Voltage reading

[racinjason89]

Does anyone know the ACTUAL voltage reading on the factory volt gauge when it says 'empty'? I'm looking to put a digital one in, but want to be able to tell my wife what voltage to charge at.

[JohnnieB]

Since some types of the LED bar graph meters have a nasty tendency to recalibrate 100% SoC to whatever the voltage is when the are connected and some reset when the batteries are charged, about the only way to get the answer to your question about your specific meter, is to carry a DVM with you and measure the pack voltage each time it drops down a bar.

However, answering the question as to when wife, or anyone else, should charge the batteries, is easy.
If it is used, it should be put on charge afterwards.
If it is not used, it should be charged once a month, or sooner.
Practicality dictates it shouldn't be put on charge if it is going to be used again in a few hours, but it won't hurt anything if it is.

A State of Charge meter, whether it is a Bar Graph, DVM or analog type, doesn't tell you when to charge the batteries.
It tells you when to turn around and head home, or in the worst case scenario, when to stop using cart and tow it home so you don't ruin the batteries.

You should never discharge cart batteries below 50% State of Charge (36.3V), so it might be an idea to suggest that the fully charged batteries (38.2V) only be discharged to 37.5V (80% SoC) before heading to where the charger is. That will give you a 10% safety margin.

Some people attach an edited voltage chart close the their DVM dash meter.
Also, remember to let batteries rest a few minutes after driving, to get an accurate SoC voltage reading.
(The electrolyte stratifies while being discharged, so the voltage is artificially low during use and immediately after stopping)

[rwt101]

State of Charge ‐ Specific Gravity ‐ Voltage ‐ Open Circuit
Percent of
Charge
Specific
Gravity
(80F)
6v 8v 12v 24 36 42 48v 72v 120v
100% 1.277 6.37 8.49 12.73 25.48 38.22 44.59 50.96 76.44 127.40
90% 1.258 6.31 8.41 12.62 25.24 37.86 44.17 50.48 75.72 126.20
80% 1.238 6.25 8.33 12.50 25.00 37.50 43.75 50.00 75.00 125.00
70% 1.217 6.19 8.25 12.37 24.76 37.14 43.33 49.52 74.28 123.80
60% 1.195 6.12 8.16 12.24 24.48 36.72 42.84 48.96 73.44 122.40
50% 1.172 6.05 8.07 12.10 24.20 36.30 42.35 48.40 72.60 121.00
40% 1.148 5.98 7.97 11.96 23.92 35.88 41.86 47.84 71.76 119.60
30% 1.124 5.91 7.88 11.81 23.64 35.46 41.37 47.28 70.92 118.20
20% 1.098 5.83 7.77 11.66 23.32 34.98 40.81 46.64 69.96 116.60
10% 1.073 5.75 7.67 11.51 23.00 34.50 40.25 46.00 69.00 115.00

Bob T

[JohnnieB]

rwt101, this is an easier to read format.

[rwt101]

Thanks
Bob T

[racinjason89]

Thank you so much for the info! The wife will be happy to have a meter AND know when to head home! :)