Reduced run time. HELP!

[tyhuck]

I was riding my cart around this weekend with my son and my father-in-law. We were riding through the peach orchard for about 30 minutes at about half throttle or less, and the cart just quit pulling. I let it set about 10 seconds and it seemed like it was full power for about 5 minutes more, and then quit again. Another 10 second rest and we were off again, and I made it back to the house.

It had only been about a week since the cart was charged, and it had not been run since the charge. My battery gauge was reading about 37.6 at rest, and 35.? under load. All together the passengers total weight was around 500 lbs. Im also running some pretty aggressive 22" tires, and my batteries are almost 2 years old. This is the second cart Ive had these batteries in, and its the first time its ever done this.

My previous cart was a Marathon set up the same way, and it never missed a beat. Seems like the newer electronics on this 96 TXT would run loner on a charge than the old resistor cart did. However, I have also noted that the full charge reading on my cart is lower with this newer cart and new DPI charger. The Marathon charger would get em up to 39-41 volts, an would show a voltage over 39 volts after a 24hour rest. The new DPI charger only gets it up to 38.8, even under float charge.

This is only my second cart, and my first set of batteries, so Im still a novice, and Im just looking for some insight as to whether this is normal given the conditions I was running the cart, or if I have something going out on my cart. Any insight you guys may have would be appreciated.

[JohnnieB]

Sounds like the controller is going into thermal shutdown.
Going slow for a long period of time (30 minutes) with a heavy load (500 pounds) on oversized tires (22") will do that.

What drive system do you have, Series or DCS?
(If it has a Run/Tow switch, it's a DCS)

What controller do you have, stock or aftermarket?

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You say it has only been a week since the batteries were charged.
Does that mean the DPI charge has been disconnected from the cart for a week?
If so, you are not using the DPI charger properly.
In a nutshell, if the cart is not moving, the DPI charger ought to be plugged into it.

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A cart with an electronic speed controller should be more efficient than a resistor cart, but if the oversized tires are the low pressure type, it might not be.
What is the max inflation pressure stamped on the sidewall of your tires?
If it is below 10 PSI, they are likely to be amp-hogs.

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Your voltage readings don't sound right.
The Marathon charger should have charged the battery pack into the 44 to 46 Volt range before it shutoff and after the pack rested for 12 hours, the voltage should have been about 38.2V. At 24 hours, they should have been slightly lower.
Lead-Acid batteries typically self-discharge at about 1% SoC per day.

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What Make/Model batteries do you have?
The DPI comes with Mode-2 selected (Trojan Battery).

In that mode, it stays in the bulk charge phase (constant current) until the pack voltage reaches 42.3V, then switches to absorption charge phase (constant Voltage) until the current flow drops to a predetermined rate of change, then switches to the finish phase until the change in voltage over the change in time (dV/dT) meets a predetermine rate. The pack voltage may reach as high as 50.2V, but usually doesn't get much beyond 46V.

When the regular charge cycle terminates, the charger goes into the Float charge mode and the voltage is maintained at 39.4V (in Mode-2).

If you are not getting voltage readings similar to what I have mentioned, there is an issue with your voltmeter, your battery pack or the DPI charger.

[tyhuck]

Originally Posted by JohnnieB

Sounds like the controller is going into thermal shutdown.
Going slow for a long period of time (30 minutes) with a heavy load (500 pounds) on oversized tires (22") will do that.

What drive system do you have, Series or DCS? I assume its a series, because I don't have the run/tow switch.
(If it has a Run/Tow switch, it's a DCS)

What controller do you have, stock or aftermarket? Stock

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You say it has only been a week since the batteries were charged.
Does that mean the DPI charge has been disconnected from the cart for a week? Yes
If so, you are not using the DPI charger properly.
In a nutshell, if the cart is not moving, the DPI charger ought to be plugged into it. OK, wasn't sure if it should be left to run constantly or not.

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A cart with an electronic speed controller should be more efficient than a resistor cart, but if the oversized tires are the low pressure type, it might not be.
What is the max inflation pressure stamped on the sidewall of your tires?
If it is below 10 PSI, they are likely to be amp-hogs. They call for about 8 PSI, but Im running 16 PSI to try to cut down on the resistance, and aid in the weight carrying capability. I specifically bought the 6 ply tires so that I could run them at higher pressure without worrying too much about puncturing them offroad.

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Your voltage readings don't sound right.
The Marathon charger should have charged the battery pack into the 44 to 46 Volt range before it shutoff and after the pack rested for 12 hours, the voltage should have been about 38.2V. At 24 hours, they should have been slightly lower.
Lead-Acid batteries typically self-discharge at about 1% SoC per day. It very well could be. Im just going off memory, with a casual glance at the meter. I will pay closer attention to it next time I get on it. The last time I checked with my handheld meter, the digital meter on the cart was pretty accurate, but its been a while since I checked it. I will recheck it with the handheld meter to see whats going on.
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What Make/Model batteries do you have? Energizers from Sams. I know they aren't the best, but its what I could afford at the time. Next time Im gonna bite the bullet for Trojans, but Im gonna run these until they are dead before I replace them.
The DPI comes with Mode-2 selected (Trojan Battery). According to the manual, there are 4 settings, and I am using the one for Exide batteries, as suggested by my battery manufacturer. Since Energizers aren't listed in my manual, I called the manufacturer to see which of the batteries listed in the manual that my batteries were most like. They said the Exides were probably the closest match. Should I change the charge mode to another setting?

In that mode, it stays in the bulk charge phase (constant current) until the pack voltage reaches 42.3V, then switches to absorption charge phase (constant Voltage) until the current flow drops to a predetermined rate of change, then switches to the finish phase until the change in voltage over the change in time (dV/dT) meets a predetermine rate. The pack voltage may reach as high as 50.2V, but usually doesn't get much beyond 46V.

When the regular charge cycle terminates, the charger goes into the Float charge mode and the voltage is maintained at 39.4V (in Mode-2).

If you are not getting voltage readings similar to what I have mentioned, there is an issue with your voltmeter, your battery pack or the DPI charger.

Entered my responses in red. Let me know what you think.

[JohnnieB]

Originally Posted by tyhuck

Entered my responses in red. Let me know what you think.

You loose about 20% of the available torque with 22" tires, so the motor has to draw more amps to move the cart and the stock controller is very likely overheating.

If you are also running stock (6Ga) cables, they might be overheating also. (Ought to be at least 4Ga cables.)

When the stock (275A) controller gives up the ghost, replace it with a 400A or larger.
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Whatever mode the battery manufacture says is the right one, is the one to use.

Leave the DPI charger connected when not using cart. That way you will start each trip with fully charged batteries, and they will last longer before they need to be replaced.

[tyhuck]

Im running 2g cables, and they run as cool as cucumbers.

Is it possible to replace the controller with one capable of handling 48v? I dont know when or if I will ever get to the 48v conversion, but it would be nice to have that option after replacing parts, rather than having to replace it again when I do the conversion.

Clear as mud?

[Olman]

Originally Posted by tyhuck

Im running 2g cables, and they run as cool as cucumbers.

Is it possible to replace the controller with one capable of handling 48v? I dont know when or if I will ever get to the 48v conversion, but it would be nice to have that option after replacing parts, rather than having to replace it again when I do the conversion.

Clear as mud?

I think JohnnieB is on the money about your controller going into thermal shutdown. It happened to me with stock controller, speed motor, big load, and going slow around the campground on my old series EZGO. Changed to 500 amp controller and never had the problem again. Yes, almost all aftermarket controllers larger than stock are rated for 48 volts. If I were you, I would contact ScottyB at Carts Unlimited and discuss your needs with him. He will advise you on your upgrade needs.

[JohnnieB]

Originally Posted by tyhuck

Im running 2g cables, and they run as cool as cucumbers.

Is it possible to replace the controller with one capable of handling 48v? I dont know when or if I will ever get to the 48v conversion, but it would be nice to have that option after replacing parts, rather than having to replace it again when I do the conversion.

Clear as mud?

2Ga cables was my first upgrade also.

There are two things in the drive system that are, or at least might be, voltage specific, controller and solenoid. (Plus the battery charger, but that isn't part of the drive system)

Some, but not all, controllers work from 36V to 48V, but there is only one solenoid that I know of that does and that is the Super-Duty one that Scottyb sells.

Bottom of page in this link: http://www.cartsunlimited.net/Custom_Options.html

[tyhuck]

Yeah, I know Scotty's site well, and to be quite honest, he's probably tired of me warting him. I've always wanted to do upgrade to 48v, but just never can seem to scrape up enough extra money to get it done. I was always planning on going with the pkg. 485, so now that I realize it can be upgraded on the 36v system I might go that route and slowly build the system to handle the 48v. Then all I would have to do is wait out the batteries and as long as those are the last piece of the puzzle to go in, it might be a doable upgrade. Now all I have to do is sell some knives to pay off the initial rebuild of my cart, and scrape up the money to get the new controller.

On a related note, would the F/R cam switch be able to be run on the new controller, or will that have to be upgraded to a reversing contactor setup?

[kernal]

Thats what I did. Wires first. Then HD switch cam, mostly as a precaution because I did't seem to be stressing mine. Eventually Alltrax SPM (400amp), 36-48 solenoid with 36v appropriate resister. Ran about a year like that, then when the batteries worried me I got a six pack of 8v's, a 48v DPI charger and appropriate resister. Changed the character of the cart completely. Should have done this years ago.
SPM controller was plug n play. When I jumped to 48v I just changed the batteries and the resister. Plugged in the new DPI and job complete.

Keep in mind the 8v batteries have the connections on the same side so you will have to change the 5 wires connecting the batteries.

[yurtle]

I have an Altrax 4855, which is a series controller. It can run on 36 - 48 volts. I have eight 6 volt batteries, and have been running the HD FNR with no issues. I bought the cam, but either I failed to thoroughly tighten the center nut, or the rest of the FNR wasn't up to the task, so I replaced the rest and have had no problems ever since. I considered a reversing contactor, even though ScottyB wasn't offering them at the time, but ended up modifying my FNR, moving the controller and solenoid, in order to make room.

To answer your question, it depends on how you plan on achieving 48 volts. A reversing contactor would have been easier than what I did.