Ryobi Zero-Turn Mower SLA to LiFePo4 Conversion - (Updated - Build Complete With Pics!)
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bobbie_ohio
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Anybody have ideas on where to troubleshoot issues once we upgrade? I had it working, ran it about 20 minutes. Hooked it up to the charger and found out one of my cells keeps going over limit faster than others. So I left it unplugged and was going to go back to it and drive it down to zero so I could calibrate my meter. So now days later I plugged in my key and I get nothing. The charger can still charge the battery when I hook it up and the 125amp fuse ohms ok. There’s nothing to the panel. It doesn’t beep that the key is in and no rider and reverse doesn’t beep. What ryobi part would keep all this from happening ?
Hedges
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You need your cells top-balanced to some moderately high voltage, like 3.65V/cell (one time, before using system)
Then you need to charge the series connected pack to a lower voltage, like 3.5V/cell
The idea is, so far as SoC doesn't diverge too much, CV/CC charger settles to some voltage and passive balancer bleeds off the high ones.
Then you need to charge the series connected pack to a lower voltage, like 3.5V/cell
The idea is, so far as SoC doesn't diverge too much, CV/CC charger settles to some voltage and passive balancer bleeds off the high ones.
bobbie_ohio
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I did top balance them to around 3.60 but maybe I’ll try again. The voltage is at 54+ though why would the mower not give me anything on the ignition side?
Hedges
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Balanced to 3.60V and charged to 3.375V/cell seems good enough. Unless that is too low to trigger passive balancing.
I'm not familiar with the mower, or how it's "ignition" circuit works.
Another source for cell voltage problems can be poor contact between bussbars and cells. Voltage would go higher during charging, lower during discharging. While charging, check voltage of each with DMM. If possible, use probe to measure voltage from each cell terminal to the busbar.
Removing aluminum oxide, using corrosion inhibitor, proper torque can help with contact. Make sure cables don't cause screws to rotate.
Sometimes, poor connection of lead to BMS is at fault, like in the BMS connector.
I'm not familiar with the mower, or how it's "ignition" circuit works.
Another source for cell voltage problems can be poor contact between bussbars and cells. Voltage would go higher during charging, lower during discharging. While charging, check voltage of each with DMM. If possible, use probe to measure voltage from each cell terminal to the busbar.
Removing aluminum oxide, using corrosion inhibitor, proper torque can help with contact. Make sure cables don't cause screws to rotate.
Sometimes, poor connection of lead to BMS is at fault, like in the BMS connector.
rio
New Member
This may be related to the lockout circuit, similar to what happened to @UltrasoundJelly (see the bottom of post #338). When you turn the key, do you hear the lockout relay "thud"? If not, you might want to try bypassing the lockout circuit like he did.
I can't imagine this being related to the cell voltage over limit. I assume the BMS is just handling this as it should. And as you said, if you're measuring 54 volts in the pack then this is not a voltage issue (unless this voltage plummets when you're turning the key, which would indicate issues with the pack, but I would think this is unlikely).
I can't imagine this being related to the cell voltage over limit. I assume the BMS is just handling this as it should. And as you said, if you're measuring 54 volts in the pack then this is not a voltage issue (unless this voltage plummets when you're turning the key, which would indicate issues with the pack, but I would think this is unlikely).
bobbie_ohio
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Is that blue wire connected to some 12v line or to the positive of the 48v battery?
bobbie_ohio
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rio
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Yeah. It has two connectors: one with 3 wires (yellow, black, red) going towards the instrument panel, and another one with a single blue wire going towards the charge port. What USJ did was disconnect the blue wire and connect it directly to battery positive (48v). This will permanently disable the lockout condition.
bobbie_ohio
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Dang it. It’s because I was gonna use the blue connect to hook into my charger and so snipped that. As soon as I put the red wire back in there I get clunk. I need to find a local source for an Anderson type connector so I can put this red wire back in that loop and get my charger easily connected. Thanks for your guidance
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UltrasoundJelly
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Glad you figured it out. Here's where I sourced my Anderson connectors:
https://powerwerx.com/anderson-power-powerpole-sb-connectors
Hi all,
A lot of great info in here. I'd love to get my Ryobi converted. I'm trying to have someone build my battery with BMS. They have a few questions I hope someone here can help with:
The connector to the Mower is it an Anderson style?
What is the discharge current? 1C?
Thanks for any help
A lot of great info in here. I'd love to get my Ryobi converted. I'm trying to have someone build my battery with BMS. They have a few questions I hope someone here can help with:
The connector to the Mower is it an Anderson style?
What is the discharge current? 1C?
Thanks for any help
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icenov
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Yes, Anderson.
From the manual, the cutting power motors are 2600 W and drive motors 1500 W, so total of 4100 W. Assume a battery voltage of, say 45 V under full load, this means 91 A, but probably higher due to losses -say 100 A. As the batteries are supposed to be 100 Ah (LPC12-100 (12V 100 Ah)) then discharge current would be 1 C. As a check, I think the inline fuse is 125 A, so can't be far wrong.
The dimensions aren't the same. I've been looking for a similar "drop in" solution. I have the 75AH version of the RYOBI ZTM. What I've found is the following:
OEM (Leoch LPC12-75): 10.2 x 6.61 x 8.43 inches
Ampere Time 12V 50Ah: 7.79 x 6.53 x 6.69 inches
Ampere Time 12V 100Ah: 13 x 6.82 x 8.48 inches
I was about to purchase 4 of the 100Ah versions and I started to look into how I could get them to fit... I'm not sure you can? I'd need almost 6 more inches in depth. I'd likely have to build something to replace the sled (that's assuming I had 6 inches of space available inside). Not sure I want to go that route when I can get the 50Ah and secure them on the provided sled with the RYOBI.
I've replaced the Leoch batteries 2x (once per year from RYOBI thankfully) and I'm done with this lawn mower if I can't find a better use. The batteries make me not like the mower. If I can solve the battery issue then I'll be thrilled
For those that have a ryobi electric mower, would you buy it again? My snapper finally gave out and I am looking into an electric mower. I actually went to get a cub cadet today and it would not even turn on (error codes) to get it loaded. So I returned it. This has me a little worried about electric, but I love the idea of it. Just curious about opinions since it seems like many of you have owned ryobi mowers for some time.
My thinking is to get the 30in 50ah. I only have like 1/2 acre. Run it until the batteries die and then get some LiFePo4 to go in it. I currently have 560ah 12v in my van with an electrodacus sbms.
has anyone had any other issues with motors or controllers?
I have had 3 gas power riding mowers over the years and just got tired of maintaining them constantly. My wife is the one that does the mowing and she can be hard on them. But all the cleaning of carburetors, filters and fuel system in general, adjusting valves, adjusting/replacing belts, changing oil, even buying transporting gas got old...or I got old and I'm tired of doing it. She has really liked our Ryobi. The only complaint she has is waiting for the batteries to recharge before she can finish her mow. We successfully got 3 seasons out of the SLA batteries but someone unplugged the mower this winter and the batteries are now dead. One of them actually shows a negative charge...not sure how common that is.
I still sharpen the blades about 1 a month but not much maintenance beyond that.
Anyway, we have not had any issues with the motors or controllers. So we have liked the mower to this point and I would buy it again. And I just ordered a new LiFePo4 power source that will hopefully last for the life of the mower and allow us to finish a mow on a single charge. Just FYI, we have 5 acres...I mow most of it with a diesel tractor and "brush hog" and we use the Ryobi on about 1.5 acres.
The Ampere Time 12v 100Ah LifePO4 batteries should fit in the mower fine, although I have not tried. If you look at the dimensions of the OEM 100Ah batteries for these mowers (Leoch LPC12-100) the dimensions are 13 x 6.81 x 8.66. Nearly identical to AT and many of the Amazon 12v 100Ah LifePO4 ones. The battery frame should have bars on the sides that can be adjusted to the length of the battery as seen in the photo. This was from a post in the first page of this thread.The dimensions aren't the same. I've been looking for a similar "drop in" solution. I have the 75AH version of the RYOBI ZTM. What I've found is the following:
OEM (Leoch LPC12-75): 10.2 x 6.61 x 8.43 inches
Ampere Time 12V 50Ah: 7.79 x 6.53 x 6.69 inches
Ampere Time 12V 100Ah: 13 x 6.82 x 8.48 inches
I was about to purchase 4 of the 100Ah versions and I started to look into how I could get them to fit... I'm not sure you can? I'd need almost 6 more inches in depth. I'd likely have to build something to replace the sled (that's assuming I had 6 inches of space available inside). Not sure I want to go that route when I can get the 50Ah and secure them on the provided sled with the RYOBI.
I've replaced the Leoch batteries 2x (once per year from RYOBI thankfully) and I'm done with this lawn mower if I can't find a better use. The batteries make me not like the mower. If I can solve the battery issue then I'll be thrilled
I'm not sure if it is on this thread or another one but I've seen where anything less than ~60Ah will not even start this mower much less be enough for it. These mowers pull a good amount of amps with the blades on and going up an incline. I believe this has been discussed on previous pages as well.
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I have the 75Ah non-zero turn version and I am going on my 5th season still on the original SLA batteries. I would absolutely buy it again. I only have about 1/3 of an acre to mow so I hardly use any battery. I also use a PowerPulse Battery Maintainer and have a solar charge controller to keep the batteries topped off. I like to think all of this will help my batteries last as long as possible.
Like @RipRiley said, you have to keep this mower charged, especially over the winter when not in use, otherwise you will be buying new batteries often. Also, if you have a larger yard and consistently go under 50% charge, the batteries will likely not last very long.
You guys sparked my interest with these Ryobi ZT mowers, but after using 60" commercial Scag and Xmark equipment, these things are like toys in comparison and not really suited for my needs. I'm sure real commercial electric ZT's are out there, or coming soon, but I can only image what those would cost!
I have a couple of extra commercial 60" Xmark zero turn mowers with bad or questionable engines, but the machines are solid otherwise. I don't have the time to reinvent the wheel to try converting them over to all electric, but if someone sold a conversion kit for the blades, wheels, etc and came with the electronics to control it all, I'd be tempted to do it and add a large DIY battery! I suspect there would (or will) be a market for this as everything is going electric these days, and these commercial mowers are not cheap to replace!
I have a couple of extra commercial 60" Xmark zero turn mowers with bad or questionable engines, but the machines are solid otherwise. I don't have the time to reinvent the wheel to try converting them over to all electric, but if someone sold a conversion kit for the blades, wheels, etc and came with the electronics to control it all, I'd be tempted to do it and add a large DIY battery! I suspect there would (or will) be a market for this as everything is going electric these days, and these commercial mowers are not cheap to replace!
I have the Ryobi 100ah zero turn and have been happy with it, actually surprised by how well it has performed for almost 3 years now. Range has decreased by about 1/3 and I'm considering LifePo4 replacements. I have 4 1/2 acres to mow and use the Ryobi along with other gas mowers to get it cut. I run the Ryobi till it tells me "you better get home" just about all the time, which isn't good for AGM batteries.
Would I buy it again? Not if I had the option to get a Lithium Ion powered unit for a comparable price. At the time I purchased mine there were no other electric options in this price range. Ryobi is supposedly releasing a new line of Lithium Ion powered mowers, don't know what they'll be asking for them.
Not exactly thrilled about having to put another $1,000 - $2,000 into it to get my range back. If I go the LifePO4 route I would, supposedly, be set for the rest of the mowers life (maybe mine too!). Now the question is: to build a battery, go with 4 - 12v's or spend big money for a 48v, ready to go unit?
UltrasoundJelly
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Good question. I bought the 75 Ah version in May '20 for $3550 (got a slight discount because it was delayed shipping). I have 8/10 acre of grass to mow on a 15-18° grade (see pics). When I first got the mower I was fairly pleased with it. Full yard mow took about an hour and used 40-50% of the SLA battery capacity at 80°F. Mow quality was good, easy to maneuver. Biggest initial downside was all the skidding on the slope with the turf tires. Once I replaced them with some super lug tractor-style tires it ran like a beast. Much happier with the mower after that, but it did still feel sluggish going up the steep slope, running at about 1/3 speed despite having the control bars floored forward.
By the end of the very first season I was seeing the remaining SLA capacity dip into the 40s and sometimes 30% range, so I decided to start splitting up the mowing over 2 days. I did this the entire second season to try to preserve the batteries, but despite my efforts the capacity really took a nosedive. By the end of season 2 I had to recharge twice for a single mow, so mowing over three days. With a total cost of $800 for SLA replacements it only made sense to pursue a lithium replacement. I think my total battery build + lithium charger was on the order of $1300 + my time. So getting close to $5k. I love the mower now. I use 30% of the capacity, and it zips up the hills with much more pep. It also feels great knowing the mods I did worked... but I do like to tinker.
If I were in the market now I would probably not get this mower, or any mower that uses SLA. I'd look for a mower in the $5k range with 70+ Ah lithium capacity. Ryobi vs Ego. Looks like the Ego is $5500 for 40 Ah, so not sure if that would cut it with me. Would be really tempted by the Ryobi Lithium version of this mower, but pricing not yet out. I'd never again consider a gasser.
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Thanks for this. I have a relatively small yard less than half an acre. so I was planning to get the 50ah. We need to mower more so my wife can pull the lawn trailer around the yard. I thought I could get the 50ah ($2500) and use the sla as long as possible then slowly put money aside for the lithium upgrade. I have built numerous lifepo4 packs, so I don't really see it being an issue. By what I have been able to find, It seems as though ryobi mowers are much more reliable than some of the other brands. Cub Cadet for one has some serious issues. I have almost purchased two that had issues at the store.
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