Battery Discharge Rate

[e-z-go1988]

I monitored my battery pack voltage for 1 week and the total voltage drop for that week was 0.07v or 0.01v per day. At the 0.07v/week rate (if constant) it would take approximately 14 weeks of not using the cart to reduce the battery pack voltage to 37.49v (80%). I had expected a greater voltage loss.
I have 3 year old T105 batteries in the cart. The fully charged pack when I started monitoring was 38.53v and after 1 week 38.46v.
Have a good day.

[scottyb]

Surface voltage readings are deceptive. Take the same cart and drive it up a hill for say 1-5 minutes and then retake your readings ~ you might be surprised...
FYI
Trojan Batteries says the pack will loose 4% of it's total charge each week sitting idle.
4% of 38.4 = 1.5v

[e-z-go1988]

Originally Posted by scottyb

Surface voltage readings are deceptive. Take the same cart and drive it up a hill for say 1-5 minutes and then retake your readings ~ you might be surprised...
FYI
Trojan Batteries says the pack will loose 4% of it's total charge each week sitting idle.
4% of 38.4 = 1.5v

My test showed that my fully charged batteries "setting idol for a week" do not show the 4% discharge rate advertised by Trojan, which is not a bad thing!
What test parameters do you suggest I use to confirm Trojan's 4% discharge rate? Should I run the batteries down to 90% then measure and record voltage and wait a week and measure voltage then I will see the 4% voltage drop?
Reason for the test was to determine what level of trickle charge I needed to supply during the winter when I use the cart infrequently, just to keep the batteries in fully charged condition. My test shows me that the rate of discharge is minimal, however I will still use the 36v trickle charger, once I have fully charged the batteries with the main 20A charger.
Thanks again for the input.