[KBusch]

How many rounds of golf are your carts seeing say on a weekly basis?

[littleCedar]

Originally Posted by KBusch

How many rounds of golf are your carts seeing say on a weekly basis?

Maybe 7 6 or 7 months a year, and none to 2 the other months.

Today and tomorrow we will be starting the day with 130 golfers. We were expecting our factory tech today, so I had 25 carts culled out for him to look at. He didn't show and by the time I left at 1:00, I had put out all but the worst 6 or 7 carts.

On our 2008 fleet, by 2011 we had 30 carts segregated to not go out, and only 30 that could. Sometime we had to put the bad ones out, knowing we would have good ones back in when the bad ones starting dying. & they did every day.

We're heading there again, with all the same problems, and we're doing what we can to stem it off.

[KBusch]

Originally Posted by littleCedar

Maybe 7 6 or 7 months a year, and none to 2 the other months.

Today and tomorrow we will be starting the day with 130 golfers. We were expecting our factory tech today, so I had 25 carts culled out for him to look at. He didn't show and by the time I left at 1:00, I had put out all but the worst 6 or 7 carts.

On our 2008 fleet, by 2011 we had 30 carts segregated to not go out, and only 30 that could. Sometime we had to put the bad ones out, knowing we would have good ones back in when the bad ones starting dying. & they did every day.

We're heading there again, with all the same problems, and we're doing what we can to stem it off.

You have a combo of issues. Sounds as though you have issues with the watering system, but I'd also say the carts having the 4 12 volts in them is also an issue. We know, 4 12volts don't work very well. Your next fleet you will be OK, and Im sure the manufacturer will take care of it.

[littleCedar]

Speaking of . . .

Factory tech was here today. He doesn't care about low voltage readings, unless they're in the 10's.

But he does care about "hot" batteries, ones that get hot when charging. We've got some more of those, so I'll be using the laser thermometer.

I also will not stop taking voltage readings, since we are having problems with some of those carts.

Also, nothing has been done, or even suggested something will be done, about the autofills not working.

It feels like 2011 all over again, when 1/2 our fleet could not even go out on the course. If you will look at the other forum I linked to, I was working on those problems, trying to get the manufacturer to listen to us from August, 2009:

08-04-2009, 06:01 PM #1
cartboy
Gone Wild

Join Date: Aug 2009
Posts: 329 RXV Auto Brake Problem
--------------------------------------------------------------------------------
RXV Auto Brake

Looks like I will be the one to burst the bubble.

I'm searching for others who are having problems with the new rxv auto-brake.

Our fleet of 60 have been in service since last Fall and they are just now exhibiting problems . . . specifically, the auto-brake is locking up. About a couple each day now.

Bummer.

Anyone else?

Since it is new technology, we have to share our experiences. The fix, whatever it will be, will be a new fix . . . for a new problem.

(guess we're the Guinnea pigs on this one)

Let's work together to find out what's wrong.

[KBusch]

EZGO has always been concerned about a "hot pack", even when the cars were 36 volts. Since your checking voltages all the time you should be able to find the ones that are holding the pack up, remove those batteries and put one in that you know is good, that way it wont ruin the other batteries in that set. Granted it is a lot of work, rather than wait for the factory to come in and do something. OR you can just wait until they fail and let them deal with it. I've taken care of many fleet cars and you can score major points with management (and possible raise) by showing you know what is going on.

[littleCedar]

I know you know what I know.

I have been self-educating via the Internet on deep cycle battery technology for about five years, since I set up a solar electric system for our boat dock.

I know I'm at a roadblock now with our factory tech, and I'm hoping someone viewing can help me.

What I want to know is how voltage readings on a full charge affect both remaining useful life and what a battery can do on each charge (how many holes/rounds of golf).

Common sense tells me that four batteries reading 12.8 volts at full charge are better than four batteries reading 12.1.

Anyone?

[ajbrown]

Originally Posted by littleCedar

I know you know what I know.

I have been self-educating via the Internet on deep cycle battery technology for about five years, since I set up a solar electric system for our boat dock.

I know I'm at a roadblock now with our factory tech, and I'm hoping someone viewing can help me.

What I want to know is how voltage readings on a full charge affect both remaining useful life and what a battery can do on each charge (how many holes/rounds of golf).

Common sense tells me that four batteries reading 12.8 volts at full charge are better than four batteries reading 12.1.

Anyone?

I am going to post this link with the assumption you have seen it. Nice SOC chart at bottom of link.

Trojan Battery Company

<!-- I am a DIY guy with a huge fleet of two carts, so caveat reader -->

It is hard to know how far carts will go. Even if a battery will take a full charge (> 12.73) it may still fail under load. That said, the fact it will take a full charge is a good starting indicator that the battery is ok.

IMO, a battery that can only be charged to 12.1 is no good or on the edge of no good. It is already at 50% capacity. That battery will impact the whole pack and will be extremely hard to predict range. As the pack discharges that battery will go much quicker than the others. That battery will have a negative affect on the pack during load and also when charging. The only way I know of to predict capacity is a discharge test, or a poor man's discharge test, taking voltages after 18 holes, then after 36 once in a while.

This statement here by the dealer is crazy to me:

Factory tech was here today. He doesn't care about low voltage readings, unless they're in the 10's.

In the 10s ?. A battery that is in the 10s is dead. That seems crazy to me, or I am about to learn something new when someone straightens me out...

See, we are still interesting in sparky conversations....

[littleCedar]

From my self-study, a reading in the 10's means a shorted cell. Something in the 11's means all cells are still doing something.

As far as the factory tech, I agree. Heat is a problem, but so is low voltage readings. Every tutorial I've looked at suggests taking voltage readings on fully-charged batteries, after "burning off" a bit, say by turning on the headlights a short time.

I am trying to establish exactly how to interpret low voltage readings then.

That is as opposed to what I am considering to be OK, all four reading 12.5 or above.

In any event, I am trying to stay ahead of our debacle on the 2008's, when I first detected problems in August, 2009, and by 2011 half our fleet was not suitable to go on the course, because nothing was done until it was too late. Even after 117 batteries were replaced, it was still too late. I am not given much credit for having gone this before.
- - - - - -
As an example: going by the chart in the link, the same or similar as several others I have found, if a battery reads 12.1, and is at "50% of charge", does that mean it will discharge under use in 50% fewer holes on the golf course, or does that mean that 50% of its useful life is over, but it will still do as many holes per charge, or some combination?

It certainly does not sound OK to be at 50% of charge when it is "fully charged".

From the several tutorials online, it is fairly obvious that the closer a reading is to 12.0, the nearer a battery is to end-o-life. So, what about three reading 12.4, and one reading 12.1, or three reading 12.1, or four reading 12.3? Will multiple low-reading batteries reduce holes per charge?

etc., etc., etc.

[ajbrown]

Originally Posted by littleCedar

<stuff snipped by Alan for brevity>

As an example: going by the chart in the link, the same or similar as several others I have found, if a battery reads 12.1, and is at "50% of charge", does that mean it will discharge under use in 50% fewer holes on the golf course, or does that mean that 50% of its useful life is over, but it will still do as many holes per charge, or some combination?

It certainly does not sound OK to be at 50% of charge when it is "fully charged".

From the several tutorials online, it is fairly obvious that the closer a reading is to 12.0, the nearer a battery is to end-o-life. So, what about three reading 12.4, and one reading 12.1, or three reading 12.1, or four reading 12.3? Will multiple low-reading batteries reduce holes per charge?

etc., etc., etc.

50% state of charge is an indicator of how much energy is left in the battery for this charge cycle, i.e., how many holes it will go. It is not an indicator that it has 50% useful life left. In fact a battery that can only be charged to 50% SOC is likely nearing end of life. IMO that is very low.

Here is a graph I did some time ago in which I tracked the pack voltage for two separate rides. All packs will have their own line if you were to chart them during usage as I did. The cart charted below had a good pack and could go quite far as it has 8-6v batteries.

Based on my chart the cart looks like it could theoretically go about 75-80 miles before causing great harm to the pack. Now look at the same line but start at 50% SOC. Looks like I could go 32-35 miles if I started with an SOC of 50%.

[littleCedar]

The failing autofills are an issue on the back burner now. It does not even come up with our factory tech.

The truth of it is that there does not appear to be a correlation between low voltage readings, failed autofills, corroded terminals, or which battery. It seems to be random.

Our tech told me he does not care about voltage readings, just batteries that are hot when they are charging. We are taking readings of that, too. Most are 80-90° when charging. The hot ones are 130-140°.

I have self-studied deep cycle batteries for a number of years, starting when I put together a solar electric system for a boat dock.

The general axiom has always been that the closer a 12-volt battery gets to 12.0 volts at full charge, the closer it is to being toast. I have emails from "battery people" to that affect.

In the last week I have visited a half-dozen websites tutoring on solar systems, RVs, golf carts, etc., and most of them agree with that. Most of them have tables like this:

State of Charge Voltage

100% 12.7
75% 12.4
50% 12.2
25% 12.0
Discharged 11.9

Or, here is 11.9 on another one:

20% (Cells die soon at this point. Bye-bye battery.) 11.80-12.00

and here's another one:

Discharged 11.90

But, both E Z Go and US Battery have sent me their tables. I won't post it all, but they are saying 11.9 is:

40% 11.96

So, figure it out for yourself . . . the battle I will be up against.

[littleCedar]

Originally Posted by ajbrown

50% state of charge is an indicator of how much energy is left in the battery for this charge cycle, i.e., how many holes it will go. It is not an indicator that it has 50% useful life left. In fact a battery that can only be charged to 50% SOC is likely nearing end of life. IMO that is very low.

Here is a graph I did some time ago in which I tracked the pack voltage for two separate rides. All packs will have their own line if you were to chart them during usage as I did. The cart charted below had a good pack and could go quite far as it has 8-6v batteries.

Based on my chart the cart looks like it could theoretically go about 75-80 miles before causing great harm to the pack. Now look at the same line but start at 50% SOC. Looks like I could go 32-35 miles if I started with an SOC of 50%.

So, as indicated in my last post, it is all about what is considered 50%, or 20%, or discharged.

For a 48-volt system, some references show 20% State of Charge to be 48 volts; yours 46.62; another 46.32. Trojan has it at 46.64. E Z Go & US Battery has it at 47.92.

Well, it can't be all of them.

I checked a cart with brand new batteries, with a full charge, and it was 12.79, 12.80, 12.74 & 12.79 = 51.12.

When I check carts we are having problems with, dying on the first 18, I get readings like 12.1 on one battery. According to your graph, four batteries reading 12.1 are at 50%, so the cart would likely be dying on the course fairly quickly.

I went out to exchange one cart, and the guy in the foursome behind that one thought we came for his! The guy following me to push me back in gave his cart to the other guy. So, neither of us made it back in. Those two carts each had readings of 12.3 in 3 batteries, and 6.3 in the fourth. That would be 43.2, and they were still limping along on level ground.

Regardless, we should not be having these problems with one-year-old, top-of-the-line carts.

I'm doing my best to draw conclusions, and report to my higher-ups, with an inexact science.

[littleCedar]

It's kinda funny really . . . if you want your batteries to last longer, you just put out a table with low voltages on it.

[littleCedar]

Just for yucks, here's the table figures for 12-volt batteries. The Tech says they will not replace one unless it is down to 10.5 volts after 55 minutes.

I have not found any other deep cycle battery table that says a 12-volt battery reading less than 12-volts when fully charged is any good at all.

Anyone else?


TABLE 1. State of charge as related to specific gravity and open circuit voltage

Percentage of Charge


100
12.73

90
12.62

80
12.5

70
12.37

60
12.24

50
12.1

40
11.96

30
11.81

20
11.66

10
11.51

[KBusch]

Big business product support guys are told to play it down. If you ask them they wont be able to remember the last time they heard about one of their carts breaking.

Just forget about what they tell you and go with what you know...they will come around, most of the time when it goes to a major catastrophe.

I was told by a battery company that it was ok for those 12 volt batteries to be charging in the 16 volt range. This was suppose to be coming from a battery expert. Hang tight, let the batteries fail, and they will come to the rescue if they want to keep the course.

[littleCedar]

Originally Posted by KBusch

Hang tight, let the batteries fail, and they will come to the rescue if they want to keep the course.

As they did in 2011, when they replaced 117 batteries, and then gave up and redid the lease with new carts.

I am just trying to prevent the two rows of carts that could not go out on the course while we waited for them to take action.