Battery charging and testing questions....

[SHIMHEAD]

Hello all,
I have the voluntold duty of trying to get an inherited golf cart up and running for my sister-in-law. So here goes. 48v cart, unsure of the make model at present. I have 5 of the Trojan T-875 batteries in my posession, the 6th one was in the process of being "Rejuvinated" by my father-in-law before he passed away using epsom salts. So I checked open circuit voltage of the batteries I do have finding them all at approximately 7.83 volts give or take a couple hundreths. Trojan website says 30% state of charge for that terminal voltage. I purchased an Autometer BEX-500 charger that has an 8 volt setting, and have been charging the first battery for over 36 hours, with it still showing the "Charging" LED on. I have a hydrometer, but have not yet performed specific gravity cell tests. The battery I am charging does not seem to be getting warm (charger is getting warm). The charger has a 5 amp max charge rate, fully automatic. I also have a carbon pile load tester for 12 volt batteries at my disposal. Looking for advice on how best to proceed charging and testing the batteries from this point. I also have at my disposal several different 12 volt chargers, all the way up to a wheeled automotive Snap-On fast charger (80 amp capable I believe) which only has charge rate and timer functions.
As a separate but related question, has anyone used an RC car battery charger with a Pb (Lead-Acid) setting to charge a cart battery? I have seen several with settings for Pb voltage from 2-20 volts, with charge rates as high as 20 amps. Really curious about possibly using one of those, maybe in an equalizing charge set to 10 volts instead of 8 volts.
For what it is worth, I am a 40 year automotive technician "Veteran" with loads of 12 volt battery experience, not so much with 8 volts.

Thanks in advance for any advice or information...

I might have posted in the wrong location, so please move the post as needed!

SHIMHEAD

[JohnnieB]

Since the cart has a 48V battery pack made up of six 8V batteries connected in series, a 48V battery charger is needed.

Granted, it is possible to charge the batteries individually with a 8V charger, but it isn't practical time-wise and keeping the pack equalized would be challenging.

The deep cycle batteries used in golf carts are a different breed of animal than the SLI (Start, Lights, Ignition) batteries used in automotive applications and just about all test equipment designed for automotive SLI batteries are not suitable for deep cycle batteries. Same voltmeters, ammeters, hydrometers or refractometers and non-conductive handtools can be used, but that's about it.

Attached is a User's Guide from Trojan Battery for their deep-cycle lead-acid batteries.

The main difference between a 12V battery and a 8V battery is the number of 2V cells packed in the box. If the 12V and 8V batteries are packaged in the same sized box, the 12V battery will have a lower AH (Amp Hour) rating because the 2V cells have to be physically smaller to fit two more of the in the same sized box.

[SHIMHEAD]

Thanks JohnnieB,
I had already downloaded and read the Trojan document. Could I ask your opinion, given the lack of information, if you think it's worth trying to charge the 5 batteries I have?
Also, any input on the RC car charger question??

SHIMHEAD

Moderator, please move thread to Club Car Electric. Just learned cart is a 1999 DS. A9904-741505

[JohnnieB]

Since the 5 batteries had been sitting for a while without being charged, they are most likely kaput.

I know nothing about RC car chargers.

[Powercat]

From experience, the epson salt trick "can" really work. Just depends how gone they are, and how much build-up they have on the plates. I got 3 1/2 years more life out of a set of Duracells that had set for over a year. They never came up to the full voltage they should have as a pack, 51v versus >54v, but they still got you around. Batteries are seldom kaput, when you think they are.

[cgtech]

Yeah, if you wanna drive from the garage to the gate, just about any trick will get that job done. Try playing a round of golf. If those tricks worked so well, everyone would be raving about how it saved them. Look around, none of the "well known" tricks did much more than a quick "party trick" to do anything. Not a good story about how "it got my batteries back to really good range" to be found. Nothing was done that several back-to-back charges & drives wouldnt have done. Once a battery is damaged, its damaged. Epson salts might "burn the crud" off the plates to give a little boost, but it is actually detrimental to the plates of the battery. I believe "charge, charge, discharge, charge, charge, discharge" would do the same, without burning the plates with ingredients that dont belong in a battery.

[Bama Brad]

Originally Posted by SHIMHEAD

Hello all,
I have the voluntold duty of trying to get an inherited golf cart up and running for my sister-in-law. So here goes. 48v cart, unsure of the make model at present. I have 5 of the Trojan T-875 batteries in my posession, the 6th one was in the process of being "Rejuvinated" by my father-in-law before he passed away using epsom salts. So I checked open circuit voltage of the batteries I do have finding them all at approximately 7.83 volts give or take a couple hundreths. Trojan website says 30% state of charge for that terminal voltage. I purchased an Autometer BEX-500 charger that has an 8 volt setting, and have been charging the first battery for over 36 hours, with it still showing the "Charging" LED on. I have a hydrometer, but have not yet performed specific gravity cell tests. The battery I am charging does not seem to be getting warm (charger is getting warm). The charger has a 5 amp max charge rate, fully automatic. I also have a carbon pile load tester for 12 volt batteries at my disposal. Looking for advice on how best to proceed charging and testing the batteries from this point. I also have at my disposal several different 12 volt chargers, all the way up to a wheeled automotive Snap-On fast charger (80 amp capable I believe) which only has charge rate and timer functions.
As a separate but related question, has anyone used an RC car battery charger with a Pb (Lead-Acid) setting to charge a cart battery? I have seen several with settings for Pb voltage from 2-20 volts, with charge rates as high as 20 amps. Really curious about possibly using one of those, maybe in an equalizing charge set to 10 volts instead of 8 volts.
For what it is worth, I am a 40 year automotive technician "Veteran" with loads of 12 volt battery experience, not so much with 8 volts.

Thanks in advance for any advice or information...

I might have posted in the wrong location, so please move the post as needed!

SHIMHEAD

If you are going to have to replace batteries and charger, I would consider going with Lithium. The drop ins come with charger and BMS, simple hook up and go. Lighter & much better performance, no maintanance.

[JohnnieB]

Originally Posted by Powercat

From experience, the epson salt trick "can" really work. Just depends how gone they are, and how much build-up they have on the plates. I got 3 1/2 years more life out of a set of Duracells that had set for over a year. They never came up to the full voltage they should have as a pack, 51v versus >54v, but they still got you around. Batteries are seldom kaput, when you think they are.

By "kaput", I meant the end of their useful lifespan and the definition of useful is defined by the specific application and owner expectations.

I built my cart to have a >30 mile range on a single charge by installing a 42V pack made up of seven 245AH 6V batteries (10.3kWh storage capacity vs the 8.1kWh of a standard 36V or 48V pack) and anticipated a 3 to 5 year useful lifespan. That was 8 years ago in Nov-12, but I seldom drive my cart on more than 10 mile trips these days, so I may get twice, or more, the expected useful lifespan since the range requirement changed.

----------
The Epsom salt (magnesium sulfate) and some of the other snake oil remedies can work, but they can also kill battery cells. What they do is make the outer layer (sulfated layer) of the plates slough off, exposing fresh lead and lead dioxide. The sloughed of material is conductive and builds a bridge between adjacent plates, shorting out the cell and rendering the battery unusable. That bridge can form almost instantly when the snake oil is added, or at any time afterwards when the sloughed off material that has settled to the bottom of the cell is agitated during normal cart operation. In other words, every time the cart is taken out it might leave you stranded when a cell shorts out.

If those are acceptable risks, go for it. Be sure to carry your cell phone with you.

-------------
FWIW: The highest 100% SoC I know of for lead-acid, wet-cell, deep-cycle batteries is US Battery brand batteries at 51.29V. The 100% SoC for Duracell is 50.93V.

[JohnnieB]

Originally Posted by cgtech

Yeah, if you wanna drive from the garage to the gate, just about any trick will get that job done. Try playing a round of golf. If those tricks worked so well, everyone would be raving about how it saved them. Look around, none of the "well known" tricks did much more than a quick "party trick" to do anything. Not a good story about how "it got my batteries back to really good range" to be found. Nothing was done that several back-to-back charges & drives wouldnt have done. Once a battery is damaged, its damaged. Epson salts might "burn the crud" off the plates to give a little boost, but it is actually detrimental to the plates of the battery. I believe "charge, charge, discharge, charge, charge, discharge" would do the same, without burning the plates with ingredients that dont belong in a battery.

[SHIMHEAD]

So the 1st battery reached the "Charge complete" stage on the charger after approx. 48 hours charging. Moved charger to second battery. Will test terminal voltage and specific gravity tomorrow and update. Any suggestions on load testing with the carbon pile load tester (ES 710, 500 amp)? Standard automotive routine is 1/2 CCA or 3 x AH rating for 15 seconds, looking for above 9.6 volts at 70 degrees F. By my calculations that is about a 34% voltage drop threshold from a starting 12.6 volts. 34 % drop from 8 volt battery full charge of 8.49 volts comes to 5.61 volts. Not sure how much to load the battery however. Here is the battery data sheet:
https://www.trojanbattery.com/pdf/da...ata_Sheets.pdf . Open to suggestions.....

SHIMHEAD