Yup, two versions, a zero turn faux commercial one, and a smaller riding style.
Ryobi Zero-Turn Mower SLA to LiFePo4 Conversion - (Updated - Build Complete With Pics!)
- Thread starter AMDPower
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The smaller style was only 2800
UltrasoundJelly
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Hey zamondo, I was looking into this exact question this past fall and I ultimately decided to build a 48v battery as others have done to save money and for the experience, but I was strongly considering going with a drop-in replacement as you're considering. For either drop-in replacement option (12v x 4 or 48v x 1) you won't need to replace the wiring harness or worry about additional cooling. The stock fuel gauge and charger should be replaced though. The stock battery meter / fuel gauge is a simple volt meter that converts the SLA voltage to a percent charge based on a look-up table and will be very inaccurate for LiFePo4 because the voltage-SOC curves are so different. A cheap and accurate fuel gauge can be purchased on Amazon but will require a little modding to install in the current panel. The new meter is a little bigger than the old. As for the stock charger, others here have gotten the stock charger to work with custom batteries. It likely will work with a drop-in replacement also but to maximize battery life you should get a charger that is designed for LiFePo4. The one I purchased is really robust, built like a tank. It cuts off once charging is complete (smart charger) and has a current adjustment knob that I've set to 15amps to not overwhelm the charger port wiring. It's not waterproof is the only negative I can see. I plan to move the charger cord from the old charger to use on the new one, which has screw terminals. Not yet sure if I'm going to have to install ring terminals on the old charger cable.
As for the 12v x 4 drop in option, this will be the easiest to install because the batteries are the same size but from what I've read you need to 1) ensure that they are rated for series installation and 2) you might not get the maximum power out of the bank because as you charge them the weakest battery could prematurely cut off further charging, and as your discharge them the weakest battery would cut out the bank early. There are a bunch of options for drop-in 12v replacements with widely varying prices and warranties. I didn't go too far down this rabbit hole, but there's so much competition here prices have gotten really good.
As for the 48v replacement, the biggest challenges here are 1) finding a replacement that fits in the space and 2) figuring out how to secure the battery to battery tray. I found two possible options for drop-in 48v batteries that'll fit: I've emailed Signature Solar re: this 48v battery that'll fit and they're telling me that it's more of a slow 'n steady style deep cycle battery that wouldn't work well for mowers. Kinda implied that they wouldn't honor a warranty if used this way. The second drop-in 48v I've found that fits is going to be the Dakota Lithium. It's the best option I've found but comes at a price premium of $2700. Nice warranty. Biggest issue purchasing this one is they frequently have delayed shipping (seems like a common theme for all LiFePo4 batteries that aren't 12v drop-ins). Securing this battery in place will be key, maybe some straps combined with a sticky rubber? The front and back battery tray clamps are adjustable so you could use them to minimize front-back movement.
Good luck and please post pictures once you've finished your install.
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Hedges
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If you put mower on a trailer and drive between jobs, I would think you'd want a generator on the truck engine to recharge it.
We understand engine-driven yard equipment produces much more emissions than do modern vehicles, so I'd think this would be a good solution top off between jobs, having recharged from the grid overnight. Unless the lithium batteries are sufficient for a full day.
It would be just my luck that Ryobi would come out with a lithium powered mower right after I by the older model. Its almost almost impossible to get anything lithium shipped to Hawaii, HD ships nothing out here… except the Zero Turn for some reason.
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rio
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Are you sure it's lithium-powered? I can't find any information online other than the AGM-powered ones (at the prices that you mentioned).
These are all the riding mowers listed in the Ryobi website: https://www.ryobitools.com/products/outdoor/mowers/riding-mowers
They're all have lead-acid batteries.
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Lithium ion emblems on the mower.
I will take pics next time I'm there.
I agree there is no information about it online for some reason.
I will take pics next time I'm there.
I agree there is no information about it online for some reason.
Thank you for this info UltrasoundJelly, I like the idea of the single 48v, it sure is pricey. If I did choose to go with 4 separate 12v's for ease of installation, is there another option other than having 4 separate chargers to charge them equally each time? I'm guessing I would have to disconnect all the batteries that are connect in series each time I charge it if I had 4 seperate chargers, which really isn't an option. And if I can get them charged equally, would they discharge equally. It would suck to have one weak battery shutting me down prematurely. Maybe that's where some kind of charge controller comes in? And how bad is it if all the batteries don't charge equally I wonder. If I'm only loosing 20 minutes due to a premature shut down, but gaining an hour or more with the lithium setup, that's probably something I could live with... unless it's harming the batteries. One question about the Dakota 48v, it's rated at 96Au and AMDPower had mentioned his mower peaked at 100Au for a few seconds. Would that be an issue? Overall, I'm looking forward to doing this conversion. I'm thinking I may be able to use the batteries that I remove from the mower to build a little charging station on my trailer for my electric tools so they don't go to waste. Thanks again. The mower arrives around March 17th, so I've got a bit of time to work out the battery setup.
rio
New Member
Hi zamondo,
I'm not an expert, but I don't think you *have* to charge them separately if you go with 4 batteries in series. As long as their BMS have overcharge protection, then series charging should be fine. If they are well-balanced out of the factory, I think they would hold very similar SOC throughout their charge/discharge cycles. If they begin to drift over time I suppose you could charge them individually once to get them back to sync. As USJ said, you definitely want to make sure that whatever battery you pick can support 4 units in series, as they not all do.
For charging, there is a middle ground option: a 4-bank charger, like this one: https://lithiumhub.com/product/ioni...gmMiN-zxlv3mWu2nlL-p745Tr0ixZb_gaAnxBEALw_wcB (this one is 10A per channel, I'm sure you can find something higher)
You would have to double-check, but I think with a 4-bank charger you don't even have to disconnect the batteries from each other. It's still not as convenient as a single plug but not too bad either.
Re Dakota discharge rate, if you look at the specs, it says "100 A max continuous, 200 A max pulse for 3-5 minutes", so no issues there.
If you're feeling adventurous to build your own battery bank from cells, you could go for 200Ah and be able to cut 5+ acres on a single charge! Somebody in here is doing just that. If you fly me to Hawaii I'll give you a hand
.
I'm not an expert, but I don't think you *have* to charge them separately if you go with 4 batteries in series. As long as their BMS have overcharge protection, then series charging should be fine. If they are well-balanced out of the factory, I think they would hold very similar SOC throughout their charge/discharge cycles. If they begin to drift over time I suppose you could charge them individually once to get them back to sync. As USJ said, you definitely want to make sure that whatever battery you pick can support 4 units in series, as they not all do.
For charging, there is a middle ground option: a 4-bank charger, like this one: https://lithiumhub.com/product/ioni...gmMiN-zxlv3mWu2nlL-p745Tr0ixZb_gaAnxBEALw_wcB (this one is 10A per channel, I'm sure you can find something higher)
You would have to double-check, but I think with a 4-bank charger you don't even have to disconnect the batteries from each other. It's still not as convenient as a single plug but not too bad either.
Re Dakota discharge rate, if you look at the specs, it says "100 A max continuous, 200 A max pulse for 3-5 minutes", so no issues there.
If you're feeling adventurous to build your own battery bank from cells, you could go for 200Ah and be able to cut 5+ acres on a single charge! Somebody in here is doing just that. If you fly me to Hawaii I'll give you a hand
.Just assembled a 100Ahr battery pack using batteryhookup's cells. (photo's later)
With DalyBMS.
Using the CON120AC36/48DC Aims charger. DigiKey 229$.
Am wondering about the simple capacity gauges that state you must deplete the battery to set the zero state voltage. Such as this one. https://www.amazon.com/gp/product/B08HWFPGL5/?tag=thingiverse09-20&th=1
Is there a method to fake the empty voltage without pulling the entire pack down?
Next I'm web surfing to find a compatible 3 pin plug/socket to use with my GE Electrak riders. Found it. Delta-Q. Pricey receptacle but fits.
With DalyBMS.
Using the CON120AC36/48DC Aims charger. DigiKey 229$.
Am wondering about the simple capacity gauges that state you must deplete the battery to set the zero state voltage. Such as this one. https://www.amazon.com/gp/product/B08HWFPGL5/?tag=thingiverse09-20&th=1
Is there a method to fake the empty voltage without pulling the entire pack down?
Next I'm web surfing to find a compatible 3 pin plug/socket to use with my GE Electrak riders. Found it. Delta-Q. Pricey receptacle but fits.
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UltrasoundJelly
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If you know your pack's capacity you can just enter that value as 100% without taking the pack all the way down.
knifeman85
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I am 100% new to this and this is my first post here. I have so many questions and maybe I should consult Prof. Google before I go asking them here.
I recently sent my Ryobi Zero Turn in to Home Depot (had to be shipped from WA to AZ) because I believed the blade motor controllers were malfunctioning. I could mow anywhere from 3 minutes to 15 minutes then the blades would cut off/stop moving and I still had full speed capability and no slow down in movement. So I got a call yesterday saying that the Batteries, which have about 20 hours of use, are bad and need to be replaced at a cost of $1100.00 or more. I requested that they look into the motor controllers, as I don't want to send it back for that issue.
the news of the bad batteries got me started looking into changing out my own batteries, then incidentally, over here to change to a different kind of battery.
I've read through this forum, and with all the talk of voltages, BMS's. battery charge balancing, special chargers, etc. . . I'm wondering if I am in over my head as I have not done this before. I have 3d printers, and done home electrical and I'm a decent DIYer, but if I undertook a thing like this, would I need to buy special equipment to test and charge batteries just for the install?
Some posts make it seem like I could purchase four 12v 100ah batteries, a LiFePo4 charger, and a new gauge, and I'd be set. But some posts make it seem like that is a terrible idea and it wouldn't work and I need to buy batteries from china, build boxes, buy various electronics and dedicate my life to charging and maintaining said batteries.
Basically, I think this is the way I need to go, because I can't justify spending 1000 bucks on lead every 2 years, but is there a simple run down of parts that would be needed to do the simplest upgrade to LiFePo4 on this Mower, without getting a degree in electrical engineering?
Thank you to anyone that reads through this and answers. I also have a 21.6kW solar array that was installed last year, I look forward to reading through posts about DIY solar and am potentially interested in coming up with battery backup for my solar as well.
I recently sent my Ryobi Zero Turn in to Home Depot (had to be shipped from WA to AZ) because I believed the blade motor controllers were malfunctioning. I could mow anywhere from 3 minutes to 15 minutes then the blades would cut off/stop moving and I still had full speed capability and no slow down in movement. So I got a call yesterday saying that the Batteries, which have about 20 hours of use, are bad and need to be replaced at a cost of $1100.00 or more. I requested that they look into the motor controllers, as I don't want to send it back for that issue.
the news of the bad batteries got me started looking into changing out my own batteries, then incidentally, over here to change to a different kind of battery.
I've read through this forum, and with all the talk of voltages, BMS's. battery charge balancing, special chargers, etc. . . I'm wondering if I am in over my head as I have not done this before. I have 3d printers, and done home electrical and I'm a decent DIYer, but if I undertook a thing like this, would I need to buy special equipment to test and charge batteries just for the install?
Some posts make it seem like I could purchase four 12v 100ah batteries, a LiFePo4 charger, and a new gauge, and I'd be set. But some posts make it seem like that is a terrible idea and it wouldn't work and I need to buy batteries from china, build boxes, buy various electronics and dedicate my life to charging and maintaining said batteries.
Basically, I think this is the way I need to go, because I can't justify spending 1000 bucks on lead every 2 years, but is there a simple run down of parts that would be needed to do the simplest upgrade to LiFePo4 on this Mower, without getting a degree in electrical engineering?
Thank you to anyone that reads through this and answers. I also have a 21.6kW solar array that was installed last year, I look forward to reading through posts about DIY solar and am potentially interested in coming up with battery backup for my solar as well.
Hedges
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Earn the EE degree in your garage, cut your teeth on the LiFePO4 battery bank for mower, and you'll be ready to build the battery backup system.
A small battery backup system for phone/internet could be an off the shelf "Solar Generator", but if you want anything on the scale of whole house backup, on the order of 10kW to 20kW peak loads and several 10's of kWh of storage, DIY with individual cells is likely the lowest cost approach. 1000 bucks ain't nothing compared to a bank that size.
Although, there are alternatives. I use AGM for whole-house backup, and minimize what I power at night. During the day, my GT PV inverters can power everything in the house, and adjust their AC output up or down to match loads plus battery recharging requirements. Does your PV system do "frequency-watts" feature of UL-1741-SA? That is key to integrating with a battery inverter.
I’m about to try out the “simple way” I have no time to build my own battery. My mower is brand new, it’s actually still at HD, I’m going to pick it up tomorrow. I’m going to order 4 of these battery's, the total with tax is about $1600. https://amperetime.com/products/ampere-time-12v-100ah-lithium-lifepo4-battery
They do free shipping and have a 3% off coupon. The battery has a built in BMS and they say they can run 4 in serial. Also the dimensions are the same as the OEM so it should be a drop in solution unless i’m missing something. The FAQs say it has a max 5120w load power. That would be the only thing i’m not sure of, what the mowers max load is, but I’m guessing it will be enough. I’m going to get a new charger and voltage meter as mentioned I should previously. Hopefully that is all I will need. I’m not sure how to wire up the charger snd meter yet, but I’m guessing it’ll be pretty straightforward. I’ll document the process and post here. I have to get the batteries shipped to a California address then shipped by boat to Hawaii so it may take about 3-4 weeks before I can do the swap.
knifeman85
New Member
I'm eager to see this build as it sounds closer to what I'm more comfortable with and potentially easier to revert back to the old system if I need to send it in for an unrelated warranty issue as I have another year on the warranty... Are you at all worried about warranty issues with the conversion? I didn't really think about it when I purchased the mower, but I am more concerned about it now in the last year. Hopefully HD finds out if there is a motor controller issue and fixes that, and I can worry about battery replacement on my own time.
knifeman85
New Member
That question there at the end I do not know how to answer, like where would I find that info? My system was not a DIY install, I'm running 54 Solaria 400w panels with 54 IQ7a Enphase micro inverters. I am on a Net Metering system/Model here in WA so battery backup would be mainly for power outages or offsetting my peak usage during the winter months. I'm currently in school for a Mechanical Engineering Degree as that more aligns with my interests, electrical engineering is definitely important and I'm sure I'll learn a little about it as schooling progresses, but it doesn't interest me as much.
I'm very interested in not burning down my shed, or my house, while attempting to get a mower on a different battery system though.
Warranty’s are kinda useless for me where I live, which is one of the outer islands in Hawaii. If anything breaks they I have to send it to the mainland. Usually with the time and money involved its easier to buy a new piece of equipment. I mow yards for a living so I pretty much rely on Amazon and me fixing any problems. Maybe if I had two of everything I could afford to take it back to the manufacturer. As it is, I have to get everything from Home Depot and make sure its something that they keep in stock. Going out on a limb with this mower, but things breaking down and warranty issues is why i’m going all electric… hopefully less issues, although its been a painful experience getting all the extra batteries I need.
Hedges
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I think IQ7 and IQ7a do have the feature of reducing wattage output in response to frequency increase. Possibly configuration or firmware update is required. Search the forum for people doing AC coupling with them. GXMnow, for instance:
Adding storage to my Enphase system
I am still fairly new on the forum, tried to answer a few questions as I asked some, and have been talking about my plans and purchases. I figure this is the right place to talk about what I am doing and where it is going. My existing system is a very typical Enphase setup. I have 2 arrays of 8...
diysolarforum.com
Enphase does offer a battery product, a bunch of microinverters each with a lithium battery.
Several AC coupled battery inverters should work. Schneider, Outback Skybox, Sunny Island, Sunny Boy Storage, SolArk.
Some include a relay transfer switch, so downstream loads are protected like a UPS. Some require external switch.
Some work with lead-acid batteries, and some people use lithium without communication with BMS. Others have communication.
Some are only proprietary high-voltage lithium battery (or a battery with boost converter.)
Capabilities vary, such as surge current to start motors, and programming to shave peak loads or move consumption/production time around.
The biggest question is, "How much would you like to spend?"
GT PV with net metering can be significant savings over utility rates. Any battery system probably costs a premium.
The one I use, Sunny Island, has 56A transfer switch (if paralleled can pass 112A). That is a limit on how much GT PV can be downstream.
your system is so large you would probably keep some straight on grid and move only some onto the battery inverter.
There is a lot of talk lately about "server rack batteries", which are packaged 19" rack mount, and can be paralleled.
You probably want UL listed, or at least keep batteries away from the house. (My AGM are UL Recognized, which is sufficient for that chemistry.)
UltrasoundJelly
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Well I am just about done with my battery build ( 100 Ah 16s CALB cells with Overkill BMS), save for a couple of dust shields... and I run into a problem. First, the battery worked well when driving my mower up and down the yard. No issues with the actual battery function, but I haven't yet mowed. First mow tomorrow. Pictures to follow later.
However, when I went to plug in my AIMS charger using the built-in quick Delta-Q connect there was a big arc with sparks and I think I fried the receptacle and plug. I'm getting resistance values in the mega-Ohm range across both the receptacle and the plug on the positive wire. Not really sure what happened, the charger was plugged in but the charger switch was off.
So I'm stuck considering 1) ordering a new receptacle and plug or 2) getting a whole new quick disconnect to charge. Any thoughts / opinions welcome. @AMDPower I know you had arcing with yours, did you solve this issue?
However, when I went to plug in my AIMS charger using the built-in quick Delta-Q connect there was a big arc with sparks and I think I fried the receptacle and plug. I'm getting resistance values in the mega-Ohm range across both the receptacle and the plug on the positive wire. Not really sure what happened, the charger was plugged in but the charger switch was off.
So I'm stuck considering 1) ordering a new receptacle and plug or 2) getting a whole new quick disconnect to charge. Any thoughts / opinions welcome. @AMDPower I know you had arcing with yours, did you solve this issue?
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