T105's in 1999 EZGO not lasting

[radioman]

What kind of water do you use to top them off? Distilled water is best.

[JohnnieB]

Originally Posted by sportcoupe

He has no SOC meter and guessed at how far he was discharging the batteries. You can get ~1300 cycles (3.5 years) if you only discharge to 50% SOC. If he discharged further that number is dramatically reduced. See attached chart.

It occurred to me that the projected life expectancy estimates on that chart are based on one discharge/charge cycle per day and the batteries we are talking about is being discharged and charged twice a day.

That presents an interesting question: Would the batteries last longer if only charged once a day?

Charging them more often uses more charge cycles, but charging more often also raises the average SoC maintained, so the number of charge cycles available is higher. The latter offsets the former to some degree, but without know how deeply the batteries are being discharged, I have no idea how much.

It could very well be that the batteries, as beau alluded to, are simply being used up in two years by the workload imposed on them.

Looking forward to some SoC values.

[april]

OK, I've got some more info for you guys.
First, the tires are 18x9.50-8, pretty close if not stock.
We figure we travel a couple of miles doing chores, but not exactly sure.
It's a series drive cart.
I always add distilled water to batteries needing it.
We checked the batts before chores this morning: 38.7
After chores (no mud today, batteries still felt strong at the end) : 37.5
So, according to today's numbers, we should be fine. However, in the last couple of months we have had the cart **** near die on us and barely limp back to the barn.

I'll check the batteries again tonight.

[april]

This afternoon the charger was still running, batteries pack was 40
After chores: 37.3

I am also wondering how much the extreme cold we had last month was affecting the batteries. They seem to be working better now than they were a month ago, so maybe it was the weather?

Someone mentioned a more modern charger. Can I get some details? What kind and where to buy?

Thanks for all your help!

[sportcoupe]

Originally Posted by april

Someone mentioned a more modern charger. Can I get some details? What kind and where to buy?

ScottyB is a respected member here and a site sponsor. He sells a DPI charger that is highly recommended.

http://www.cartsunlimited.net/48v_Battery_Charger.html

[JohnnieB]

Originally Posted by april

OK, I've got some more info for you guys.

1. First, the tires are 18x9.50-8, pretty close if not stock.

2. We figure we travel a couple of miles doing chores, but not exactly sure.

3. It's a series drive cart.

4. I always add distilled water to batteries needing it.

5. We checked the batts before chores this morning: 38.7

6. After chores (no mud today, batteries still felt strong at the end) : 37.5
So, according to today's numbers, we should be fine. However, in the last couple of months we have had the cart **** near die on us and barely limp back to the barn.

I'll check the batteries again tonight.

Originally Posted by april

7. This afternoon the charger was still running, batteries pack was 40
8. After chores: 37.3

9. I am also wondering how much the extreme cold we had last month was affecting the batteries. They seem to be working better now than they were a month ago, so maybe it was the weather?

10. Someone mentioned a more modern charger. Can I get some details? What kind and where to buy?

Thanks for all your help!

1. The size stamped on the tire's sidewall is notoriously inaccurate, but usually within an inch or so, so your tires are probably between 17" and 19" tall, and probably not Anp hogs unless they are low pressure tires. (Max inflation 10 PSI or less).

2. If possible, carry a GPS or smart-phone with GPS App with you. If we knew the distance traveled and the At-Rest pack voltage before and after the trip, we could calculate how many AH the cart used per mile. Knowing that would help figure out what is making the battery lifespan so short.

3. That is a good drive system for the type work being done.

4.

5. That is a bit high, so the charger hasn't been off long enough for the surface charge to deplete. That takes about 12 Hours. What time were the batteries put on charge and what time were the voltages read the next morning?

6. 37.5V = about 80% SoC, or it took about 45AH to travel a "couple" miles. (If the batteries were 100% charged and had 225AH storage capacity.)

7. At what time in the morning were the batteries put on charge?
At what time was the charger disconnected that afternoon?
How soon after the charger was disconnected, was the voltage reading taken?

If the time was over six hours, the charger shouldn't have been still running since the batteries were at 80% SoC.
If the voltage was read within a minute or so of the charger being disconnected, the voltage ought to have been higher.

This is pointing in the direction of battery charger issues.

8. 37.3V is about 75% SoC so the batteries were not fully charged or it took 5% more AH to travel the same distance, or the distance was 5% longer.

9. Temperature is a significant factor. According to Trojan, their batteries have 100% of their rated storage capacity at 80°F and only 50% at 0°F, so the available AH of a T-105 drops by about 15AH for every 10°F under 80°F.

10. The DPI charger sportcoupe linked to is the best thing since sliced bread.

However, chargers are voltage specific and upping the pack voltage is a way of getting more battery lifespan. More correctly, carrying more batteries, which in turn increases the pack voltage.

Basically, your cart was designed to carry two golfers and their clubs over groomed cart trails for 18 holes on a single charge. To do much more than that, the drive system needs to be upgraded.

Replacing the voltage specific 275A stock controller and 85A solenoid, with a 400A controller with appropriate solenoid will give you the additional torque needed for carrying heavy load through mud. Adding another 6V battery or two will give you 16.7% or 33.3% more stored energy.

Seven 6V batteries will fit under the seat without any modifications. To run eight 6V batteries, one or two have to go in the bag well, or some modifications are needed to put them all under the seat.

[april]

Well, I just got off the phone with Scotty, I ordered one of his chargers plus a volt meter. Hopefully I can get more life out of my next set. Now to decide if I should go with the 105 again or bump up to the 145.

[beau]

I've would go for the 145's , sounds like you may need that xtra run time.


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[april]

Another question. Is it normal for the cart to stop pulling but still have 36+ volts? We have had to push it to the barn a couple of times and the volt meter says between 36 and 37 (I don't remember the exact numbers).
Or is it normal to be "dead" at 50%?

[JohnnieB]

Originally Posted by april

Another question. Is it normal for the cart to stop pulling but still have 36+ volts? We have had to push it to the barn a couple of times and the volt meter says between 36 and 37 (I don't remember the exact numbers).
Or is it normal to be "dead" at 50%?

No, it would be normal for the cart to be moving at 50% unless the batteries had severely sulfated plates. (IE: At or near the end of their useable life)

What was the pack voltage while the cart was trying to move and not succeeding?