Quote:
Originally Posted by ajbrown
50% state of charge is an indicator of how much energy is left in the battery for this charge cycle, i.e., how many holes it will go. It is not an indicator that it has 50% useful life left. In fact a battery that can only be charged to 50% SOC is likely nearing end of life. IMO that is very low.
Here is a graph I did some time ago in which I tracked the pack voltage for two separate rides. All packs will have their own line if you were to chart them during usage as I did. The cart charted below had a good pack and could go quite far as it has 8-6v batteries.
Based on my chart the cart looks like it could theoretically go about 75-80 miles before causing great harm to the pack. Now look at the same line but start at 50% SOC. Looks like I could go 32-35 miles if I started with an SOC of 50%.
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So, as indicated in my last post, it is all about what is considered 50%, or 20%, or discharged.
For a 48-volt system, some references show 20% State of Charge to be 48 volts; yours 46.62; another 46.32. Trojan has it at 46.64. E Z Go & US Battery has it at 47.92.
Well, it can't be all of them.
I checked a cart with brand new batteries, with a full charge, and it was 12.79, 12.80, 12.74 & 12.79 = 51.12.
When I check carts we are having problems with, dying on the first 18, I get readings like 12.1 on one battery. According to your graph, four batteries reading 12.1 are at 50%, so the cart would likely be dying on the course fairly quickly.
I went out to exchange one cart, and the guy in the foursome behind that one thought we came for his! The guy following me to push me back in gave his cart to the other guy. So, neither of us made it back in. Those two carts each had readings of 12.3 in 3 batteries, and 6.3 in the fourth. That would be 43.2, and they were still limping along on level ground.
Regardless, we should not be having these problems with one-year-old, top-of-the-line carts.
I'm doing my best to draw conclusions, and report to my higher-ups, with an inexact science.