gwang_hoops
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- May 23, 2022
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58.4V is recommended for 16S LiFePO4. I was thinking LiFePO4 15S or Li-Ion 13S would be fine. This situation would only matter if you had a faulty battery or wanting a slightly lower SOC.
Ryobi Zero-Turn Mower SLA to LiFePo4 Conversion - (Updated - Build Complete With Pics!)
- Thread starter AMDPower
- Start date
Strangest thing just happened. After mowing for an hour, the monitor showed over 60% charge remaining. I parked the mower for about an hour, then decided to put it away. As soon as I turned the key on I heard a click and then had no power. I checked the battery and had a voltage of about 2v. Tried the charger and that didn't work either. I remembered I had an old DC variable power supply. Set that to about 50v and reset the battery with that. Everything came back to life. I was worried that somehow I ran it down too low and the BMS turned off for low voltage but checked with my meter and it had 53.25v. Worried now about what may have caused the BMS to shut down as soon as the key was turned on. All connections are tight, Temps in the 70's, no load on the battery other than turning the key on.
icenov
New Member
I've had the same thing - battery well charged but no power. In my case it's due to the BMS turning off after some idle period. Connecting the charger brings it back to life, as you found. I've got a Daly BMS with bluetooth that I can connect via phone app and change the idle period to never (i.e. don't turn off). I think many of the BMS's turn off to avoid running down the battery, but with these large capacities, that's not likely to happen. What BMS have you got?
I actually heard the BMS click off when I turned the mower key on. Attaching my charger didn't wake it up, I had to use a separate power supply. My battery came as one unit with the BMS preinstalled. Don't have any real info on it. I could try to contact the battery manufacturer for info.
I have been following this thread for a while. I am surprised how many people claim their original batteries failed after just one season. Did you regularly drain the batteries below 50%?
As a reference, I have about 60 hrs on my 100AH Ryobi. There there is some capacity loss but not much. This is my third season.
This tractor is advertised as capable of up to 2.5 hrs run time. Clearly, people who use it as advertised will end up with useless junk after just one year. Isn't this a good case for a class action based on false advertising?
My lawn is about 1 acre. Knowing that AGM batteries suffer if drained below 50%, I never used this tractor for more than an hr before I would recharge it. However, if the manufacturer claims 2.5 hrs is fine and does not warn against it, I think the tractor should be perfectly capable of doing this regularly without any harm.
I think Ryobi screwed up customers, intentionally, and they continue to do so. The tractor should simply prevent the user from draining batteries below 50% if doing so is critical to durability.
As a reference, I have about 60 hrs on my 100AH Ryobi. There there is some capacity loss but not much. This is my third season.
This tractor is advertised as capable of up to 2.5 hrs run time. Clearly, people who use it as advertised will end up with useless junk after just one year. Isn't this a good case for a class action based on false advertising?
My lawn is about 1 acre. Knowing that AGM batteries suffer if drained below 50%, I never used this tractor for more than an hr before I would recharge it. However, if the manufacturer claims 2.5 hrs is fine and does not warn against it, I think the tractor should be perfectly capable of doing this regularly without any harm.
I think Ryobi screwed up customers, intentionally, and they continue to do so. The tractor should simply prevent the user from draining batteries below 50% if doing so is critical to durability.
Had my 100ah zero turn since 10/2019. Don't know the hrs on it cause the battery gauge had to be replaced thru Ryobi once and I just replaced that gauge with a good battery monitor and never bothered to check hrs. I can say it has seen plenty of use on our 4 1/2 acre property.
I never got 2.5 hrs mowing out of a charge.
Almost always ran the batteries down to where the blades shut off, about 15% on the gauge. After 2 1/2 years, the original batteries still had useful life in them and I could get about 40 mins or about 1/2 - 3/4 acre out of a charge. I used the hell out of those batteries and the mower, but also took good care of them. In my case, neither the batteries nor the mower became useless junk after a year.
All the old batteries test good on my cheap battery tester and I already started using them for my boat.
Ryobi definitely knew that battery durability would be an issue, hence the 1 year battery warranty vs the 3 yr mower warranty. I think a lawsuit would be an uphill battle. Who knows what type of perfect conditions they tested these mowers on but I'll bet they were the best possible. There's a lot of variables to consider with things like this.
Little different situation
Bought a used 1985 lifted EZ go 36 volt golf cart ? with Trojan flooded cell batteries ?. Got another 3 years out of them. Started dying and range went way down.
Studied all my options then ordered 3 12 volt lithium batteries.
Saw Big Battery had an all in one battery called the gator max with charger and I cancelled my other order.
Bought the gator max, removed old batteries which I got a payout on from a recycler, slipped in the new battery, hooked it up and it’s worked flawless ever since. Rarely have to charge it. I saved almost 300 pounds to boot ?.
I believe they also have a 48 volt battery.
Bought a used 1985 lifted EZ go 36 volt golf cart ? with Trojan flooded cell batteries ?. Got another 3 years out of them. Started dying and range went way down.
Studied all my options then ordered 3 12 volt lithium batteries.
Saw Big Battery had an all in one battery called the gator max with charger and I cancelled my other order.
Bought the gator max, removed old batteries which I got a payout on from a recycler, slipped in the new battery, hooked it up and it’s worked flawless ever since. Rarely have to charge it. I saved almost 300 pounds to boot ?.
I believe they also have a 48 volt battery.
gwang_hoops
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rio
New Member
I tried with mine to keep it over 50%, but wasn't always disciplined enough and a few times got far below. But, the percentage displayed in the stock gauge is based on voltage, not on true SoC, so it's kinda meaningless to begin with.
2 years in, I was only getting about 20 minutes per charge. When I tested the batteries 3 were fine and one was bad. This seems to be the common predicament. I don't know if this is a common failure mode with series AGM batteries, or whether there's some bad quality control with the Leoch ones.
I agree that it's very disingenuous of Ryobi to advertise "up to 2.5 acres". I wonder if they just based that on the theoretical amount based on what 100 Ah can get out of this mower's power consumption, and not on any actual testing.
2 years in, I was only getting about 20 minutes per charge. When I tested the batteries 3 were fine and one was bad. This seems to be the common predicament. I don't know if this is a common failure mode with series AGM batteries, or whether there's some bad quality control with the Leoch ones.
I agree that it's very disingenuous of Ryobi to advertise "up to 2.5 acres". I wonder if they just based that on the theoretical amount based on what 100 Ah can get out of this mower's power consumption, and not on any actual testing.
eleven_brews
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- Jun 2, 2022
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You can just drop the 100Ah 12v lifepo4 batteries in and use the existing charger. The reason it’s suggested to use a timer is because the original charger will try to over charge the batteries due to the fact that the charge profile is meant for AGM lead acid batteries. The BMS in the lifepo4 cells should prevent that, but it’s not good practice to rely on that safety mechanism to stop charging. Also, it may still be allowing the cell voltage up to a 3.65v which isn’t great for longevity. This is why many have replaced the stock battery meter with a meter that uses a shunt to track how much amp hours have been consumed and set a timer to charge to 80%. The stock DeltaQ charger charges at about 14a so it’s easy to do the math to figure out how long to set the timer for.
Definitely don’t leave it on the charger all the time.
For my setup with a 105ah 16S battery with a Bluetooth-enabled BMS, I’ve just been charging every 3-4 mows and watch the charge level and voltage and just unplug the charger when I know it’s somewhere between 80-90%. If I forget, I have my BMS set with a 3.50v cell high voltage cutoff, which is basically fully charged for my cells.
I would go with drop in cells that come with it’s own charger.
My 36 volt all in one unit came with it’s own charger. I took the old one to a recycle place. Why cheap out when you are spending hundreds if not thousands of dollars ? on a battery replacement? ?
My 36 volt all in one unit came with it’s own charger. I took the old one to a recycle place. Why cheap out when you are spending hundreds if not thousands of dollars ? on a battery replacement? ?
@ryobilifepo4user did you ever figure out your issue? I’m seeing the same thing. Charged 4 12v 100ah ampere time batteries, connected everything the way it was (didn’t replace gauge or change anything else yet), turned the key, one clunk then nothing. Now turning the key doesn’t do anything. Batteries in series reading 54.0V. maybe I’ll try charging in parallel for a bit to better balance? How balanced must they be? Really hope there’s a solution here, I was very excited to get my mower back.
Anyone have any other ideas?
Thanks so much in advance!
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Btw my individual battery readings are 13.50v, 13.56v, 13.53v, 13.39v. Maybe that last one is too out of balance?
Did you try to "wake" the batteries or BMS back up by using a power supply to apply 48v to them? Worked for me twice. Lots of info out there on how to do this.
Thanks @Jakeman not yet but I’ll give that a shot if it happens after letting the batteries balance in parallel first. The instructions that came with the batteries actually mention it is recommended to connect in parallel for 12-24 hours prior to using them in series. I just gotta go out and get some cables to connect then that way cause the little ones that came with the mower won’t be enough for parallel.
Any idea what bms protection is tripping to cause it in the first place? The downside of these off the shelf 12v is not having access to the bms data.
Any idea what bms protection is tripping to cause it in the first place? The downside of these off the shelf 12v is not having access to the bms data.
Just re-read your post. If you have 54v, I don't think they need to be "woken up". Mine showed almost no voltage at all when it happened. Sorry, no other idea, hopefully following the instructions will do the trick. I'm new at this, trying to learn as I go and share what I've learned.
I had to make cables to hook 2 of the old AGM batteries from the mower in parallel to use in my boat. Luckily I had some old welding cable and ordered some ends from Amazon.
My battery is an "off the shelf" 48v with no access to the BMS data as well. Mine shut down twice and I think I know what caused it. Both times I had been mowing, stopped the mower and let it sit outside. Think it got too much sun and caused some heat to build up around the battery, causing the BMS to trip. It is surrounded by black plastic without a lot of air circulation. I now park it in the shade or in the garage and haven't had the problem since.
One of the reasons I went with the 48v is, hopefully, not having to worry about balancing or any other issues with multiple batteries. I do realize my "single" battery is a collection of 16, 3.2v cells. It was almost plug and play except for having to secure the battery differently. Just charge it and go.
So good news for my conversion, I’m up and running. Balanced the batteries in parallel for a day, then re installed in series. My first time hooking everything up I again got the one clunk and dead mower but I just unplugged and replugged the main Anderson connector and for some reason all was good after that. Now finally for a first mow tomorrow and will try to figure out if I’ll be good using the delta q charger or switch to a 48v lifepo4 one I got (though I’d want to splice in the delta q charger plug). I also haven’t yet installed the new gauge but plan to in the near future. Wanted to make sure I was running before figuring out those next steps. Thanks again to all contributors in the thread for helping us newbies figure this out! (And thanks to an amazing neighbor who cut my lawn for a few weeks while I was down!)
rio
New Member
Those are the real heroes!
Been spending WAAAAY too much time researching all this. Thanks everyone for all the info. =)
So my AmpereTime batteries just arrived (4x 12v 100ah), but I've been frustrated finding a decent 48v charger. It seems like most of the 48v chargers have weird issues, like arcing or fuses not actually being connected to anything!
My plan:
1. Use the standard Ryobi charger
2. Get a Junctek battery monitor/shunt https://a.co/d/83fmAe8
3. Use it's option to control a relay to be able to disconnect the third pin on the charger port, which should stop charging. If the third pin disconnecting doesn't stop it, I could also put a bigger relay into the actual charger circuit.
4. Set it to trigger the relay when voltage goes over a certain level (for protection, and because I'd prefer not to go to 100% SOC)
5. Bonus: also can work as low temp charger cutoff since AmpereTime batteries don't have that built in
Does that make sense? In addition to being able to continue using the charger, I'd get a bluetooth battery monitor with a decent little display and data logging. The Junctek only costs about $30 more than the other monitor/shunt options.
So my AmpereTime batteries just arrived (4x 12v 100ah), but I've been frustrated finding a decent 48v charger. It seems like most of the 48v chargers have weird issues, like arcing or fuses not actually being connected to anything!
My plan:
1. Use the standard Ryobi charger
2. Get a Junctek battery monitor/shunt https://a.co/d/83fmAe8
3. Use it's option to control a relay to be able to disconnect the third pin on the charger port, which should stop charging. If the third pin disconnecting doesn't stop it, I could also put a bigger relay into the actual charger circuit.
4. Set it to trigger the relay when voltage goes over a certain level (for protection, and because I'd prefer not to go to 100% SOC)
5. Bonus: also can work as low temp charger cutoff since AmpereTime batteries don't have that built in
Does that make sense? In addition to being able to continue using the charger, I'd get a bluetooth battery monitor with a decent little display and data logging. The Junctek only costs about $30 more than the other monitor/shunt options.
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