Ah meter?

[JohnnieB]

Originally Posted by sleepyluke

Thanks for the breakdown. So I know it is personal choice, but when do you know it is time to replace batteries, when it really drops off in the cold, seemingly more than the chart calculations say it should? Or whole mother topic?! I am losing more run time than calculated but I have 4 year old batts that I have no clue how well they were treated until a year ago when I got it.

Thanks again for helping the dummy! this may be why I have always owned gas carts till now......but I am loving the learning and the challenges of electrics.

I got my 2008 cart in 2011 after it came off a 3yr lease from a golf course in Arizona and it had a set of "L9" date coded batteries (Dec-09) in it and they would only charge to 85% SoC, so the cart guys at the course probably would have soon been putting in a third set of batteries if the had kept the cart.

It is very likely that 4 year old batteries with an uncertain maintenance history have reached the end of their useful life.

When to replace batteries? When the cart's performance and/or run-time are no longer acceptable to you.
Like you said, it is a personal choice.

My guess is that due to age alone, your batteries have less half of their rated AH capacity, so cold weather takes a really big bite out of what little capacity they have left.

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Run-time is tied to AH capacity is measured by discharging the battery at a constant amp rate and measuring the number of minutes it takes for the voltage to drop to 1.75VPC. This process is called load testing. (Other types of load-testing are also done, but this is the yardstick used for rating cart batteries)

A T-105 is rated for 115 minutes at 80°F with 75A discharge rate. When the minutes drop to about have the rated number, it is time to start looking for replacement batteries.

[yurtle]

Originally Posted by JohnnieB

A cold battery already has a reduced storage capacity, so I'm not sure if using more energy from it would be a good idea or not.
Maybe an auxiliary battery or two stashed in the bagwell could be used instead of the main pack.

I've never checked to see how much heating float charging generates, or discharge does. Looks like my To-Do list got longer.

My thought was that the heater would always be on, and propped up by the float charger. The load would have to be low enough so that the charger would be happy "floating" the batteries and the heater. Once you leave and start running, the heater could turn off at a set SOC.