2014 EZ GO RXV e-brake and batteries

[madeemer]

I have a 2014 EZGO RXV and havne't maintained it well probably according to most people. I know how to check batteries and fill and tighten wires on battery terminals etc. But the batteries were at least 4 years old and weren't doing well and I am guess one of the batteries or more had a bad cell. I didn't take them to get tested as I just let it ride figuring when they stop working I'd go lithium this year. Well I was riding in it when I heard a pop under the seat luckily I was not going full speed which is 23-24mph according to Waze app and was only going about 15 mph and let off the gas right when it popped. Well the e-brake kicked in and we skidded to a stop. Well the 2nd battery in the series of 4 lead acid had the battery terminal melt and the bolt popped off. Well that sucked I had to touch the red wire back to the melted terminal to get the e-brake off and push it back to my house. Now I can't get the e-brake off even following the instructions on the brake release button under the seat of what to do when you loose power. I thought getting this kind of cart would be safer but this is actually less safe to me in some respects. Any work around get the brake to release again?

Also, I need new batteries and hate lead acid and will go lithium. Local dealer who I got the cart from was lecturing me on not doing maintenance, they were not wrong but I didn't need the lady lecturing me. They previously installed Roypow but now do ECO 48V battery. I asked her about voltage and brake locking up with lithium and she said it only happens to people who don't know what they are doing with also rubbed me the wrong way. I have read many forums on here before I finally joined. I can do basic wiring but I read all sorts of brake bypass wiring diagrams and that is beyond me. Debating whether to pay them a $4200 for batteries and differential oil change. Can I buy a battery myself and install it and is it safe? That local dealer said they couldn't get me a battery until mid June. Only a month but would prefer to do something sooner. Suggestions or just have my stupid butt take it to dealer? I see Roypow kit can be purchased online from 18650batterystore.com or the big batterystore who say they are authorized dealers where as ECO the brand my local cart store sells now isn't available online only at dealers. sorry for the long first post.

[pjr202]

Originally Posted by madeemer

I have a 2014 EZGO RXV and havne't maintained it well probably according to most people. I know how to check batteries and fill and tighten wires on battery terminals etc. But the batteries were at least 4 years old and weren't doing well and I am guess one of the batteries or more had a bad cell. I didn't take them to get tested as I just let it ride figuring when they stop working I'd go lithium this year. Well I was riding in it when I heard a pop under the seat luckily I was not going full speed which is 23-24mph according to Waze app and was only going about 15 mph and let off the gas right when it popped. Well the e-brake kicked in and we skidded to a stop. Well the 2nd battery in the series of 4 lead acid had the battery terminal melt and the bolt popped off. Well that sucked I had to touch the red wire back to the melted terminal to get the e-brake off and push it back to my house. Now I can't get the e-brake off even following the instructions on the brake release button under the seat of what to do when you loose power. I thought getting this kind of cart would be safer but this is actually less safe to me in some respects. Any work around get the brake to release again?

Also, I need new batteries and hate lead acid and will go lithium. Local dealer who I got the cart from was lecturing me on not doing maintenance, they were not wrong but I didn't need the lady lecturing me. They previously installed Roypow but now do ECO 48V battery. I asked her about voltage and brake locking up with lithium and she said it only happens to people who don't know what they are doing with also rubbed me the wrong way. I have read many forums on here before I finally joined. I can do basic wiring but I read all sorts of brake bypass wiring diagrams and that is beyond me. Debating whether to pay them a $4200 for batteries and differential oil change. Can I buy a battery myself and install it and is it safe? That local dealer said they couldn't get me a battery until mid June. Only a month but would prefer to do something sooner. Suggestions or just have my stupid butt take it to dealer? I see Roypow kit can be purchased online from 18650batterystore.com or the big batterystore who say they are authorized dealers where as ECO the brand my local cart store sells now isn't available online only at dealers. sorry for the long first post.

Not 100% sure I understand your problem, but the solenoid in my 2017 RXV took a crap right in the middle of the road while my 13 year old was driving it. Scared me to death when she called me from a mile away (where she shouldn't have been) where the cart had just been sitting in the road. The tow switch would only get the cart to move about 1 foot before locking back up, so the guys that rescued her flipped the switch over and over until they could get it in their driveway.

It took a lot of searching, but I eventually found steps to fully unlock the brake. It's reversing two of the plugs on the panel where the tow switch is. This should be what you need to get rolling...literally.

https://www.youtube.com/watch?v=X8vZo6_iXcM

Also, while renting a U-Haul for an unrelated reason, I found out the battery store doing the U-Haul rental sells and installs golf cart batteries. It may behoove you to see if there are battery stores in your area that do the same thing. Could save you some cash vs the cart shop. Maybe not.

[Volt_Ampere]

The problem with RXV's and Lithium is that if your BMS interrupts power due to undervoltage or overcurrent, the $%^ brake just locks up at speed. Same thing happens if you have a solenoid failure. Dangerous especially if your cart is a fast one. I've seen it happen. (the solenoid failure case)

[ojo]

Remove the brake and take it apart, easy job. Check everything for any damage. You can measure the resistance of the brake coil also, should be ~ 25 ohms.

[Pat911]

@Madeemer, I would find another supplier. If I were spoken to in a condescending manner like that I would have walked out straight away.

When it comes to lithium, the main problem is in choosing the correct battery for your cart, not the installation. For your dealer to say that brake lockups with lithium only occur to people who don’t know what they are doing is just ignorant. You can choose the correct battery, install it perfectly, but if that battery has a fault, to maintain safety the BMS will do what it’s designed to do and cut power. That will cause a lock up on the RXV.

The backup circuits you talk about involve a second smaller battery that powers just the ebrake. I did get involved in that discussion and my recommendation was to power the ebrake directly from the main battery pack, bypassing the BMS so that in the event of a BMS shutdown, the ebrake remains powered. You can then coast to a stop. Safety is maintained as the ebrake takes very little current from the battery and you know there’s a battery problem that needs to be fixed as your cart will not move. The backup battery solution is needlessly complex and you must ensure that the backup battery remains charged.

For your cart I would choose a lithium battery wisely.

Cheers
Pat.

[Volt_Ampere]

There is a secondary safety problem though. Without power, there is no braking action with the motor and there are no mechanical brakes other than the one on the motor. At least that is my understanding of how the RXV works.

[Pat911]

I don’t own an RXV but from my understanding the brake is a seperate magnetic brake and is independent of the motor.

Power disengages the magnet, releasing the brake. Remove power and it locks up.

Edit: I get what you’re saying now Volt_Ampare, I think you’re right, the cart will have to coast to a stop and there will be no brakes to slow you down. No regen braking if the BMS has tripped.

[Volt_Ampere]

And that is why the mechanical brake was designed to lock up on power loss. That was much more unlikely to happen before the Lithium Battery BMS became available. It did happen to a buddy of mine several times with FLA batteries when his solenoid started failing. After almost getting thrown out of the cart twice, he asked me to look at his cart. I shot from the hip and had him order a replacement solenoid and that seemed to solve the problem for him.

[Pat911]

Yep, total power loss with FLA is very unlikely, whereas almost the norm with Lithium. Every user will likely experience it at least once, especially if other family members unknowingly run the battery down. Looks like the only totally safe Lithium conversion for a RXV will include a mechanical brake conversion as well.

[Volt_Ampere]

There are many RXV Lithium carts here. Probably the most popular model - and almost everyone in the past two years has gotten them with Lithium from the dealer. Not sure how their systems work - most are only 60AH batteries too. (Made by Samsung)