Projected life expectancy of battery (JohnnieB)

[JohnnieB]

FWIW: I just put together a chart for 6V batteries that compares relative Lifespan projections based on Amp-Hours.

As you can see from the graph I posted earlier, showing projected charge cycles based on average SoC maintained, each battery manufacture come up with different numbers, so I used the average of the three sets of numbers I have (Exide, Trojan and US Battery) for Average SoC vs Charger cycles.

I used 225AH as the Standard golf cart battery and discharged all of the batteries by 430Watt-Hours, which is approximately a discharge to 70% SoC for a 225AH battery.

The life expectancy is based on a daily discharge by 430Wh (Roughly 67.6AH) and a daily recharge to 100% SoC. Other factors influence life expectancy, so the months and years given will vary accordingly, but if those factors remain consistent, the % Gain or Loss from the standard battery will hold true.

To find the best bang for the buck, divide the total cost to get the batteries sitting in your cart by the months of lifespan for the battery's AH rating.

Of course, desired run-time and cart performance have to be taken into consideration as well as cost.

[yurtle]

Originally Posted by JohnnieB

I used to be a teacher, so I'll have to track you down and give you a couple raps across the knuckles if you stop reading the forum.

I have an old-school ruler you can use. You can't borrow my bamboo slide ruler though.

[beachin]

Originally Posted by JohnnieB

The life expectancy is based on a daily discharge by 430Wh (Roughly 67.6AH) and a daily recharge to 100% SoC. Other factors influence life expectancy, so the months and years given will vary accordingly, but if those factors remain consistent, the % Gain or Loss from the standard battery will hold true.

If the discharge is changed from daily to either weekly or bi-weekly, how much might that use pattern skew the projections?

[JohnnieB]

Originally Posted by beachin

If the discharge is changed from daily to either weekly or bi-weekly, how much might that use pattern skew the projections?

The projected number of cycle is based on the overall average SoC, and the batteries sitting in a partially discharged state will lower the overall average, so the number of cycles available will be reduced. That means there are two conflicting timelines.

Granted, lengthening the time between charge cycle trends towards lengthening the lifespan, however lengthening the amount of time the batteries sit partially discharged trends towards reducing the number of cycles available, shortening the lifespan. Theoretically, the charging practice that gives the greatest lifespan would be where those two timelines intersect, but wherever that point is, the higher AH battery will have the longer lifespan if the same charging practice is used.

Something that also has to be taken into consideration is depth of discharge. The depth of discharge vs number of charge cycles used, isn't a linear progression. As I understand it, playing a round of golf and then recharging, uses 1 charge cycle, however playing two rounds of golf before recharging uses 3 charge cycles. That means if you played a round of golf every day, but only charged every other day, you would be using 21 cycle per fortnight instead of 14, so you'd be loosing lifespan rather than gaining it.

Personally, I believe the best overall charging practice is to recharge the batteries as soon as possible and practical after use and float charge the batteries between uses.

[theskyiscrying]

Thanks everyone for the input, makes lots of sense.
A special thanks to JohnnieB for the technical knowledge.

[eflyguy]

Might be appropriate to ask this question here:

If I'm driving the cart around the house and only pulling, say, 5% of the charge out, is it better to recharge or not?

Is it also better to wait for the batteries to "recover" after use, before plugging in? Thinking voltage climbs slowly after a heavy load, which means they look like they are lower than they really are right after use.

I'm trusting that the smart charger will figure it out..
..a

[rsw007]

Originally Posted by eflyguy

Might be appropriate to ask this question here:

If I'm driving the cart around the house and only pulling, say, 5% of the charge out, is it better to recharge or not?

Is it also better to wait for the batteries to "recover" after use, before plugging in? Thinking voltage climbs slowly after a heavy load, which means they look like they are lower than they really are right after use.

I'm trusting that the smart charger will figure it out..
..a

good question I would like to k ow as well. also do they need to rest before using the cart. or can u use it when its up around 4o+ volts off the charger.

[yurtle]

Always recharge.

[rsw007]

after break in can u charge for hour then use cart ? or should u always let it finish charging before use? we use ours in the morning and few hours later at lunch then again at dark. we have just been charging at night because it takes several hours to charge even if its still above 38v.

[yurtle]

Any charge is better than none. I often use in the morning then plug in before later use. Even if it doesn't get a full charge, every bit helps.

By charging (even if not fully) you prevent the batteries from getting as low as they might otherwise get. Low SOC, and keeping it low for prolonged time, lowers the battery's life.