New battery tips

[Conradconrad]

Originally Posted by rib33024

So I take it you have a 42 volt system?? with 7 batteries. It help a lot if in your first post that you tell us all about your cart, and then there is no misunderstanding.

Year of cart ?
Drive system ?
Volts of your cart ?

You are right! My apologies, for some reason I thought I had it all listed in my signature- I was wrong. It’s a 2007 TXT PDS with EMP motor, Alltrax XCT 500, running seven 6v batteries(42v), 2 gauge wires. Use a 42v DPI charger

[Conradconrad]

Looks like I have a faulty DVM

Battery 1 6.61
Battery 2 6.61
Battery 3 6.59
Battery 4 6.60
Battery 5 6.60
Battery 6 6.61

Pack voltage 46.3

DVM reads 42.7 but wires for the DVM at battery pack read 46.3

[ThreeCW]

Not many of us were thinking with our 42 volt hat on ... as that is not a common cart voltage .

I start out by saying that at 6.12 volts from the shop they are at a 60% state of charge. I am not to sure how long they have been laying around, but that seems to be kind of low to me (perhaps others can offer their experience).

I my experience (once only) of buy new batteries in July 2018, my Trojan T125 were 6.25 to 6.36 volts (80% to 98% state of charge) coming from the shop ... and to tell you the truth, I was kind of disappointed in having the lowest 3 of 8 batteries in the 80 to 82% state of charge range.

The problem about picking up NEW batteries at a 60% state of charge, is that they have already started to sulfate ... and the longer that they stayed at a low state of charge, the more difficult it is for that sulfate to be removed (some of the sulfate deposit can become permanent with time and kill a battery).

Looking at your 42.8 volts you achieved at the end of "charging" (which is 6.114 volts per battery average), your batteries have not achieved any increase in charge in 11 hours of "charging".

Did you hear the batteries bubble / boil at any stage of charging?

Something is definitely wrong. Possibilities include:
1) Incorrect wiring of pack
2) Incorrect wiring of charger
3) Faulty charger
4) Bad batteries
5) Faulty digital volt meter (edited after I saw your response ... must have been typing at the same time)

I would disconnect this pack from your cart and only leave it hooked up to the battery charger while troubleshooting this problem.

[ThreeCW]

Originally Posted by Conradconrad

Looks like I have a faulty DVM

Battery 1 6.61
Battery 2 6.61
Battery 3 6.59
Battery 4 6.60
Battery 5 6.60
Battery 6 6.61

Pack voltage 46.3

DVM reads 42.7 but wires for the DVM at battery pack read 46.3

Let the voltages stabilize for 12 hour after charging or so, but it looks like a healthy pack now

Make sure so break them in gently and follow the advise on Scotty's website to help maximize the battery life.

[JohnnieB]

Originally Posted by Conradconrad

Looks like I have a faulty DVM

Battery 1 6.61
Battery 2 6.61
Battery 3 6.59
Battery 4 6.60
Battery 5 6.60
Battery 6 6.61

Pack voltage 46.3

DVM reads 42.7 but wires for the DVM at battery pack read 46.3

What good does it do to only list the voltages of six of your seven 6V batteries?


The SoC chart posted by ThreeCW is for Trojan batteries, the attached chart is for US Battery.

[Conradconrad]

Originally Posted by JohnnieB

What good does it do to only list the voltages of six of your seven 6V batteries?


The SoC chart posted by ThreeCW is for Trojan batteries, the attached chart is for US Battery.

Hahahahah JohnnieB that sums how my day seems to be going. The seventh battery is 6.61

Thank you

[JohnnieB]

Ooops, just noticed that chart doesn't have a 42V pack on it and found out that I don't have one for US Battery with 42V pack listed.

Looks like I'll have to make one, but in the interim, just multiply the 2V cell voltage by 21 to get the correct values for a 42V pack.

[ThreeCW]

Originally Posted by JohnnieB

Ooops, just noticed that chart doesn't have a 42V pack on it and found out that I donl't have one for US Battery with 42V pack listed.

Looks like I'll have to make one, but in the interim, just multiply the 2V caell voltage by 21 to get the correct values for a 42V pack.

JohnnieB

When I owned US Batteries, I could not find a USB specific chart. Where does this one come from?

My new Trojan 48 pack (8 x 6v from July 2018 ) are typically 51.9 to 52.1 volts at 24 to 48 hour after charging (depending on temperature).

[JohnnieB]

Originally Posted by ThreeCW

JohnnieB

When I owned US Batteries, I could not find a USB specific chart. Where does this one come from?

My new Trojan 48 pack (8 x 6v from July 2018 ) are typically 51.9 to 52.1 volts at 24 to 48 hour after charging (depending on temperature).

Fred Wehmeyer - Senior Vice President - Product & Process Engineering at US Battery emailed it to me a couple years ago.

I'd submitted a few technical questions their on-line tech support staff didn't have answers to and they got kicked upstairs.

I also received a chart of electrolyte volume and lead weight for their deep cycle batteries.

[JohnnieB]

Attached is a SoC chart for US Battery that includes a 42V pack.

I got sidetracked with some Honey-Do stuff or I would have posted this sooner.

FWIW: I found a copy of my question and his reply. The date was Sept-2013, so the information is five years old and I've been posting the USB SoC info since then.

The original email and reply have been edited to remove phone numbers and e-mail addresses.
-------
My question:

There are numerous SoC vs Voltage charts (At-Rest Voltage) that have been posted on Golf Cart forums for years and they all boil down to the following:
2.122 VPC = 100% SoC
2.103 VPC = 90% SoC
2.083 VPC = 80% SoC
2.062 VPC = 70% SoC
2.040 VPC = 60% SoC
2.017 VPC = 50% SoC
1.993 VPC = 40% SoC
1.969 VPC = 30% SoC
1.943 VPC = 20% SoC
1.918 VPC = 10% SoC

These voltage and SoC relationships are based on testing done by the Trojan Battery Company on Trojan deep-cycle Batteries and your deep cycle batteries require a higher On-Charge voltage to be "Fully" charged, so I suspect the At-Rest voltage would also be higher.

Do you have a chart that lists the SoC vs Voltage for US Battery deep-cycle batteries, or are the charts developed by Trojan accurate for your products also?

His Reply:

John,

I should first point out that Open Circuit Voltage (OCV) vs State of Charge (SOC) data such as you have shown below is specific to individual battery types and also varies based on various factors such as battery age, previous cyclic history, temperature, and a myriad of other factors. Therefore, any published data for ‘families of batteries’ is a composite of many battery types and usually applies to new batteries.

Having said that, US Battery does have similar data for our deep cycle batteries that is very close to the data you provided. The only difference I see is at full charge where we use 2.13 vpc instead of 2.12 vpc because our full charge specific gravity is slightly higher at 1.270. The other points on the chart are nearly identical.



The answer to your other question is that the reason we use a higher ‘On-Charge’ voltage or ‘Top-of-Charge’ voltage is that over the years, US Battery deep cycle batteries have been engineered to resist the deleterious effects of overcharge which is often the primary cause of failure in deep cycle batteries. This has allowed US Battery to develop batteries that give longer cycle life under all types of charge regimes.



Following is the US Battery OCV vs SOC data.



If you have questions, please contact me.

K. Fred Wehmeyer

Senior Vice President - Engineering

U.S. Battery Mfg. Co., Inc.

1895 Tobacco Road

Augusta, GA 30906