jamis

Remember that the system will not let the Depth Of Discharge (DOD) exceed about 30% (down to 36 volts) before it shuts the mower down. So if you run the charge down to 50% on the meter, the real DOD is about 15%.

This 100%/70% display is a common issue with the Ryobi ZTs. Contact Ryobi at the number on the label under the seat. Also have the model number, manufacturer number, and the serial number from the label handy when you finally get through to a support person. Some users have had their meters replaced under warranty, with mixed results. The Ryobi instrumentation on their mowers has been sketchy since they came out. Better instrumentation would have driven the cost up, so we live with it. I have been measuring the pack voltage at the beginning and end of each usage ever since I discovered the weakness in the meter. The bottom two contacts in the charging port are positive and negative. I started using a digital volt meter, and switched to an onboard volt meter plugged into the charging port, and just modified the meter on my RM480e to display volts, percentage remaining, and hours. The beginning voltage should be above 52 volts at the end of the charging cycle, but the batteries will self discharge a bit just sitting. After nearly three years, my batteries will be around 51 volts a week after a full charge cycle.

Great news Kurt. Hopefully it's fixed and you have good performanc with it for a long time. Today, I ran my RM480e longer than I ever have in the 35 months I've owned it. I mowed for 1.5 hours non-stop, used 4.7 volts of the pack and the meter showed 42% of the charge used. Not bad for a mower that's almost 3 years old and supposed to run for 2 hours.

I was just reviewing the Ryobi Troubleshooting manual for these mowers and there is nothing in the manual concerning testing the battery pack. The procedures start with testing the main fuse and continues on through the remainder of the system and its components. I have no idea why (and I don't expect Ryobi to explain it) the battery pack is left out of the process, but over the years, the preponderance of problems reported publicly have been with reduced run times and there is nothing in the manual to address it. Probably why the service centers don't know what to do with it. There are four RM480s on my street of 16 homes with a fifth coming and the nearby (1.5 miles) service center hasn't touched one since they came out in 2017. A failing battery can fully charge and then quickly discharge under load and cause reduced run times until it fails completely and leaves the mower immobile. Anyway, the first step to do if your run time has degraded is the following: 1. Pull the battery tray per the steps outlined in the owner's manual and don't forget to disconnect the thin black thermister wire at the back of the pack prior to pulling the tray out. You will need an 11 1/2" high support capable of supporting 200+ pounds. 2. Disconnect all battery wiring from the batteries recording how they were connected. 3. Individually charge the batteries with an automotive style 12 volt charger, preferably one with a deep cycle setting. Pay attention to the charge times as a failing battery can take longer to reach full charge. 4. Load test each fully charged battery. I took mine to a local battery shop for this. 5. If all test good, go on to other test procedures. If one or more test bad, call Ryobi for assistance in sourcing replacements. Don't forget to have all of the numbers on the label under the seat handy for reference to the support person.

AFAIK, the AUX position of the key switch has never worked on these mowers. According to the troubleshooting manual and my mower, there is nothing connected to the AUX lug on the bottom of the switch. Run time is going to be affected by the ability of all of the batteries to hold a charge under load. It only takes one of the four batteries to bring the system down. Since the system shuts down when the pack voltage drops to 36 volts, if one battery fails to hold a charge under load, you can see reduced run times. Therefore, measuring the voltage at the beginning and the end of any usage will help you understand what's going on. My 34 month old batteries can sit for a week or more without needing a maintenance charge this summer, but they will still mow for over an hour and a half before getting into the red zone. My batteries have 195 charge cycles on them also. It's really too bad Ryobi decided not to utilize the voltage and percentage functions of the BLM. The information would be most useful for owners.

I can't explain the sudden backing up issue. Are you sure you didn't hit the F-N-R switch by accident reaching for the deck motor switch? Did the mower beep when the deck motors shut down? The system can be a bit flakey. I recently ran my 34 month old RM480e down to a flashing red bar and a solid red bar while mowing. No beeping and the deck motors kept running. I shut the deck motors off and drove the 500+ feet back to the charger. The pack voltage was 47.2 volts. I simply don't trust the factory instrumentation and record usage with a spreadsheet.

The system is designed to shut the mower down when the pack voltage reaches 36 volts. This is to keep the routine depth of Discharge (DOD) at 30% or less. This maximizes the number of charge cycles the batteries can deliver (1,500-1,700). The BLM is notoriously inaccurate and Ryobi won't say how it works, so measuring the pack voltage may be the only way to see what is going on. I had one of the batteries fail at 11 months to be able to hold a charge under load. Run time had been degrading shortly before failing. Ryobi said to pull the battery tray, disconnect the battery wiring, individually charge the batteries, and load test each. I took mine to a local battery shop for the load testing. I would bet measuring the pack voltage when the deck motors shut down would be a first step at showing a failing battery. I measure pack voltage at the beginning of each use and at the end just before plugging the mower into the charger. You can measure the pack voltage using the bottom two contacts in the charging port with a volt meter. Voltage right after finishing a charge cycle should be north of 52 volts. I use a watt meter ($30) to record charge cycles and can see if the system is holding a charge between uses.

I was clued into a YouTube video by member John31224 that covers a modification to the RM480 display module that allows the meter to switch through the three modes of display, Volts, Percentage of Charge, and Hours Run. The video is found by googling "Ryobi 480e riding mower battery indicator mod". It is a simple and inexpensive addition and makes operating the mower more informative. It adds a momentary push button to the console. Mine mounted in the seventh bolt hole between the key switch and the meter. The video shows the three displays.

One step at a time. I didn't realize early on how complex these machines are. The troubleshooting manuals are so worthwhile.

If both levers are not working, I'm wondering if it's the drive as there are two, one for each rear wheel? I wonder if it's something feeding both controllers? Maybe the troubleshooting manual will offer a process to check the power feed to the control lever mechanisms? Just SWAGing here.

The 12 beeps is confounding since it's not documented in the manual. If it beeps exactly 12 times each time, that's a real question for Ryobi to address. The testing procedure listed in the troubleshooting manual should be the same for the ZTs.

Kurt: PM'd you with some troubleshooting documentation. Don't know if I should make it public, hence the PM. Hoping it might help.

According to the manual, turn the key off, open the levers, turn the key on, and close the levers in neutral position. The beeping gives me pause. Not sure what you mean by clamped off, but I wonder if the switch has become defective somehow. My neighbor had issue with his as it kept popping out of the latched position. I have the seat switch test procedure on my PC and I'll look it up later. I wonder if the parking brake switch is amuck and causing the problem.

1. When it won't move forward, will it move in reverse? 2. Problem is with both levers? 3. What happens if the levers are moved out and back in? Required to reset the system after turning the key to on. 4. Any difference in high or low speed settings? 5. Beeping is most likely due to the seat safety switch not being triggered by the operator's weight. 5. Call the Ryobi support number on the label under the seat and have all of the other numbers available for the support person.

Thanks to John31224, I have just learned that the headlights on the RM480s are 12 volt powered, so the 48 volt DC to 12 volt DC converter on the mower is what is used for driving the headlights, backup beeper and the USB port. Yes, the USB port delivers 5 volts, but it is driven by 12 volts. I would expect the ZT540 to be set up the same way. Disconnect one of the headlights at the connector by the mount and measure the voltage with a digital meter with the mower switched on and the headlight switch depressed.

The repair sheet .pdf is downloadable from the Ryobi web site page for your model. it isn't really detailed enough for what you want though, just exploded parts diagrams and part numbers. My neighbor tapped into his RM480ex system by buying the connectors for the main battery connectors off the internet and then using the "48" volt current to power things like a high mount LED headlight and other accessories. He added a module to step the 48 volts down to 12 volts. This way no modification to the Ryobi system and it can all be easily removed. His mower will soon be out of warranty, so he's not concerned. These systems have a 12 volt controller, but it's not tappable that I know of and I don't really know what it's used for in the system.

Would you be willing to email the .pdf to me if I send you my email address? Would you be so kind to post a picture of the failed area?

The .pdf I have from the Ryobi web site is only 29 pages. Would love to see what they sent you. What is the name of the person that has been helping you?

Do you have the Repair Sheets document downloaded? It is available on the Ryobi web site pages for your mower as a .pdf file. Sounds like the batteries are fully charged though.

John: First thing I'd check is the master 125 amp. fuse under the seat. I have an onboard voltmeter that plugs into the charging port. No issues and I've even run with it plugged into the port. I have a plug from an incorrect charger Ryobi sent me.

Very curious as to exactly what brand and model batteries the store is supplying. The reason I ask is Ryobi specifies only the Leoch LPC12 batteries are to be used in these mowers because the SC-48 charger is set up for them. I have only heard of one user that has used a different brand of battery, but has not shared his results yet. The batteries he used have about half the stated charge cycles of the Leoch batteries and they were more expensive than the LPC12s. I look forward to see your results.

The bottom two contacts are the + & - of the system. The top contact is the battery temperature lead to the charger. I used a multimeter for quite some time. The spare charger plug is from a charger Ryobi sent me when I had a failing battery. The first support person I talked to said it was a bad charger with no troubleshooting. The charger they sent me was the wrong p/n and I was told not to use it, and not to return it either. The plug and cord were then available to use with the voltmeter.

A load test is definitely in order, just to see if any were damaged. I had one battery fail at 11 months and it wouldn't support any sort of load, even though it would take a charge albeit very slowly compared to the others. The Ryobi charger would not charge the pack and displayed a low voltage error (2 red blinks on the charger LED). The replacement battery made the mower run better than new which told me the failed battery was weak from the first run. Good luck

jefe: how long was the power out? Long enough to drop the pack voltage below 36 volts? The Ryobi system will not charge the pack if it falls below 36 volts. Leoch states these batteries can self discharge for up to six months before needing a maintenance charge. What is the individual battery voltage right off the charger? Should be at least 13.2 volts by my experience. Which LPC12 battery, 75 ahr or 100 ahr? Leoch doesn't state CCAs. Google "leoch lpc12-75.pdf" or "leoch lpc12-100.pdf" to see their data sheet. Ryobi only advised me to load test them, which I did by taking them to a local battery shop. They tested all four of them for free.

Ryobi specifies using only the Leoch LPC12-75 batteries in these mowers. The charger is specially set up Delta-Q SC-48 charger for these batteries. What was the blink code the charger was displaying? The mower will not run if the charger is plugged in. The system will not run if the battery pack voltage is less than 36 volts. The batteries should charge to 13.2 volts max. when properly charges. The pack voltage of my 33 month mower is usually 52.4 volts right after charging. Call Ryobi for help. The mower is warranted for 3 years even if the batteries are only warranted for a year.