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Ryobi Zero-Turn Mower SLA to LiFePo4 Conversion - (Updated - Build Complete With Pics!)

Jakeman said:
Can take some pics if anyone's interested in anything specific. Figured there's plenty of pics of most of the steps I took, exception being how I secured the battery.

I was confused about the monitor as well, but it seemed pretty accurate? The manual confused me by stating that the battery should be fully discharged, enter a larger value, then re-charge and re-enter the capacity. I didn't want to fully discharge the battery, so I didn't follow that step. I did initially enter the 100ah capacity of the battery. I will set it to 100% and see how it goes.

The 8 hrs. of charge is an estimate, should've been close to that. If the BMS tripped, it didn't have the result that AMDPower had, which faulted his Ryobi charger. I charged it again today and it acted exactly like the first charge. Almost forgot about it charging but luckily caught it right before 90% and, like the first charge, the monitor showed some very low, fluctuating amp readings and I disconnected it. I may get tired of monitoring the Ryobi charger and get the proper charger.
Click to expand...

Jakeman said:
Can take some pics if anyone's interested in anything specific. Figured there's plenty of pics of most of the steps I took, exception being how I secured the battery.

I was confused about the monitor as well, but it seemed pretty accurate? The manual confused me by stating that the battery should be fully discharged, enter a larger value, then re-charge and re-enter the capacity. I didn't want to fully discharge the battery, so I didn't follow that step. I did initially enter the 100ah capacity of the battery. I will set it to 100% and see how it goes.

The 8 hrs. of charge is an estimate, should've been close to that. If the BMS tripped, it didn't have the result that AMDPower had, which faulted his Ryobi charger. I charged it again today and it acted exactly like the first charge. Almost forgot about it charging but luckily caught it right before 90% and, like the first charge, the monitor showed some very low, fluctuating amp readings and I disconnected it. I may get tired of monitoring the Ryobi charger and get the proper charger.
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@Jakeman, would like to see some pics of how the battery fit in the compartment. Thanks
 
Lazyboy said:
Hey @RipRiley, how is this setup working for you? Are you happy with it? How are you charging the battery? Can you post more details? What did you have to do to get this installed and up and running? Do you use a different battery gauge or the stock one?
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Basically, I took measurements and asked a few questions on this thread and ordered it custom from the guy on the invoice.
It is working well. I am happy with it. Definitely much more power and longer charge. I'm charging it with a 5a charger I bought from the guy that built the battery $12.50. They actually sent the wrong charger...they sent a 220v and I ordered a 110v but I happen to have a 220v outlet for my air compressor so no big deal for me.
To install: all I did was take out the old batteries, pull off the dividers from the original tray (which are "glued" on), put the new battery in the tray (I had to adjust the ends to allow more room, but it is built to be adjusted), slide in the tray and connect the single anderson connector from the mower to one of the ones on the battery...doesn't matter which one. I then cut a hole in the upper housing to pull the other connector through for charging. If one of the leads was long enough I would have mounted it to the original charging port.
The original gauge lights up but is inaccurate. There is a gauge on the battery but I have lift the seat and pull the cover to view it. I'm sure there are options for bluetooth or other options. I'm actually going to look into that next.
So if I had it to do over again, I would have ordered one of the leads from the battery a few inches longer so I could mount the charging connector to the original port area and probably done something more about a gauge. The BMS they used is a DALY 15s100a, there is probably someone here that knows what you can do about a gauge.
To be honest I haven't even pulled the lid off of the enclosure to view the work and test the individual cells. I will do that today. It is the wife's mower and she was anxious to get it going. :)


Here is the gauge on the batter:
1659789031372.png
1659789087909.png
 
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Does anyone here have the 115Ah (54”) mower? I’m interested in doing the LFP conversion eventually but wanted to see what others are doing for replacing the 115Ah batteries.

(FWIW the wear curves on the 115Ah Leoch batteries look a lot better than the 100Ah)
 
dochoot said:
I dropped in a 48v 100AH LiFePo4 battery from ampere time. https://www.amazon.com/gp/aw/d/B09BR4JZTT?psc=1&ref=ppx_pop_mob_b_asin_title
It fits fine in the tray and has it’s own BMS built in. I built some spacers to keep it secure in the tray form leftover plastic siding I had.

Is there any reason I can’t just use the ryobi charger that came with the mower? 48v, 13a.

I did order this charger just in case but would rather not rewire the plug if I don’t need to.


I did buy the new display module but haven’t tackled that yet. https://www.amazon.com/gp/aw/d/B088RG27LS?psc=1&ref=ppx_pop_mob_b_asin_title

Trying to keep it as simple as possible. Anything else I should be aware of so I don’t burn my barn down?
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I assume you added 4 x 12V Ampere Times? I am about to do the same thing on my Ryobi 54". Waiting for the parts to arrive. Is your conversion running OK? Any further comments/issues?
 
Nizadar said:
Well I've gone ahead and started my conversion process. I've purchased 4 CHINS 12.8V 100AH batteries from amazon.com (link here). I have a couple weeks before they arrive so I've got time to get the rest of what will be needed together. That's where you all come in :) I've got several questions!

First - top balancing (necessary step?)

Since each of the 4 batteries have their own cells and BMS I'll be needing to buy a 12V charger to charge each up individually. I've been watching Will Prowse on YouTube and this is what I believe he recommends. I've found a victron energy 12v/5a charger (link here). I don't necessarily care about charging speed since I'll only be using these to charge up to 100% before putting these batteries together into 48V. Good charger?

Second - 4 batteries 100% charged put in parallel (again is this a necessary step?)

What hardware (wire/lugs/etc) will be needed? To connect each battery together in parallel after charging each to 100% you connect each of the positives together and the negatives together (correct)? This is still a 12v battery at this point right? Do they automatically balance between each being in parallel or do I need to dischage/recharge them?

Third - 4 batteries 100% charged, top balanced, and put into series

I can wire each of the 4 batteries in series and create a 48V 100 AH battery. I'll then need a 48V charger to charge the battery. How does this charger look (link here)? Since this is for my lawn mower I don't really care about speed, but having 100 AH to charge I don't want it to take days upon days...


Sorry for the lengthy post. I've read this entire thread and learned a lot and I'm ready to start on my own "drop in" project. The SLA's the RYOBI used a total garbage. They replaced my initial set and upon unboxing and testing the best battery health I had was 66%. Sigh. I'm going to give them away or see about recycling them at a nearby place. I want my mower to mow... I'm tired of fighting the batteries. I want to solve the problem and get to using it as a tool.

Appreciate everyone's comments, thoughts, and opinions :) It's why I signed up for an account.
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About to start the same conversion myself using the same prepackaged batteries (Chins). I am no expert.

I plan to individually charge each battery fully with a 12V (nominal) Lifepo charger. Note sure if I am going to bother with the parallel balance.

I believe I will be able to use the original cables already on the SLA batteries to connect the Chins.
My understanding is that the 12V Lifepo batteries have a slightly higher voltage (13V+) When you connect them in series you are going to have a voltage of 52V+ - again, not an expert, but I think you might need a higher voltage charger. I picked this one - specifically made for 4 12V LifePo batteries in series https://www.amazon.com/gp/product/B07CXQBQ8D/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

Going to cut the charging plug off the Ryobi charger and put it on this charger.

Wish me luck!
 
RipRiley said:
Basically, I took measurements and asked a few questions on this thread and ordered it custom from the guy on the invoice.
It is working well. I am happy with it. Definitely much more power and longer charge. I'm charging it with a 5a charger I bought from the guy that built the battery $12.50. They actually sent the wrong charger...they sent a 220v and I ordered a 110v but I happen to have a 220v outlet for my air compressor so no big deal for me.
To install: all I did was take out the old batteries, pull off the dividers from the original tray (which are "glued" on), put the new battery in the tray (I had to adjust the ends to allow more room, but it is built to be adjusted), slide in the tray and connect the single anderson connector from the mower to one of the ones on the battery...doesn't matter which one. I then cut a hole in the upper housing to pull the other connector through for charging. If one of the leads was long enough I would have mounted it to the original charging port.
The original gauge lights up but is inaccurate. There is a gauge on the battery but I have lift the seat and pull the cover to view it. I'm sure there are options for bluetooth or other options. I'm actually going to look into that next.
So if I had it to do over again, I would have ordered one of the leads from the battery a few inches longer so I could mount the charging connector to the original port area and probably done something more about a gauge. The BMS they used is a DALY 15s100a, there is probably someone here that knows what you can do about a gauge.
To be honest I haven't even pulled the lid off of the enclosure to view the work and test the individual cells. I will do that today. It is the wife's mower and she was anxious to get it going. :)


Here is the gauge on the batter:
View attachment 105593
View attachment 105594
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Thanks for your reply! I reached out to Leo today using the email address on your quote/invoice above. Just asked him if he would build me one too. Once he replies, I plan to ask him:

1. Can he make the cables longer (maybe twice as long?) based on your feedback.
2. Can he ensure I get a 110v charger. 220 won't work for me
3. If he can add the Bluetooth module to the DALY BMS so I can communicate with it using my phone.

How is your quest for a battery gauge coming along? If you can open the battery box you might be able to add the DALY BT module yourself and use it with your phone and the app?
 
Like many people here I joined the site for this very topic. So thanks again for AMDPower kicking off this question and the work of the other contributors such as Ultrasoundjelly, Rio, bobbie_ohio, Jakeman, and others. The battery issue was top of my mind back in 2020 when deciding to go with an electric riding mower with limited options on the market at that time. I certainly had the concerns with the Ryobi RY48ZTR100 using the SLA batteries vs lithium, and my real world use mirrors others like the horrible meter never reading corrrectly and shorter runtime. However, I figured I could buy and replace the Ryobi twice over before I was even at the starter price of something lithum from Greenworks or the uber pricey Green Machine. It is great to see Ryobi and other manufacturers switching over to lithium solutions, but it looks like most have taken the same path as their power tools using proprietary battery packs vs drop-in form factors. Of course I can appreciate the flip side that forcing use of their own packs helps control standards and matching battery specs. Pros and cons I guess. Fortunately, I was able to get about 2 years of cuts out of the original batteries here in the hot Florida summers which is not to kind on any battery, but at least I don't have the freezing temps to deal with.

I have about another 9 months of warranty on the mower, but I don't really have the means to easily take it to a Ryobi repair shop if something breaks which sorta makes that pointless. I am likewise done with the junk SLA batteries. However, like many here I'm not looking to get deep into building my own packs vs leveraging the least intrusive drop-in solution in case I need to "rollback" to the SLA config if I need to sell the unit for some reason.

I already picked up the Camway meter to attach. I am likely to go with the latest 12v 100Ah Ampere Time batteries off of amazon even though the CHINS seems to be basically built about the same.

Where I ran afoul is making a bad decision to use a variable voltage Beleeb charger from Amazon (link) which said it would work with SLA/AGM and LiFePo4. I had the idea that I may be able to restore the batteries for more life, and if not have a flexible unit to charge and balance new LiFePo4 drop-ins. Unfortunately there is nothing that you set on the charger to distiguish the charging profiles and I doubt it works like they say for Lithium. However, it may not be any worse than trying to use the Delta-Q SC-48 charger that came with the mower.

The second problem was that I also purchased Beleeb's Ezgo tri pin connector to use with their charger thinking that I could reuse the mower charge port without cutting off and splicing my original charge cable (again for warranty/resell related issues). I knew I would have to bypass the lockout switch at some point for easy hookup to a charger. Well being a dummy I hooked up the Beleeb connector and no charge light indicators showed up. I plugged in my original SC-48 connector and the charge port LED lights up. I retry the connection on the Beleeb and nothing happens. I'm figuring it is the lack of the lockout pin being active preventing the LED from lighting. I retry the SC-48 and now nothing works there either. The mower won't even turn on now. No clicks or "thuds" from the lockout relay either. Again, this is just with the SLA batteries installed. Last night I checked the wiring of both charger plugs and discovered that the Beleeb pos and neg wiring are actually reversed polarity from the actual ezgo charger wiring on the original SC-48 charger. So I'm not sure if I shorted the charger, the batteries, or something else. It could also be that the old SLA batteries (which were run down anyways after my last mow) have now dropped below adequate charge which is why nothing lights up on the SC-48 anymore. More troubleshooting and testing on the electrical before I invest in modding the mower and investing in batteries. I'm going to use the electrical system troubleshooting guide kindly posted earlier on the thread.

My questions to the group are now the following:
1. Does anyone have any clear pictures of how they wired/connected the lockout wire to the positive terminal (I'm assuming the lead pos terminal was used)? I'm assuming that only the blue wire needs to be cut from the old tri-pin charge connector, a 5/16" ring crimped and attached to the terminal is the suggested approach? I see this being discussed but don't see any pictures, especially from the folks that did the drop-on approach. This of course assumes that down the road I just want to use a properly wired EZGo plug from a new LifePo charger to the existing mower charge port.

2. If I don't bypass the the lockout pin, has anyone found and used a 48v lifepo4 charger with an ezgo tripin connector? I have found a couple of products out there that have done this for golf carts but they seem really expensive.

3. If I don't want to bypass the lockout but still want to use a lifepo4 charger, it seems like the working solution is to wire everything the same as it came from the factory, but charging would require lifting the seat, disconnecting the anderson plug from the mower charger port and then connecting battery anderson plug to an anderson connection coming directly from my lifepo charger. Certainly not as elegant as USJ's 3D printed adapter, but seems the most practical.

4. All the notes I have seen said to not use the orignal SLA SC-48 charger and rely on the BMS. While the original charger approach seems to work for many here without issues that over time it will degrade the LiFePo4. Has anyone using the original charger with drop-in approach seen any degrading issues with their LiFePo batteries using this most simple approach?

Sorry for the length. Insights are appreciated. Trying to move forward one way or another since my mower is now 100% out of commission which is going to make mowing a real beast the more time that passes.
 
AMDPower said:
Hi. I'm new to the forum. I have a 48V Ryobi Zero Turn that runs off of (4) 100AH AGM batteries. It's been about three years and now I can't get through a full cut. I would like to upgrade to LiFePo4 batteries. I'm thinking of using these ones


It is my understanding that the 50ah LiFePo4 should be about equal to a 75AH SLA battery. The Ryobi also has a 75AH AGM model. So, my question is... Could this be a drop in replacement? I store it in my shed so I was going to monitor inside temperature and shut off the AC Circuit automatically when below freezing (this battery doesn't seem to have low temp shutoff). Also, if I pre-balance and wire for 48V, can I use the existing charger? I think it only outputs 48V so probably not. If not, can I use a simple 48V 50A or lower charger and charge them in series as they sit? Since these have built in BMS units will they handle the shutoff automatically? Many thanks for any direction.
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New to the forum as well. I am considering doing the same. Before I start I would very much like an actual wiring diagram of the mower. There is a charging circuit lockout that will not let the mower operate with the charger connected and under some other conditions. I am considering those same batteries you linked to, but the 100 ah version. Also considering them for my solar system. If anyone knows where i can get that Ryobi wiring diagram, I would be grateful.
 
ScudRunr said:
New to the forum as well. I am considering doing the same. Before I start I would very much like an actual wiring diagram of the mower. There is a charging circuit lockout that will not let the mower operate with the charger connected and under some other conditions. I am considering those same batteries you linked to, but the 100 ah version. Also considering them for my solar system. If anyone knows where i can get that Ryobi wiring diagram, I would be grateful.
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Try this:
diysolarforum.com

Ryobi Zero-Turn Mower SLA to LiFePo4 Conversion - (Updated - Build Complete With Pics!)

60 volts or so seems to be an inflection point for some electronic components before the next level. There is really no way to know without knowing the specs of the components. Perhaps Ryobi might know. My inverter manufacturer is real clear that 64 volts is the absolute battery maximum. Is...
diysolarforum.com diysolarforum.com
 
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"2. If I don't bypass the the lockout pin, has anyone found and used a 48v lifepo4 charger with an ezgo tripin connector? I have found a couple of products out there that have done this for golf carts but they seem really expensive."

I left the wiring as is, didn't bypass anything. I charge with either the original or a cheap lifepo4 10 amp charger. I added an Ezgo type connector to the lifepo4 charger:

Amazon.com : DIYOLFALL 48 Volt Charger Receptacle and Plug for EZGO RXV Golf Cart, 3-Pin Triangle Charger Plug Handle, OEM #604321 611218 : Sports & Outdoors

Amazon.com : DIYOLFALL 48 Volt Charger Receptacle and Plug for EZGO RXV Golf Cart, 3-Pin Triangle Charger Plug Handle, OEM #604321 611218 : Sports & Outdoors
www.amazon.com

Had to modify the charge port on the mower to make the new plug work. Don't know if there is an affordable plug that matches the original other than ordering one from Ryobi or Delta.

I have experienced 2 issues with my system, charging wise.

When connecting the lifepo4 charger to the charge port, there is a pretty good size arc that occurs. It is much better with the Ezgo connector than connecting with the original alligator clips.

After I left the lifepo4 charger connected overnight, the BMS tripped out twice while turning on the mower. After resetting the BMS the 3rd time, I left the key on and it worked fine. I have tried to limit the charge to approx. 80%, but I forgot that time. I have used a timer, which worked well. I never had this happen when charging below 100%
 
Jakeman said:
"2. If I don't bypass the the lockout pin, has anyone found and used a 48v lifepo4 charger with an ezgo tripin connector? I have found a couple of products out there that have done this for golf carts but they seem really expensive."

I left the wiring as is, didn't bypass anything. I charge with either the original or a cheap lifepo4 10 amp charger. I added an Ezgo type connector to the lifepo4 charger:

Amazon.com : DIYOLFALL 48 Volt Charger Receptacle and Plug for EZGO RXV Golf Cart, 3-Pin Triangle Charger Plug Handle, OEM #604321 611218 : Sports & Outdoors

Amazon.com : DIYOLFALL 48 Volt Charger Receptacle and Plug for EZGO RXV Golf Cart, 3-Pin Triangle Charger Plug Handle, OEM #604321 611218 : Sports & Outdoors
www.amazon.com

Had to modify the charge port on the mower to make the new plug work. Don't know if there is an affordable plug that matches the original other than ordering one from Ryobi or Delta.

I have experienced 2 issues with my system, charging wise.

When connecting the lifepo4 charger to the charge port, there is a pretty good size arc that occurs. It is much better with the Ezgo connector than connecting with the original alligator clips.

After I left the lifepo4 charger connected overnight, the BMS tripped out twice while turning on the mower. After resetting the BMS the 3rd time, I left the key on and it worked fine. I have tried to limit the charge to approx. 80%, but I forgot that time. I have used a timer, which worked well. I never had this happen when charging below 100%
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Thanks Jakeman!

Just so that I'm clear, when you hooked up the EZGO connector to your lifepo4 charger you could only connect the pos and neg and left the 3rd top pin for the signal lockout unconnected? If so, there are no issues with the lockout that prevent you from turning on the mower when hooked up tot he charger. So you can charge the mower without issues, but you only lose the safety feature of the lockout.

As far as the plug goes, I haven't tried contacting Delta or Ryobi for the same charge connector. I was able to use the one from Beleeb which has a slightly different shape but fit into the Ryobi without issues. Ryobi has that special "guide" in their port that would interfere with newer connectors that have the "Y" shape molded into the handle, but this one works fine. Unfortunately as my original post said, Beleeb wired their pos and neg backwards from the EZGO wiring. Regardless, if someone is just looking for a the tri-pin connector and doesn't mind reversing the wiring I will provide the link. The Beleeb provided plug had the benefit of already having an anderson SB50 connector on the other end. It would have been great if it wasn't for them having their wiring revered! However, it may be just as easy to try to order the OEM connector from Ryobi/Delta.

Beleeb EZGO Tri-pin connector
https://www.amazon.com/dp/B0B2PDYG3L?psc=1&ref=ppx_yo2ov_dt_b_product_details

I did just find on Amazon another outfit that is selling the Tri-pin connector without the internal "Y" moulding that doesn't have any wiring installed which may better.
https://www.amazon.com/Triangle-Cha...rds=EZGO+triangle+plug&qid=1661531622&sr=8-28
 
Kavalliero said:
Thanks Jakeman!

Just so that I'm clear, when you hooked up the EZGO connector to your lifepo4 charger you could only connect the pos and neg and left the 3rd top pin for the signal lockout unconnected? If so, there are no issues with the lockout that prevent you from turning on the mower when hooked up tot he charger. So you can charge the mower without issues, but you only lose the safety feature of the lockout.

As far as the plug goes, I haven't tried contacting Delta or Ryobi for the same charge connector. I was able to use the one from Beleeb which has a slightly different shape but fit into the Ryobi without issues. Ryobi has that special "guide" in their port that would interfere with newer connectors that have the "Y" shape molded into the handle, but this one works fine. Unfortunately as my original post said, Beleeb wired their pos and neg backwards from the EZGO wiring. Regardless, if someone is just looking for a the tri-pin connector and doesn't mind reversing the wiring I will provide the link. The Beleeb provided plug had the benefit of already having an anderson SB50 connector on the other end. It would have been great if it wasn't for them having their wiring revered! However, it may be just as easy to try to order the OEM connector from Ryobi/Delta.

Beleeb EZGO Tri-pin connector
https://www.amazon.com/dp/B0B2PDYG3L?psc=1&ref=ppx_yo2ov_dt_b_product_details

I did just find on Amazon another outfit that is selling the Tri-pin connector without the internal "Y" moulding that doesn't have any wiring installed which may better.
https://www.amazon.com/Triangle-Cha...rds=EZGO+triangle+plug&qid=1661531622&sr=8-28
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You are correct, no top pin. To be honest, I never tried to turn the mower on with the charger connected. I'm not sure why anyone would need to.

It charges perfectly fine, no matter which charger I use.

The battery swap has been a real game changer. The run time is so much improved that I get tired of mowing before the battery does!
 
Jakeman said:
You are correct, no top pin. To be honest, I never tried to turn the mower on with the charger connected. I'm not sure why anyone would need to.

It charges perfectly fine, no matter which charger I use.

The battery swap has been a real game changer. The run time is so much improved that I get tired of mowing before the battery does!
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Cool. Thanks for confirming. Which LiFePo4 charger did you end up going with again?
 
Kavalliero said:
Cool. Thanks for confirming. Which LiFePo4 charger did you end up going with again?
Click to expand...

That's the closest one I could find. Looks exactly like mine, except mine is marked 10 amp, but no model number on it. I didn't have to buy mine. when I purchased the battery I sent the Co. an email asking why a charger wasn't included. I did that because previous buyers received chargers with their batteries. They replied saying they don't include them anymore, but they'll send me one anyway. Told me it was a $120 charger. It works ok but has no special features.

Found this one, very similar:


Not sure I would've paid $120 for it when I could use the original on a timer
 
Jakeman said:

That's the closest one I could find. Looks exactly like mine, except mine is marked 10 amp, but no model number on it. I didn't have to buy mine. when I purchased the battery I sent the Co. an email asking why a charger wasn't included. I did that because previous buyers received chargers with their batteries. They replied saying they don't include them anymore, but they'll send me one anyway. Told me it was a $120 charger. It works ok but has no special features.

Found this one, very similar:


Not sure I would've paid $120 for it when I could use the original on a timer
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I appreciate the info. I'm still in troubleshooting stage with my original SLA configuration trying to understand which part of the system actually failed before I move forward with any conversion activities.

What I have discovered so far :
1. When I test the SLAs still in the mower I'm getting 49.9V when measured directly at the main battery connector. That doesn't really shock me since the SLA batteries were depleted after my last mow.
2. I get somewhere between 0-50mV when testing at the charge port terminals which indicates a bad charge port.
3. I get 49.9-50V when I disconnect the blue charge port connector and go straight to the battery with the main battery connectors together (per the electronic testing guide).
4. The 125A fuse is good.
5. The original SC-48 charger still works when I jumpered the charger plug to the blue charge port connector (battery side) per the electronic testing guide.
6. The mechanical switch click can be heard when turning the key but nothing shows the meter nor any other indication of power.
7. I was not able to get the charge port LED to light up to validate the lockout and charge port per the electronic testing guide.

All of this leads me to believe I have two separate problems:
1. The original SLA batteries are crap and likely too depleted to turn on the mower or any of the other mower electronics.
2. The charge port itself got nuked and is now bad for some reason which prevents me from using that. I will need to contact Ryobi about a possible replacement of that part if I am going to use that port in the future.

Can anyone on the thread confirm how they were charging their batteries while inside the mower when not going through the rear charge port?
1. Did you decouple the main battery connector and use a special battery charge cable wired with the same BMC2MS-gray connector? If so, did you custom make your cables or find something online already made?
2. If you were using aligator clips from your charger, were you disconnecting the main battery connector and clipping them inside the connector half attached to the battery?
3. Other approach?

Apologies for the ignorance on what was done here since I didn't see any reference pictures in the thread and it didn't sound like anyone has had the issue I ran into with a nuked rear charge port.
 
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To reduce or eliminate the spark have you considered a second power wire with a resister in it? Hook that up first to slowly charge any capacitors that will cause an ark, then connect your primary power charging cable. Then turn on your charger.

This is built into xt90 connectors like these:
FLY RC 5 Pairs Amass XT90S XT90-S XT90 Connector Anti-Spark Male Female Motor Adapter for Battery ESC and Charger Lead for RC Car Truck https://a.co/d/iMxOJjN

To reduce the charge from 100 to 80% have you considered getting a power supply that charges to a voltage of your choosing? If you could Guage how many amps you'd need you could slow charge it just to the perfect voltage and then with an active bms all the parts slowly gell to ideal... unless I'm missing something. I hope to have this setup someday with the mower hooked up to a sol ark 15k. I hope it's charge settings allow me to do this so I don't need another charger. Then during a power outage I'd switch the settings to faster fuller charge and push the batteries harder.
 
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Hi Guys

I am deep down a bad rabbit hole trying to convert my 54" Ryobi Mower from SLA to LiFePo.

I got the new batteries (Chins 100Ah 12V) Charged them individually, and installed them in the mower. I can confirm the series voltage is about 54V.

I turn the key on, get on click out of the main relay on the mower, then it turns off. Battery string voltage is instantaneously down to about 2.5 volts.

First time, I pulled everything out of the mower, disconnected the batteries from each other, and they all measured about 14V. Strung them back together got 54+volts. Put them back in the mower, hook everything up, still 54+ volts. Turn the key on one click, no power, back to 2 volts.

A couple of questions : When a LiFePo BMS shuts off due to will it automatically reset after a time (as long as no permanent damage has been done?
This seems to me to be an inrush issue with the mower, which sounds like really bad news for me. The batteries that came out of the mower are 115Ah AGM type. Have I made a stupidly horrible and expensive miscalculation here?

Appreciate any help at all.
 
Sracer42 said:
A couple of questions : When a LiFePo BMS shuts off due to will it automatically reset after a time (as long as no permanent damage has been done?
Click to expand...
It may depend on the BMS in those batteries. It may reset or it might take a small charge to reset it. The BMS protected the batteries so no worries on damage.
Sracer42 said:
This seems to me to be an inrush issue with the mower, which sounds like really bad news for me.
Click to expand...
I think that is exactly what you are seeing. If you can reduce the inrush by using a resistor as a prestart circuit that might do the trick. It is probably the capacitors in the motor controller if you have one. Otherwise the start up current for the motor if it has no motor controller. I had a similar problem with a chipper shredder. Thanks to advice I got here, I just reduced the voltage from 60 volts to 30 volts and it did not trip my 200 Amp BMS. I was reminded by a user here that a motor presents to the battery like a big resistor and the higher the voltage, the more current will flow in the circut.
Sracer42 said:
The batteries that came out of the mower are 115Ah AGM type. Have I made a stupidly horrible and expensive miscalculation here?
Click to expand...
No, I think it is recoverable in a number of ways. It depends on whether it has a motor controller of is a direct connection. keep us informed on your progress.
 
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