What are the correct voltages for a 48v charger to go up to before it cuts off?

[scottyb]

Most simple chargers works in phases. The final phase is equalization which is the lowest amperage and it is also the longest phase.

[Jeffreynmandy]

Here's a section on Trojans website about equalizing. I assume this is what the charger is doing. Trojan recommends 62v for equalizing.


-----------------Trojan website---------------------------------------------------------


Equalizing is an overcharge performed on flooded lead acid batteries after they have been fully charged.

It reverses the buildup of negative chemical effects like stratification, a condition where acid concentration is greater at the bottom of the battery than at the top. Equalizing also helps to remove sulfate crystals that might have built up on the plates. If left unchecked, this condition, called sulfation, will reduce the overall capacity of the battery.

Many experts recommend that batteries be equalized periodically, ranging anywhere from once a month to once or twice per year. However, Trojan only recommends equalizing when low or wide ranging specific gravity (+/- .015) are detected after fully charging a battery.


Step-By-Step Equalizing

Verify the battery(s) are flooded type.
Remove all loads from the batteries.
Connect battery charger.
Set charger for the equalizing voltage (See Table 2 in the Charging section). If your charger doesn’t have an equalization mode, you can unplug the charger and re-plug it back in. This also will conduct the equalization charge.
Start charging batteries.
Batteries will begin gassing and bubbling vigorously.
Take specific gravity readings every hour.
Equalization is complete when specific gravity values no longer rise during the gassing stage.

[JohnnieB]

To answer the question asked in the thread title: It depends on the charger.

Technically, a battery is not fully charged until the specific gravity of the electrolyte ceases to rise while there is a charging current passing through it.

Since the voltage tracks the the specific gravity, it can be inferred that the battery is not fully charged until the voltage ceases to rise while a charging current is passing through the electrolyte.

Since the batteries are charged in series, older designs of chargers used a pre-selected voltage to terminate the charge at a point that nearly fully charged healthy battery cells without significantly overcharging the less healthy ones. 48V chargers of this design typically shutoff in the 59V to 63V range.

More recent charger designs use what is known as dV/dT (change in Voltage over change in Time) and when the on-charge voltage for the battery pack stops climbing (actually rises slower than a pre-selected number of millivolts of s pre-selected period of time), the charge is terminated. Since the on-charge voltage is not limited to the low 60's, it can climb up to about 67V or 68V before the charge terminates. Some chargers using dV/dT technology don't allow the voltage to exceed some pre-selected maximum and nearly all have safety timers that terminates the charge if the charge is not terminated by the dV/dT process within a pre-selected number of hours.

I'm pretty sure the Eagle Pro chargers use dV/dT technology, so the on-charge voltage can get into the high 60's and the safety timer they use is about 20 hours.

[Jeffreynmandy]

I finally got a chance to let it run until cutoff. It must go into maintenance mode right at 64v.


I wouldn't have thought it would need to go that high, I guess I learn something new everyday.

[cgtech]

I think that voltage is just a little high for trojans to see on a regular basis, keep an eye on the peak voltages while they are on their extended charges in the future. Star car used those "eagles" from the factory, and they charged those 8x 6v trojans too high, too long (i have a sheet from "eagle" that shows 32 hours on charge is "OK" before cutting off during "maintenance mode" lights 1 & 5 flashing ?!?!). The batteries all had Positive terminals protruding upward from their original location at the end of their life, sometimes enough to cause small cracks in the lid of the battery. In that Star situation, Star always said "send it to Eagle for reprogramming", Eagle always said "Star specified their charge profile, not our fault" - "Who-dunn-it" BS! One thing i will give Eagle/Procharge, i saw a very low "outright failure/charger is inoperable".

[Jeffreynmandy]

If I run across a better one at a good price I'll probably get it. Is it best to stick with this one for now, or would a factory Ezgo 48v be better?

Maybe it was doing a equalize charge. Hopefully it'll kick off a little sooner next time but I doubt it. I drove to probably 50-60% charge, and it took about 7 hrs to recharge.


I can't complain though, I bought the motor, controller, cables, solenoid, 2 chargers, seat, and 2 hubs for the price of just the charger

[cgtech]

Factory QE charger? (small with many fins). If the voltages dont "settle down", i might suggest using it instead ('till it croaks).

[Jeffreynmandy]

I went to charge my batteries again. I don't know how long it was, only 2-3 hours at most. I plugged it in and went to town.

I was expecting another 7-8 hour charge, but went I got home it was turned off. The voltage was 50.4


Maybe the last charge was an equalization charge hopefully.


Does a 2-3hr charge sound right if the batteries were around 60-70%?

[cgtech]

That seems a little short (i would expect about 5hr, the last 20% to top off the batteries takes the longest to do) . Are you sure about the SOC when you plugged it in?

[Jeffreynmandy]

I'm a little puzzled by it also. I can't say for sure. when I get a chance I'll drive it a few miles and stay home to watch it.


50.4 is a good number though right?