Golf cart battery history chart

[Babyboomerboy]

I guess I have too much time on my hands but after I bought the new batteries and JohnnieB suggested I number them so I could keep track of each, I decided to start a chart the first of the year. I have charged and discharged the new batteries several times before this chart began Jan 4th. I am not sure if this will tell you anything but you can see just what JohnnieB and some of the others are saying about the dropping amps when charging and the slow drain from sitting. This chart was done in Kansas in the winter, inside a sometimes heated garage. Sometimes meaning when I get cold I start a fire in the stove. If you can see anything from this chart that I should be aware of please let me know. Thanks

[ArmyVetSgtAdkins]

And I thought I was only one who charted things like this

[Babyboomerboy]

Originally Posted by ArmyVetSgtAdkins

And I thought I was only one who charted things like this

You sayin' not everybody does this?

[subby44]

ummmmm. I am not one of those guys

Could you tell me why you are doing that? I might be one of those guys if it makes sense to me!!!

[JohnnieB]

Charge rate and times seem to be about normal. (About 4 hours from about 85%SoC)

Battery pack discharges about 1% per day while sitting, so 30 days (70% SoC) is the max you want to let the cart sit without recharging.
Note: This discharge rate is the self-discharge of the batteries, Plus any other drain on them. (IE: The controller draws up to about 0.020A through the Pre-charge resistor to keep the filter capacitors charged, so the solenoid contacts don't arc as much when they close.)

If you use the headlights often, it would be a good idea to install a 36V to 12V converter or a separate 12V battery, so you don't ruin batteries 3 and 4 by taping them for the 12V to run the headlights.

As an alternative, Give batteries 3 & 4 a boost charge with a 12V charger whenever they fall more than 0.1V lower than the rest of the pack.

-----------
Just curious.
What batteries and charger do you have?

My Exide GC-145 (245AH) batteries self-discharge at a bit over 0.5% per day. (Down to 90%SoC after 19 days of sitting, connected together, but not connected to anything)

[JohnnieB]

Originally Posted by subby44

ummmmm. I am not one of those guys

Could you tell me why you are doing that? I might be one of those guys if it makes sense to me!!!

It establishes a base line for later comparisons, and by jotting down various readings and when they were taken, you might spot something going bad and have an opportunity to address the issue before you get stranded in the middle of nowhere.

For example: On 2/5, our baby-boomer friend played 9 holes, plus 1/2 mile drive and went from about 98%SoC down to about 83%SoC, or about 15% of his battery pack's storage capacity.
If he does the same a year on so down the road, he will be able to tell how well his battery maintenance program is working by the increase in how much storage capacity is needed to make about the same trip. If it is just a few percentage points, it is the natural aging of the batteries than cannot be avoided, but if it doubles, it is time for him to rethink his battery maintenance program.

It doesn't have to be elaborate or every time you charge, just whenever you are under the seat to clean and water.
If you want to track run-time, Just jot down the pack voltage before and after you drive a specific route a couple times a year.

[cableguy_hd]

WOW, I got something to look forward to when I retire... in 25 years I hope But I did enjoy reading your chart tho... Wish I had time to do that now