New batteries, low voltage

[jdunmyer]

My cart is a 2013 RXV, bought new, came with a charger (QE?), plus I bought an Accu-Sense unit. Original batteries were about used up, so...

Not wanting to handle those heavy batteries, I took the cart to an EZ-Go dealer, not the one I bought it from, as he is 250 miles away. Got it back the next day, and the DVM on the dash (from ScottyB) showed 'low', and the OEM 'fuel gauge' also showed 'not full'. Charged it with the QE charger, went to use it a couple of days later and found the voltage 'low' again, something like 50.0 volts.

Charged it with the A-S unit, only to find the voltage 'low' the next day. Checked the batteries and found them to be about 12.25 volts, +/- about .03 volts.

Did some brief checks and found that the charger pushes the voltage to 57 or more, then shuts off after a short while. Within an hour or 2, the voltage has dropped to 50.0.

These are brand-new Crown batteries.

What gives?

[handtools]

What do they settle at 12 hours off the charger? New batteries usually take awhile to break in and get up to full capacity. It's cold in Michigan and that will affect how they charge also. I would just keep charging them.

[JohnnieB]

If by "Accu-Sense unit" you mean a DPI Accu-Sense charger (probably a Gen IV), use it instead of the PW-QE P.O.S.

Attachment-1 is a SoC chart for Crown golf cart batteries. (lower voltages than Trojan or US Battery)

A new battery only has about 75% of its rated storage capacity (AH) until it has been broken in, which may take 50 or more charge cycles.

So your 12V-155AH batteries only had about 116AH when first installed and a Deep-Cycle Lead-Acid loses about 10% of its storage capacity for every 15°F below 80°, the temperature cart batteries are rated at. I used to live in SE MI (South Lyon) so I know it is a bit chilly this time of the year.

However, the SoC voltage ought to be about what the chart says no matter how low the storage capacity is, so the PW-QE might not be working right. Try the DPI and see what you get.

[jdunmyer]

Hmmm... The cart has sat since yesterday and the voltage is 50.1, according to ScottyB's dashboard meter. It was charged with the DPI unit, but the results were the same with the QE. Temperature is right at 32 degrees.

Going by your chart, the batteries are fully charged and the reading is 'normal'. I'll have to run the cart a bit so I can see how much it drops and also so I can charge it to do the break-in sequence. My normal usage is very low, as in a couple or 3 hundred yards every week, just to haul the garbage to the burn barrel, etc. Most of the time, I don't actually use the charger, just plug in the 48-volt Battery Minder and let it top off the charge.

Twice/year, it goes to an antique engine/tractor show, where it'll get more serious mileage on it.

[cgtech]

You should be using the charger more often. The little maintainer cant do the job correctly.