2011 RXV LiFePo Upgrade Taking Out Solenoids
 

I recently installed a set of four 12v 100ah Amazon LiFePo's in my 2011 RXV w/ a Danaher controller. Lifted with 22in. tires. I was told it had a speed upgrade when purchased and it will do 19-20mph. Otherwise it's all stock.

After the batteries and cables were swapped I went for the first test. 10 seconds in I got up to 15-20mph and the brake locked up skidding to a full stop. The 36v solenoid that came with the cart was dead and it cut the power to everything. Yes, 36v was in it for years with four Trojan 1275's.

Replaced with a fresh 48v generic solenoid recommended for an RXV of my year. Voltage readings were 52-53v at the solenoid. Giving it about 50% throttle on its test run, it dead.

Thinking it may be a quality issue, I went with a higher amperage White/Rodgers 48v 200/600 (WRS-586-120111). Same thing. Dies as soon as I give it 50% throttle. Solenoids are cool to the touch the entire time.

Do I need a bigger solenoid or a better controller to handle these batteries?

I appreciate any recommendations.

Re: 2011 RXV LiFePo Upgrade Taking Out Solenoids
 

Sorry to be the bearer of bad news but the problem is your batteries. They cannot produce the required current your cart is demanding and one of them is shutting down. Either that or your batteries aren't balanced and one of them is shutting down on low voltage, but my money is on insufficient amps. Did you also purchase a new lithium charger or are you using your old lead acid charger? You must use a lithium charger.

You should have purchased a 48v battery designed for high current use, not 4 x 12v batteries designed for RV/Solar use.

As you've already experienced, the RXV is one of the most dangerous carts to have a battery shutdown as the brakes will lock up. Another member here experienced a roll over in that exact situation so be careful.

Cheers
Pat.

Re: 2011 RXV LiFePo Upgrade Taking Out Solenoids
 

Pat911 is spot on. Your batteries are cutting out - it's not a solenoid failure. I don't know what batteries you actually have but I bet they can't handle the current demand and their BMS is cutting power!

Re: 2011 RXV LiFePo Upgrade Taking Out Solenoids
 

Your RXV uses a 36 volt solenoid. The controller regulates the voltage to the solenoid. It seems strange when you first see it but 36 volts is used to operate the solenoid. The voltage on the large terminals will be whatever the battery voltage is. On later models they did use a 48 volt one but all Danaher controllers use the 36 volt one. Ezgo part number 609428

Re: 2011 RXV LiFePo Upgrade Taking Out Solenoids
 

I apologize for my ignorance in the EV world. I worked on ICE vehicles my whole life and now being cast into batteries. The solenoids are fine. The original 36v solenoid made me suspect it blew under the load of the new super powered Lipos, lol.

I do have the LiFePo charger for them, but was wanting to test on the storage charge before I topped them off. The batteries are sitting at 13.11-13.17 currently.

What should I look for in a discharge rate for these batteries? The 4x 12v's I talked myself into have a continuous discharge rate of 100amps. Some of the single 48v packs spec 120amps continuous so I figure that was close enough.

Discussion for another thread, but I'm think the RXV brake is coming off soon. Looking at hydraulic disks for the front, but wondering what to do about a parking brake.

Thanks,
Don

Re: 2011 RXV LiFePo Upgrade Taking Out Solenoids
 

100A continuous is borderline for a cart, especially for a modified one like yours, but the main difference is in peak amps. A battery designed for traction motor (EV) use will also have a peak amps rating (e.g. 300A 10 seconds) and what this means us that the battery can supply 100A all day long (whilst they have charge) but can also supply up to 300A for up to 10 seconds. The peak amps is required for acceleration and hill climbing. Your batteries most likely cannot supply any current over the 100A rating.

I don’t know the current demand of the RXV but as a test, try accelerating away very slowly and see if the batteries remain “on”. This will reduce the current demand on them. Not a real solution but just a test.

Cheers
Pat.

Re: 2011 RXV LiFePo Upgrade Taking Out Solenoids
 

Before starting another thread, realize the following:

You can install an additional front disc brake on the RXV ( one of my favorites ), but you CAN'T remove any parts of the stock brake system! The main braking ( when you step on the pedal or lift your foot from the gas ) is done by regen direct in the motor ( counter current brake ). The additional electro magnetic disc brake at the end of the motor is mainly a parking brake, it'll engage in an emergency situation ( panic step on brake pedal or total voltage loss ) too.
On start up, the RXV controller is running a self test, with a faulty or missing em-brake the cart WON'T run.

Re: 2011 RXV LiFePo Upgrade Taking Out Solenoids
 

Sorry to say this to you, but it Sounds to me that you need to return the batteries you bought and buy a "real" golf cart battery pack. Eco, Roypow, etc. Easiest and less expensive solution.

Re: 2011 RXV LiFePo Upgrade Taking Out Solenoids
 

That is the consensus here but it doesn’t fix the fact that in its stock form, a lead acid RXV converted to lithium is dangerous, regardless of battery manufacturer.

Re: 2011 RXV LiFePo Upgrade Taking Out Solenoids
 

Sorry, off topic to original question...
But, what changes would be necessary to convert to lithium on RXV?