (i.e. the temperature of where one was camping) - hence my talking about a probe from a temperature compensating charger being placed very close to the battery(ies) right in the compartment where you have them.

Here's a typical writeup for us laymen that talks about the charging voltages applied to lead acid batteries depending upon some kind of temperature ... it sure reads like they're talking about the temperature of the environment that the battery is in:

http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures