What on-charge voltage?

[bronsonj]

2011 48v TXT.

On EZGO powerwise charger, during charge but near the end, 50.9 volts... Seems rather low.

On Aftermarket charger, during charge cycle but I assume near the end, 57.9 volts. Seems rather high so I unplugged it.

Voltage checked with ScottyB's dash mounted voltmeter and with voltmeter on aftermarket charger (both numbers matched).

Can someone tell me what max the voltage should be when charging a 48v pack?

[JohnnieB]

A 48V pack that it only being charged to an On-Charge voltage of 50.9V is being undercharged. After sitting for 12 hours, the At-Rest voltage for 100% SoC of a 48V pack of Trojan brand batteries averages 50.93V and for US Battery brand batteries the average is 51.19V. The other brands are either clones of those two brands, or fall somewhere in between.

Attached is a charger voltage setting chart from Trojan Battery.

[bronsonj]

Thanks Johnnie B!

From the attachment you had that means I should see 64.8v for a Finish Charge on a 48v pack. So my second charger when it was at 57.9v that was well in the safe range and I need to leave it plugged in.

Much appreciated sir!

[JohnnieB]

Originally Posted by bronsonj

Thanks Johnnie B!

1. From the attachment you had that means I should see 64.8v for a Finish Charge on a 48v pack.

2. So my second charger when it was at 57.9v that was well in the safe range and I need to leave it plugged in.

Much appreciated sir!

1. Not necessarily. The chart is actually the recommended charger settings for chargers that have user settable voltages. The chargers we typically use have the charging parameters loaded into them at the factory. With some of the chargers typically used with golf carts, the user can select battery brands and types.

2. Yes. The max recommended on-charge voltage for Trojan batteries is 2.79VPC (Volts per Cell), which is 66.96V for a 48V pack. However, the max on-charge reached depends on the type charger used.

The legacy chargers (ferroresonant transformer type) typically shutoff at about 2.5VPC or 60.0V for a 48V pack.

The more modern chargers using dV/dT (Change in Voltage over change in Time) technology don't shutoff until the the rate of change of the on-charge voltage slows to something like 0.004V per cell per hour. The finish voltage can reach into the mid-60V range with this type charger.