Overheating issue RXV

NoBones

2009 RXV lifted bought used in 2012., new batteries 2 years ago.
Cart ran great for a coupla years. Replaced batteries and ran just fine. Then, the cart would stop abruptly for no apparent reason. I noted a cooling coil just behind the solenoid. When the cart stopped the fins of the cooling gizmo were HOT, HOT. After cooling off the cart ran fine. The overheating became more and more frequent and after shorter run times. Sometimes only after < 100 yards. Now cart is dead. No click in solenoid.

Any thoughts on the overheating and did that possibly burn up the solenoid?

BGW

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usgicollector

Do you have excess to a Danaher handheld programmer?

usgicollector

See if this helps any.

Attached Files

RXV-FSIP Handset-Manual.pdf (923.7 KB, 0 views)

NoBones

Houston, we've got problems!
In an earlier thread I had worked thru some really dead battery issues. That is resolved. Batteries completely charged.

I looked at the Handset manual USGI sent me but I was not certain how to interpret it. I googled 'troubleshooting solenoids' and walked thru the first check. The solenoid does not click. I looked on the solenoid label which says "36v/ cont". But I've got a 4 x 12V = 48 volt battery pack!!!
Reflecting back, my overheating problem began precisely when I bought the 4 new 12 volt batteries. Shouldn't I have a "48V/ cont" solenoid not a 36V? Could the overheating be caused by 48V being run thru a 36V solenoid? Did some moron switch the old 8 volt batteries for new 12 volt?

Please make me feel smart.

usgicollector

No your ok that the way that cart came. Don't go replacing it with a 48v one.

kernal

The RXV solenoid is activated with 36v. I believe after activation the controller lowers voltage to 24v to keep the contact closed for cooler solenoid operation.

Do not assume anything on the RXV operates the same as any other cart. Poking around in the electronics without understanding how the cart works will likely make you sad. $$$

BTW, most RXV's come from the factory with 12v batteries. 8v batteries can be installed using a different rack. Not technically difficult. It's a better cart with the 8v's IMO.

NoBones

I understand the complexity of the RXV. I regret buying one. I am trying to understand the complexity of the electronics. My cart overheats and it started with the new 12v batteries. The heatsink is there for a purpose of cooling something. When it overheats it shuts down the whole system. What does it cool?

I suspect the controller may be bad. I am in hopes it is something simpler and less expensive.

BTW kernal, that is one fine dawg you have! We are Labrador Retriever folks here. 2 Chocks. and a Whitey: Ruff, Rowdy and Rascal. Next one I'll name Woof!

rngilliland

If you mean the cylinder with the spiral fins on it that is the resistor. I think it is only used to burn off excess power that can't be returned to the batteries when you are braking or coasting. I don't think it being hot would mean the cart is overheating. The controller has fins on the back for cooling. The are below the resistor and are part of the controller.

I would check the fuses on the plastic panel with the run tow switch. Also make sure your batteries are fully charged.

In my experience with my RXV and a few friends RXV's the slowing down or suddenly stopping is the parking brake failing. There is usually a burned wiring smell but not always.

You'll have to figure out the solenoid problem first but my guess is the original problem was the brake. The best prices I have found are on Ebay. Only use an OEM brake. Follow the manual or search this site for instructions to replace the brake.

JohnnieB

In your first post in this thread you stated your 2009 RXV is lifted, so I presume it has tires taller than stock and that is very likely the root cause of the overheating issues.

The RXV drive system is specifically designed to turn 18" tall tires thru a transaxle with a 16.99:1 gear ratio for a final drive ratio of 22.65:1. The regenerative braking that is used to stop cart is also designed to operate with a 22.65: final drive ratio. Installing taller tires changes the final drive ratio and takes the drive/braking system out of its designed operating envelope. There is some tolerance, but 20" tall tires is approaching the limit and no lift is needed for 20" tires.

It takes more torque to turn taller tires and due to the change in the final drive ration cause by the longer radius of the taller tire, less torque is available where rubber meets road and the motor is turning fewer RPMs for each tire revelation, so it is capable of drawing more amps and the net result is a higher average amp flow through the controller, which in turn causes more heat to be generated in the controller and if it is excessive, the controller shuts down.

The regenerative braking is less effective due to the change in the final drive ratio. I'm not sure of this, but I suspect you have to push the brake pedal harder to stop the cart from a given speed with tall tire than you have to with the tire height the braking system was designed to operate with, so more electrical energy has to be absorbed by the battery pack or the overflow resistor that gets so hot now.

The regen braking system uses the motor to convert the kinetic energy of the moving cart into electrical energy (changing it from a motor to a generator) which is either stored in the battery pack as chemical energy that can be reused to propel cart, or into a resistor that disperses it as heat to prevent the batteries from being overcharged if they are fully charged or close to it. With new batteries, the overflow resistor will be used more, so the big resistor in the cage getting hot after new batteries were installed is probably normal.

I don't know if the controller has been damaged by overheating, but I'm pretty sure the oversized tires are a major contributing factor to the overheating issues you are having.

NoBones

RE: Brakes. I had a parking brake problem before the batteries went bad. I replaced the parking brake with what appeared to be a non-OEM part. Ran fine for a few months. Then I replaced the batteries w/ 4 new 12 volters. Then I started having shut-down and stop issues again identical to that of the past. More and more frequent and at shorter run times.

Presently the Batteries are fully charged. The 10amp fuse on the Run/Tow box is functional. There is no click from the solenoid as I depress the accelerator.

Additionally (and this may be the real issue), When I switch from Run to Tow at the Run/Tow box the parking brake remains engaged. Could the parking brake be the culprit?

There is an advertised Heavy Duty "OEM upgrade" RXV parking brake on Amazon professing to keep the brake cooler, preventing cracking and premature failure. Your thoughts on that?

JohnnieB: I understand what you are saying. However, I had no problems for 3 years after I installed the 22" tires (they in reality are a hair over 20" what-with the 10# air I inflated them with). Very rocky terrain here in Central Texas mandates low air pressure in tires. Terrain here at the ranch (and wife screaming "Slow down! You'll run over the dogs!) also mandates very slow speeds <10mph which means fewer amps fed thru system? Your thoughts? Do you wear that hat all the time?