New T105 Battery Voltages differences different code dates

[orangeman6]

Originally Posted by JohnnieB

The spread has gone from 0.19V to 0.16V in a bit over three weeks, so whatever radioman is doing, I'd keep doing it until no more improvement is seen.

There is not standard expectation on date codes that I know off, other than trying to get them as close as possible and as new as recent as possible.

Take a DVM with you.

Thanks JohnnieB.

When getting new batteries, is there a range in that spread of voltages that you would try to stay in?

[JohnnieB]

Preferably within about 0.1V from highest to lowest.

[BobBoyce]

Originally Posted by radioman

Update: Checked the voltages on new T105 batteries after a month in service. The three code date C7 batteries with the slightly higher voltage (2@6.57-1@6.49 volts) has not changed. The three code date L6 lower voltage batteries increased .03 volts from 6.38 to 6.41 volts.

This is often normal to see. The reason for the differences is that the battery manufacturers buy their plates in bulk, and those bulk plates are often very close in composition (metals blend) to one another. Buying batteries with a month or more build date, quite often the plates will be of slightly differing composition. This results in a slightly differing cell potential (voltage) at all stages of charge. For a golf cart, where all batteries are in series, it's not really going to affect operation in the long run. It is ampacity (amperage capacity) of the batteries that need to match in order to ensure that all cells are fully charged.

With solar power installations, where batteries are often in series/parallel strings in a battery bank, knowledgable buyers will typically reject any batteries that do not have matching date codes. This is specified at the time that the batteries are ordered, all must have matching date codes.

Bob

[radioman]

Originally Posted by orangeman6

That's good that they've come up some. I'm anxious to hear what guys think about the voltage spread now. Should radioman keep trying to bring them up with a 6 or 12v charger? What spread in voltages would we call acceptable?

Another question, and sorry to hijack: is there a standard expectation of date code similarities when purchasing new batteries? Should I take a dvm with me and check voltages as well, when getting new ones?

I quit trying to equalize the new battery voltages with individual charging. It made no difference at all so I just decided to leave them alone and enjoy the cart. I would suggest getting batteries with the same code date if possible. I am happy with them. I will post update on voltages within a month or so.

[radioman]

Update: I checked the individual battery voltages this morning. There has been no significant change in the individual readings. Readings mostly slightly lower (.01-.02 volts). Terminal bank voltage measured 4/21/2017 39.01 volts. Today 5/29/2017 measured 38.89 volts. Three code date comparing 4-21-2017 / 5-29-2017 L6 measured 6.43/6.42, 6.42/6.40, 6.43/6.41 volts. Three code date C7 6.59/6.58, 6.51/6.48, 6.61/6.60 volts.

[radioman]

Originally Posted by radioman

Update: I checked the individual battery voltages this morning. There has been no significant change in the individual readings. Readings mostly slightly lower (.01-.02 volts). Terminal bank voltage measured 4/21/2017 39.01 volts. Today 5/29/2017 measured 38.89 volts. Three code date comparing 4-21-2017 / 5-29-2017 L6 measured 6.43/6.42, 6.42/6.40, 6.43/6.41 volts. Three code date C7 6.59/6.58, 6.51/6.48, 6.61/6.60 volts.

It has been almost a year since I installed these batteries. I noted a small difference in the individual voltages of the batteries having different code dates when I put them in service. I measured the bank of batteries today after full charge April 6, 2018. The code dates still have a voltage spread as they did when purchased. The three L6 code date batteries measure 6.46, 6.44 and 6.45 volts. The three C7 code date batteries measure 6.67, 6.54 and 6.67 volts. The terminal bank measured 39.25 volts.

I have had no issues with them. They get loving care, charging after each use, distilled water, etc. I was not successful in attempts reduce the small voltage spread charging individual L6 batteries. Mostly a waste of time.

[radioman]

It has been almost 5 years (Feb 26, 2017) since I put these batteries in service. They are still in service and doing a good job. I have taken good care of them using only distilled water and charging after each use. The batteries with the initial difference in voltage still exist. After charging and waiting about 12 hours I checked the terminal voltage of each battery as follows. The three batteries with code date L6 Measured 6.39, 6.33 and 6.38. The three code date C7 measured 6.53, 6.49 and 6.51. The terminal voltage measured 38.63.

[JohnnieB]

[radioman]

Update to old thread: One battery (Trojan T-105 put in service Feb 2017 code date C7) has finally failed. The rest of the batteries are still holding up. The code date L7 battery plates look sulfated while the C7 code dates look like they have been over charging. I replaced the one failed battery with non-Trojan brand to utilize the last bit of life out of the surviving 5.