Equalizing Batteries

mark74star

Greetings from Northern Ohio,

Hey guys, I love this site!

I'm interested to see how many of you "equalize" golf cart batteries? We maintain 72 RXV carts and the battery discharge times are suspect. The batteries have less than a year on them, so we've expected better results.

Does equalizing always improve battery life? (if done correctly)

Can it hurt a set of batteries at all?

Some battery companies recommend doing this once a month, and i have never done this, maybe i should be....

Thank you all for any input on this matter!

BGW

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

scottyb

Deep discharging will cut the number of times a set can be brought back to full charge. An equalizing charge is as easy to do as back to back charging. It definitely helps keep the batteries healthy. Below is from Trojan Battery Co.

Equalizing
FLOODED BATTERIES ONLY

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

Are the battery packs becoming unbalanced? (At-Rest voltage between 12V batteries varying more than 0.2V)

That is the typical indicator the equalization is needed.

Or is it just short run-time issues?

mark74star

JohnnieB,

I'm mainly concerned about poor discharge times, and why we are getting them on batteries with approximately 150 hours on them. We have 2015 RXV's with US Battery 12V XC's in them. The batteries read on the case as 77 mins @75 amps, 292 mins @25 amps. i assume 77 mins is my max discharge time....

A couple examples of what we are seeing:

Cart A---discharge time of 66 mins, voltages taken after DC
11.36-11.39-11.24
11.37 TV-45.5
Cart B---discharge time of 40 mins,
11.83-11.73-11.28
11.84 TV-46.7

A couple of variables may include battery and motor temperatures. I try to leave them in heated storage for a couple of days to warm up to around 60F, for a more efficient charge/discharge cycle.

Scotty, thanks for the info on equalizing. If it helps the longevity of our batteries we will implement the practice on carts that may need it.

Thanks to all as I'd like to know as much as possible on these things...

Sergio

Your test for run times may not be a match for the manufacturer ratings.

The manufacturer battery ratings for run time are measured at 80F and until the Volts per cell is down to 1.75v.

That would translate to a battery final voltage of 10.5v @ 80F.

I also noticed that both sets have one battery that is much lower, do You have any accessories tapping a single 12v battery?

JohnnieB

For the most part, the care and feeding of US Battery batteries is the same as it is for Trojan batteries, but there are some differences in State of Charge vs Voltage and the specific gravity of the electrolyte used, so I've attached the spec sheet for US 12V XC2 batteries (2015 revision)

I suspect your load tester is discharging at 56A when set to 12V batteries, so the minutes at 80° is 110. If they are being load tested at 60°F, then the minutes would be 95.7, which is 87.5% of 110.

If the cart's average amp draw is 56A, the run-time to 50% SoC is only 48 Minutes at 60°F and less if the batteries are colder. (There is a battery temperature vs storage capacity chart in the attached specs.)

Also the spec sheet recommends monthly equalization for actively used batteries.

-------------
Note: Not all chargers fully charge US Battery batteries, so check with USB to verify the chargers being used are compatible with US Battery charging specs.

FWIW: Since you have 288 US 12V XC2's in use, I suspect US Battery will provide you with all the information you want, and then some.

Attached Files

usb_12V_data_sheet_2015_web(1).pdf (672.3 KB, 0 views)