Battery Life

[Sarge50]

I'm sure this has been asked before, Will Batteries last longer if charged at 50% SOC or is it calander based. Example new batteries will last how long If you take care of your batteries and always charge before 50% SOC how long can you expect them to last? Is it a calendar based or charge based? Example, new Batteries will last 2000 charges at 75% SOC verses new Batts wiil last 1000 charges at 50 % SOC or Batts will last 4 years etc?

[sportcoupe]

The life expectancy dramatically decreases if you discharge past 50% SOC. Life is measured in cycles which is one charge and discharge. See chart.

[JohnnieB]

It is next to impossible to quantify how long cart batteries will last because there are so many variables that influence their usable lifespan and we don't have control over all of the factors.

For example, FLA (Flooded Lead-Acid) batteries have a longer useable lifespan in cold climates than they do in hot climates, but we don't have much control over the climate. See attached chart.

However, as shown on the chart sportcoupe posted, the average SoC (State of Charge) maintained is a major factor and we do have control over how deeply we discharge our batteries and when we recharge them.

Basically, cart batteries ought to be recharged after each use, no matter how slight the use, or how often the cart is used. (The how often part gets a little tricky because FLA batteries self-discharge.)

If you use the cart to make several short trips during the day, putting on charge that night is sufficient as long as the SoC does not taken below 50%. The import thing is not letting the batteries sit overnight in a partially discharged state and anything less than 100% SoC is partially discharged.

Since FLA batteries do self-discharge, the SoC drops below 100% soon after the charger shuts off, so float charging is needed to keep them at 100% SoC.

As for controlling how deeply the batteries are discharged, that starts when the AH capacity of the batteries to be purchased is being chosen.
With all other factors being equal, a higher AH battery will last longer than a lower AH battery because the SoC at the end of the same trip, in the same cart, over the same terrain, at the same speeds, by the same driver and number of passengers, of the lower AH battery will be lower simply because there were fewer AH stored at the beginning of the trip.

The second attachment shows the projected increase or decrease in lifespan of 6V batteries based on AH capacity. The baseline is a 225AH battery being discharged to 70% SoC daily, and recharged daily.

Bottom line: For maximum useable lifespan, buy the highest AH you can afford, get a charger that float charges after the regular charge cycle terminates and have charger plugged into cart when cart is not being driven.

[Sarge50]

Very good answers guys!!! Thanks for your help. I will head your advice.