jamis

Apparently, the Mighty Max SLA/AGM batteries sold by HD work in these mowers. My neighbor ordered one of the 100 ahr. Leoch batteries from HD three weeks ago and received it within days. It restored his mower's performance to like new.

FWIW, as the batteries in my RM480e age from use & charging, I'm documenting an increase in the cost per hour of use at $0.01 per hour each year. In other words, it now costs $0.04 per hour more to run my mower than it did the first year. Since everyone uses their mower differently and each use can have different factors, this is the one measurement that I think reflects how to measure the battery aging process. As of today, the cost per hour is at $0.258. By comparison, my neighbor's Toro V-Twin rider uses a gallon of gas per hour and the current price of 87E10 is $4.799/gal.

The battery covers are for dust protection, so it's your choice. If it were mine, I'd put them on. Glad to hear the new battery works.

Just some thoughts on the instrumentation of these mowers. After 45 months, 342 charges, 124 hours of use, I have come to the conclusion that the number of variances in mowing and the discharge characteristics of the batteries makes the meters pretty much inconsistent. Using my spreadsheet data, I grouped all of the runs that used 7 to 9 bars on the BLM. One 8 bar mow of 1.4 hrs required 3,610 watts to recharge. A year later an 8 bar mow of 1.3 hrs. required 3,270 watts. This was the same sq.ft., just 6 min. difference in time. This week a 9 bar mow of 1.6 hrs required 3,330 watts. Last year a 9 bar mow of 1.7 hrs. required 4,050 watts. Again, the same sq.ft. The voltage drop of these runs ranged from 3.6 volts to 8.3 volts. the only thing I have been able to determine from the data is that the average cost per use has been increasing by about $0.02 each year, and the cost per hour has been increasing about $0.03 per hour each year. Overall cost per hour for the 45 months is $0.256 per hour. I have been paying $0.13 per KWH for electricity. I have spent a total of $31.86 for electricity for runs over the 45 months. Add in winter storage costs and the total cost of electricity is $37.03 This tells me that my batteries are aging slowly, but still have plenty of life left.

What is the pack voltage at the charge port when the mower will not move under its own power? My mower will shut the deck motors off at around 46 +- volts but still move. I've never run it down to where the drive motor won't run though.

As to the CCA question, I can only say that Ryobi's troubleshooting process is to run a load test on the batteries to see what the condition is. The $40 load tester my neighbor bought, and the commercial load tester the local battery shop used, both measured voltage drop under load vs time to determine the health of the batteries. I'm no expert, but if that's what the manufacturer says is to be done, that's what I'll do. I also find it interesting that both Leoch and MM deep discharge style batteries don't list the CCA of these batteries. I do know the Leoch batteries are used in wind farms, solar arrays, UPS installations, and mobility devices where CCAs are not important.

Glenn: Yes, I built the dolly to be the same height as the tray slide. Ryobi's advice for not having an adjustable height dolly was vary the height of the tray by adjusting the rear tire pressure to bring the two into alignment. I really don't know about the MM batteries as I've not seen the results of anyone using them with the Ryobi charger. They appear to be very much like the LPC12s though. As for how many batteries to replace, it's up to the owner. My neighbor has a RM480ex with over 600 hours of run time and he just replaced one battery two weeks ago with an LPC12-100 from HD. He's been gone on a trip so we haven't seen what the change has done for his run time yet.

I find that the 70% display is so common amongst users reporting the display issue. Why is it always 70% and not some other number? That makes me think it's a problem with the instrumentation and not always the batteries. Made even more confusing with no explanation from Ryobi other than replacing the meter.

I'm very interested in seeing how the MM battery works with the Leoch units. Now that HD is carrying the LPC12s again, I'd be tempted to buy one of those as a replacement. Interesting that the two batteries only differ by $19 in price.

You just replicated the same sort of test the local battery shop did with their professional equipment. Their equipment had variable resistance to identify the point where the fail was occurring. I would say you have identified the one battery in your pack that has a weak cell. I predict it will continue to get weaker until it fails completely with an open cell or a dead short cell, or at least to the point where any load will drop the voltage to the point where the mower system cannot run or charge. I used the local battery shop because I've been buying car batteries there for decades (5 year replacement warranty) and they have rebuilt numerous cordless tool battery packs over the years, so I trust them. My neighbor's load tester displays the voltage of the battery and then shows the dropoff when the fixed resistance is switched in. Their documentation states a good battery should hold voltage for ten seconds.

Do you have a battery shop in town? I took mine to them and they tested them for free. I offered to pay for their time (about 10 min.) to test all four, but they refused as they said it was what they do. They even rolled the tester out to my car and did the test with the batteries in the trunk.

Some additional thoughts on the RM480 BLM. There are two electrical connections to the meter. After startup, the meter shows the cumulative hours the key switch has been turned on (unless it resets itself to zero). There is a third contact on the BLM that has no wire going to it. If you jumper that contact with a normally open push button switch to one of the other leads, you can step the digital display through volts, % charge, and hours run. Some BLMs have a push button on the underside that will step through the displays. I have recorded these numbers along with the recharge wattage and the amps. used and the number bars out on the BLM. I have not been able to correlate any of these numbers to figure out what the BLM uses to display the information it shows. The % display and the bars out are roughly equivalent, but volts, watts, and amps. don't tally out from run to run. I once ran the charge down to 9% and one bar left. The voltage was 42.2 volts from a beginning voltage of 50.5 volts. Another run showed 8 bars out and 23% charge left with 50.7 volts going down to 46.5 volts. Both of these runs ran until the deck motors shut off. The best I can figure out is the BLM uses time and voltage to calculate what it shows.

My neighbor with a RM 480ex was experiencing reduced run times this spring and he has at least twice the number of charge cycles my mower has because he mows twice the sq.ft. that I do and he plows snow with it. His mower is a couple of months newer than mine. He replaced one battery last week after testing his batteries with a $40 100 amp. tester he bought on line. He's gone this week and I'll have to wait till he returns to get the exact make & model. BTW, there are now five of these mowers on our street of 16 homes. Two are nearly 4 years old, two are two years old, and one is new this spring. Most assuredly the charging system does not trickle charge. I have read that trickle charging SLA/AGM batteries is bad for their lifespan. I have spent a lot of time on the Battery University website trying to learn about these batteries. The 70% charge issue is just bad instrumentation from what I've read. Even a new BLM has not fixed the issue in some cases. A weak cell will indeed bleed down and cause a confusing reading and also more frequent charge cycles. When I individually charged each battery as part of Ryobi's troubleshooting proceedure, the weak battery took far longer to fully charge. That's why I went to measuring things externally and using a spreadsheet to track battery performance.

The 30% DOD came from Ryobi when I had a battery fail at 11 months. I have my charger plugged into a Poniie P2000 watt meter so I can see when the system charges the system. When the mower was new, it would charge the batteries about 4-5 weeks apart and use 400-600 watts to do the maintenance charge. Last winter (the fourth) it started doing a maintenance charge every day of 100 watts per charge. The system has been doing a charge when the pack voltage drops below 50 volts. Re-plugging a fully charged system will boost the pack voltage somewhat. After 340 charges, I suspect the batteries are getting worn, but I can still mow for 2 hrs before blade shutdown. I confess I still don't understand how these SLA/AGM batteries really work, despite all of the data collected and battery research I've done. I took my batteries to a battery shop for testing since they have a commercial unit. I would guess the issue with the charge returning after sitting speaks to a weak cell in one battery. This is what mine did when the run time dropped off. Eventually, The pack charge would drop below 36 volts and the charger would not even attempt to charge the pack. Load testing showed one battery would not hold a charge under load. As soon as a load was applied to the fully charged battery, voltage would fall off.

Actually, Delta Q SC-48 smart charger used in these Ryobi systems puts out much more than 48 volts. I have measured over 54 pack volts after charging my RM480e. My neighbor measured just over 61 pack volts on his RM480ex this week when he installed a new LPC12-100 battery to replace one that was failing a load test.

I have yet to see in print anywhere that the electronics and the charger in the Ryobi SLA/AGM mowers will work with lithium technology. Even Ryobi states they won't. I have seen someone spending more than $1,700 to convert one of these to work with lithium technology. New controllers and charger, plus batteries. You could buy two sets of SLA/AGM batteries for that. I have yet to see any lithium packs with more charge cycles than the Leoch LPC12s. Elon Musk has stated the current Tesla lithium packs are good for 1,600 charge cycles (300K-500K miles). Ego states their 56 volt lithium packs are good for 1,000 charges. The Leoch LPC12s are rated for 1,500-1,700 charges the way the Ryobi system manages them. How about selling your current Ryobi zero turn and buying one of the new Ryobi lithium zero turns if you just absolutely have to have to have a lithium powered mower?

I think my batteries have fully recovered from winter storage. My RM48oe is 45 months old, 177 mowings, 336 charge cycles, and 120 hours of run time. Today, I mowed 26,000 sq. ft. (.6 acre) of lawn non-stop for an hour and a half, ( lots of turns). The run used 3.4 volts and 58% of the usable charge and 6 bars on the BLM. The spring grass was pretty dense as the run used an average of 60 amps. and it took 3,030 watts ($0.36) to fully recharge the battery pack. This is inline with previous 1.5 hr. runs from the previous seasons. I think the batteries would have easily hit the 2 hr. run time specified for this mower. If fact, last year, I got a 2.5 hr. run from this set of batteries. It still costs less than $0.26/hr. to run. Compare that to $4.25/gal. 87E10.

My neighbor with a RM480ex just received his replacement Leoch LPC12-100 battery from HD. He load tested all four and only one failed. Won't be installed until this weekend. The new battery is on a charger to make sure it's up to full charge before assembling into the pack. This was Ryobi's advice when I had to replace a battery under warranty.

Definitely pull and test the batteries. No sense spending money on ones that are not needed.

Please let us know how the MM batteries work. They look like they have the same characteristics as the Leoch LPC12s. I have read of Canadian users using battery blankets to keep the pack warm in ubercold storage temps. Apparently, they make bigger blankets in the Great White North to keep engines comfortable.

HD also now has the 75 ahr. & 100 ahr. Leoch LPC12 batteries back in stock. These are the original equipment batteries supplied in the new mowers. https://www.homedepot.com/p/12-Volt-75-Ah-Sealed-Lead-Acid-Battery-for-Ryobi-38-in-Riding-Mowers-LPC12-75T6/319074199

Might want to think about drain & refill the transaxle if you do pull the batteries, even though Ryobi dropped the 100 hour requirement. Ryobi stated to me that you can use full synthetic gear lube in the unit.

Yesterday, my neighbor asked me to assist him with battery testing on his RM480ex. His mower is a couple of months newer than mine, but he uses his year round for snow plowing in the winter and mows more than twice what I do. His run times had fallen this spring to where he could only mow for about a half hour instead of two and a half. He had purchased a 100 amp. load tester rather than taking the batteries to a shop. We determined that one of the four batteries would not hold a charge for ten seconds under load and it took longer to charge fully than the others. He is going to order a replacement battery and see what happens. I had the same issue at 11 months and eventually the battery failed to where the charger would not even begin charging due to too low a voltage. The replacement battery fixed the problem for me. My mower is now 45 mos. old and my collected data is showing the battery performance is the same as when it was new after 330 charges.

You may not have to replace all of them. The owners manual shows how to remove the batteries. One weak cell can bring the system down. The batteries should be good for 1,500-1,700 charge cycles. A simple load test of each will show you what is going on. I took mine to a local battery shop for testing. I had one go bad at 11 months and a new battery replaced it. mower has been flawless for almost 45 months now. 370 charges, 160 hrs. of use. Ego 56 volt lithium packs are rated by Ego for 1,000 charges. This month, the cost of operation vs. a comparable ICE mower with pay for new batteries in my RM480e. The current cost of 87E10 gas makes my mower 16x less expensive to operate than an ICE mower.

Historically, the first few mows after winter storage, the batteries do not perform up to normal. Every spring, after the four month storage period, the first few mows are suboptimal. Then the batteries get used to being deeper discharged and things return to normal. This spring, after 370 charges, the batteries seem to be taking a bit longer to "wake up". However, the voltage drop per mow is about the same. I am also measuring that the winter storage charges are coming more often, but less wattage per charge. I suspect this is due to aging, but I don't think they are at the point of replacement yet. Only a load test would confirm and I'm not that concerned yet. I've been mowing all April in 50 degree temps., as have been the four other owners on my street, with no issues. The mowers range from brand new to four years old.