High voltage reading

[layne]

I've got a 48v RXV running 4 US 12v XC Batteries.

I recently installed a digital meter and it reads 52.5v 12 hrs after charging. I tested the voltage with my hand held meter and i get the same reading.

The four batteries read:
13.2
13.2
13.1
13.0

Why would these batteries all be reading high?

[tculpepper]

I forget the technical term and reasoning but, a good battery will read high. The 12 volt is just a nice round number.

[layne]

I'm wondering then since my batteries are showing 52.5 at full charge and from the charts it should be reading 50.9 and 50% should be 48.4 so does that mean my 50% SOC would now be 49.9, 70% 51.0?

[scottyb]

Numbers given are 12 to 24 hours after the charge. The pack will continue to drop or you can drive around the block and recheck

[JohnnieB]

Originally Posted by layne

I'm wondering then since my batteries are showing 52.5 at full charge and from the charts it should be reading 50.9 and 50% should be 48.4 so does that mean my 50% SOC would now be 49.9, 70% 51.0?

That chart is for Trojan batteries and their clones. Attached is a chart sent to me by US Battery for their deep-cycle (golf cart) batteries.

Even if your "Fully" charged voltage is off the top of the chart, use the voltages listed for SoC voltages less than 100%.

The charts are based on the average voltages of numerous randomly selected batteries used for testing. New batteries have a higher 100% SoC voltage than old batteries, so I suspect the test batteries were well broken in when tested.

[layne]

Thanks JohnnieB for the chart and info, that will be a big help.