Ryobi battery riding lawn mower

[Eric S]

I do the same but for some reason forgot to blow the grass off the mower from the previous time.  I did clear it off last time and mowed again this past Monday and was able to get the entire yard done dropping from 100 to 80% charge.  Grass was dry and I leave it at 4”.  BTW, after clearing grass off from when the batteries dropped fast I plugged the mower in and they were showing Full Charge @ 100% in about 2 hours.  I’m going to chalk it up to the grass bunching up around the motor covers and causing the motors to get to hot and consume battery power.  

[jamis]

As I stated earlier, I replaced the OEM 75 ahr. batteries with Mighty Max 100 ahr. batteries. After 58 months, 160 hours of run time, and 2,082 charge cycles, the run time was down to about 45 minutes on a full charge.  One of the four other RM480 owners on my street that replaced his batteries last fall is associated with the local amateur ham radio club and he gave his old batteries to a member to use as battery backup storage with his solar array. I offered my old batteries to the club also and they are now part of someone's UPS system. The four old batteries were load tested by my neighbor and sure enough one of them was not able to hold a charge under his 100 ahr. tester. This is typical when these mowers lose their run time capability. Since my batteries were almost five years old, had over 2,000 charges (Leoch stated they should do 1,500-1,700), and had saved $685 in gas and maintenance costs; I went ahead and replaced all of them rather than just the one weak battery.

[Eric S]

With drought conditions here in Western Wisconsin my yard has become pretty dry and dormant as cool season grasses do.  We’ve had less than 1” of rain so far this month.  So for the time being the mower has been stored in the shed & plugged in.  We’re supposed to start getting rain this weekend then on & off over the next week or so.  We had a lot of snow this past winter which helped us get out of last year’s drought conditions but now we’re right back in it.  Even neighbors that run their sprinklers twice a day aren’t getting anywhere with the lack of rain.  
 

I ended up giving away my 4 original batteries to a coworker, who in turn gave them to his nephews to use at their off-grid cabin.  Good to know someone can still get some good use out of them.  

[jamis]

I have done over two dozen uses with the new batteries and the larger ahr. batteries are proving to be an improvement over the original 75 ahr. units. The lowered DOD is showing up. The cost per hour is also dropping. It used to cost $0.10-$0.11 to mow my lawn and now it costs $0.07-$0.08. I know it's a small difference, but it will add up.

[atebit]

So just purchased a RYRM8070 80V lawn tractor from HD today, should be delivered in a few days. Does anyone know of an aftermarket set of flip-up armrests or grab-handles?

[Eric S]

This will be my last post in this forum as I’ve decided to move on from my RM480ex mower.  As noted in my previous posts I replaced all 4 batteries May 22’ from the original OEM Leoch 100ah to Mighty Max 100 ah.  In the last three weeks the charge goes from 100 to 50% in about 1 hour of continuous run time, this happens when mowing in my front yard which does have a slight incline of a road ditch and my septic mound.  Because I’m past warranty on the batteries there’s no way Mighty Max will swap them out for new ones.  As in my previous posts, all four batteries were removed from the mower this past October and placed in my basement (68* F) and kept on individual 4ah charger/maintainers the entire winter which kept them in a state of change at 13.6 - 13.7 volts.  As Einstein said the definition of insanity is repeating the same thing but expecting a different outcome.  
I don’t believe Ryobi is to blame as the mower still cuts great and has held together well, I’m just not happy with battery life.  Doesn’t seem to matter which company it is.  Technology is getting better everyday, but 12v SLA deep cycle batteries are, in my opinion not the best option for this platform, however I’m not willing to fork out another $1K for Lithium batteries.  For me it’s back to gas.  I wish everyone the best of luck with your mowers.

 

r,

eric

 

[jamis]

Sorry to hear of your bad luck with the MM batteries. I replaced the Leoch 75 ahr. batteries with Mighty Max 100 ahr. batteries after 58 months. After 25 mows, many over an hour and a half, the pack is still performing like new. The BLM is off with percent and bars out.No matter how much I mow it always shows 100% and no bars out. My neighbor with a RM480ex and MM 100 ahr. batteries mows at least twice what I do and his batteries are still performing well. 

[EricL]

I also am gonna part w some observations inre to my 2021 54" 48v ZT.

1. I know I have had it easy compared to many of you.  Until today.
2. Glad I kept my 2005 50" Dixie Chopper.  My Ryobi 54" ZT basically just died; on full charge, mower moves and blades briefly come on, but that is followed by a loud beep and the blades cut off.  I hope it's just the batteries.
3. I really like the mower itself, but batteries have never been up to my task (on 4 acres, ~ 3-3.25 mowable).  In the best of times I got it done over 2 days.
4. In this my 3rd season -- @ 200 hrs -- it was a struggle to mow for more than 20-30 minutes.  Season 3 went from meh to $#!+ quickly.   Seemed once I got past 150 hours things went downhill and fell off a cliff as I approached 200 hr.  Today took the cake.  Maybe that's the normal lifespan of these batteries?
5. I have noticed that despite being fully charged, when I unplug and then plug it back in, it will often charge for hours.
6. To Ryobi's credit, they stood behind the batteries after I complained; the new ones they sent are on a maintenance charger and I'll swap those in the spring.  If u want more intel on the steps to get new batteries, lemme know.  I am not swapping them now cos I don't trust the Ryobi charger to properly overwinter them (see #5).
7. The BLM is not much use.  Rather, the mower sound gives it away when I'm about to lose the blades.  Sometimes its at 30%, others (like yesterday) at 60%.  Today it was at 100%.

I really, REALLY wanted this mower to work.  But it's clearly not there yet.  Not even close.  I hope that maybe some day I can convert it to Lithium or swap in a longer-lasting deep-cycle SLA battery.

 

In closing, you all have provided excellent intel thru your discussions here.  Thank you.

 

Best wishes,

E

[Brad S]

I've been following this forum for a few years now.  I have a Ryobi RM480E mower (purchased in 2018) and my original batteries lasted 5 seasons.  I experienced many of the same issues that others have described.  Early this year, I replaced the original batteries with the Mighty Max SLA 100ah batteries.  I had already purchased the new SLA batteries before I discovered YouTube videos showing how to upgrade the batteries to Lithium LiFePO4.  Since I had already committed to another set of SLA batteries, I thought maybe I could position myself better for a future Lithium upgrade and possibly get some benefit at the same time with my new SLA batteries.

 

So I purchased the suggested charger that can charge both SLA and Lithium batteries and I installed the suggested gauge that can also handle both battery types.  In doing so, I now know that my charger is recharging my SLA batteries after each mow because it has a display that shows me exactly what is happening, unlike the OEM Ryobi charger which I think many times was not really doing a recharge even though it was flashing green.  I also now have a gauge that shows me my current Amp Hours / Voltage / Capacity Percent that seems to be pretty accurate.  I probably spent less than $225 and the YouTube videos show what adaptations are necessary to make things work...they are not really difficult.  I chose to reuse the OEM charging plug to replace what came with the new charger so I can easily plug into the RM480E charging port...again pretty simple to accomplish.  The YouTube videos do a good job of explaining what needs to be done.

 

I don't have a long term use report, but after one cutting season, my new MM SLA 100Ah batteries still show 100% capacity.  I will see how the batteries look after they over-winter in a NC garage where temps are fairly moderate.

 

With Lithium batteries probably declining in price in the future and the possibility of me getting more than 5 seasons out of my current MM SLA batteries due to a "better" charger, I felt the extra expense at this point made sense instead of just continuing with the same setup.  The lithium batteries shown in the videos have a similar form factor to the MM SLAs, ie, they fit in the Ryobi battery tray nicely.

 

Here is the YouTube video I found most helpful...

https://www.youtube.com/watch?v=8qRRcIc0mgQ

Edited October 6, 2023 by Brad S
Added YouTube video