High Battery Voltage?

[bobbycason]

Yeah I've come to terms with that I found someone by me that has Trojan t605s for $80 so that's probably the route I'm going to go and possibly an upgraded in a few months.

[cgtech]

605 are the cut rate batteries, lower than normal capacity. It not only means shorter run times between charges, but also shorter overall lifespan. Deeper discharge per use shortens life.

[R.Boyd]

I have 5 batteries that are the same age that went through the same treatment as yours. I checked them before charging them and they all showed 5.7 volts except one which was 3.7. After charging they all showed 6.2 volts. One was missing due to a melted post. I used 4 and put a car battery in there to test it just as was suggested above and it ran surprisingly well.

[bobbycason]

How long did you use it like that?

[R.Boyd]

Not long. About 30 min two days in a row, so about an hour. Charged between days. Didn't seem to really loose much charge in that amount of riding. I was just testing the motor and controller. Fixing to buy some batteries.

[R.Boyd]

The 12 volt battery was first in line hooked to the positive lead. Was pushing 16 to 17 volts during charging to it. Was a little worried about that.

[ThreeCW]

When I bought my cart, it had 8 pieces of 242 AH x 6 volt batteries that were about 3-1/2 years old, with slightly swelled cases (sulfated?) which I suspect were not cared for too well. All batteries were in the 6.28 volt to 6.47 volt range after being charged and allowed to stabilize for 12+ hours with a 51.0 pack voltage. In about 3 months, one battery failed when I tried to "desulfate" the pack. I replaced the bad battery (4.25 volts) with a "new blemished" battery rated at about 230 AH.

All was well for about 4 months, when 7 of the 8 batteries in my pack were 4 years old and another of the batteries failed (complete short - no voltage) and once again I replaced the failed battery this time with a "good used" one.

I ran the battery pack for another year with the batteries now over 5 year old and another battery failed ... down to about 4 volts I recall. At which time, I bit the bullet and replaced the whole pack with new Trojans.

So I believe that YES, you can replace your failed battery with a "good used" one and get a month or two ... perhaps even a year out of the pack, until you are in a position to replace the entire pack and perhaps upgrade to 48 volts.

Just my 2 cents ...

Regards, 3CW

[cgtech]

A single battery in a series "string" cannot "draw down" the rest in the way you may be thinking (or it would be a really nice heater box, getting hot). BUT, any set of batteries in a series configuration is limited to the "weakest link in the chain", or your worst battery. The worst one determines how well the system works. The worst one determines just how far you can drive before performance suffers. And, the worst one also limits just how well the others can charge. Your charger sees all of your batteries as a big string and it cannot tell which battery is stronger or weaker. your charger treats them all like they were one single big battery. so your weakest battery will get to full charge and beyond full charge way before all the rest get to fully charged.

[bobbycason]

Originally Posted by cgtech

A single battery in a series "string" cannot "draw down" the rest in the way you may be thinking (or it would be a really nice heater box, getting hot). BUT, any set of batteries in a series configuration is limited to the "weakest link in the chain", or your worst battery. The worst one determines how well the system works. The worst one determines just how far you can drive before performance suffers. And, the worst one also limits just how well the others can charge. Your charger sees all of your batteries as a big string and it cannot tell which battery is stronger or weaker. your charger treats them all like they were one single big battery. so your weakest battery will get to full charge and beyond full charge way before all the rest get to fully charged.

So this would somewhat explain why the amp meter on the charger stays on the lower end now (>10amps)?

[bobbycason]

Originally Posted by ThreeCW

When I bought my cart, it had 8 pieces of 242 AH x 6 volt batteries that were about 3-1/2 years old, with slightly swelled cases (sulfated?) which I suspect were not cared for too well. All batteries were in the 6.28 volt to 6.47 volt range after being charged and allowed to stabilize for 12+ hours with a 51.0 pack voltage. In about 3 months, one battery failed when I tried to "desulfate" the pack. I replaced the bad battery (4.25 volts) with a "new blemished" battery rated at about 230 AH.

All was well for about 4 months, when 7 of the 8 batteries in my pack were 4 years old and another of the batteries failed (complete short - no voltage) and once again I replaced the failed battery this time with a "good used" one.

I ran the battery pack for another year with the batteries now over 5 year old and another battery failed ... down to about 4 volts I recall. At which time, I bit the bullet and replaced the whole pack with new Trojans.

So I believe that YES, you can replace your failed battery with a "good used" one and get a month or two ... perhaps even a year out of the pack, until you are in a position to replace the entire pack and perhaps upgrade to 48 volts.

Just my 2 cents ...

Regards, 3CW

Thanks for the info. There's also a place not far from me that has "reconditioned" batteries for $40-$50 so I may try one of those before biting the bullet on a full set. I ultimately want to upgrade to 48volt but don't want to spend that money right now between batteries and charger.