NightStorm
New Member
None whatsoever. The only enclosure in the box was the plastic wrapping around the battery.
Ryobi Zero-Turn Mower SLA to LiFePo4 Conversion - (Updated - Build Complete With Pics!)
- Thread starter AMDPower
- Start date
I've asked it before, but I'll try once more as it seems to be a small hole in an otherwise comprehensive thread.
Does anyone know how to retain the lockout function after replacing the ryobi charge port with an Anderson plug?
I know how to disable the lockout function (thanks #589) but not how to retain it.
In assuming the charge port closes a circuit, or some such, when the plug is in that prevents the main contactor from switching. I'll look into it in the next few days, but it's a bit above my skill and equipment level. Thanks!
Wowzers @NightStorm, you've cracked the nut. Be sure to document your time-delay circuit for all us still lost in the weeds without a mower.
Does anyone know how to retain the lockout function after replacing the ryobi charge port with an Anderson plug?
I know how to disable the lockout function (thanks #589) but not how to retain it.
In assuming the charge port closes a circuit, or some such, when the plug is in that prevents the main contactor from switching. I'll look into it in the next few days, but it's a bit above my skill and equipment level. Thanks!
Wowzers @NightStorm, you've cracked the nut. Be sure to document your time-delay circuit for all us still lost in the weeds without a mower.
NightStorm
New Member
I will do that, likely this weekend.
The mower is still apart while I await a very, very delayed Amazon order, finally arriving sometime today. In the meantime I tested my idea with some spare parts I've got here and it seems to work. The basics involve another relay (I ordered this one) and make use of the fact that the capacitors across the motor appear like a short circuit until a voltage builds up across them. I use this to keep the relay from engaging. When the key is turned on a resistor feeds voltage to the capacitors and starts to build up a charge. Once the voltage builds up the relay can engage to redirect the key to the coil of the main relay in the mower. The relay I ordered has an 86 ohm coil, so putting that plus 250 ohms (actually needs to be slightly less) in series ends up working out about right to keep the 54v of the battery to 13 or so across the relay.
Anyway, I hope to finish this up late today or tomorrow.
NightStorm
New Member
I worked on this a bit today but it has not gone well. I did but one test and the mower cycled on and off a couple of times and then nothing. The BMS must have cut out again. The Bluetooth app show the battery is in "Protect" mode and there is zero volts across the battery terminals. I've completely disconnected the battery thinking maybe it would then reset, but no-go, even hours later. The Bluetooth app is no help as it is not much more than a voltmeter, there are no options or controls present. I tried plugging in the charger but it also did nothing.
SignatureSolar is closed until Monday ... the grass gets yet another reprieve.
SignatureSolar is closed until Monday ... the grass gets yet another reprieve.
No chance you have a 48V power source is there?
Often, connecting to voltage resets the bms.
Often, connecting to voltage resets the bms.
NightStorm
New Member
Thanks, I was hoping for something like that when I hooked up the charger. I'm still on the original charger, so maybe something wrong with using that?
fixitbetter
New Member
Since you don't have any voltage at the terminals it's unlikely any smart charger will work. The typically need a voltage at the terminals (and usually around where the battery "should" be) before they will turn on. You could try a "dumb" charger. I used a lab power supply to send 48V to wake up my EG4 battery when it had discharged too far (45V I think). However, I had the same issue where my battery got stuck in protect mode and never came out. I had retried the dumb charger, but didn't get a positive response, let it sit for a few days and still nothing. Signature Solar ended up replacing it. However, since you have the "port" on your battery, maybe support can walk you through a way to reset the BMS. This is why the precharge circuit is so important on this battery. It does not like the inrush current and will cut on and off before it goes into protect mode.
Does you EG4 app still show voltage (including cell voltages)? Mine still read out the current voltage(s) and I could see them changing, but protect mode remained.
NightStorm
New Member
Thanks, odd design that it can lock you out of the battery. I'll call Signature Solar tomorrow to see if they can help me with the battery.
My app shows the following:
NightStorm
New Member
I got the BMS reset. As @fixitbetter noted, a charger won't do as they won't turn on without some nominal voltage to prove that a battery is present. Catch-22.
I thought I'd post the process for amusement purposes. Can you guess from the picture?
Here, in part, is what the photo says:
I thought I'd post the process for amusement purposes. Can you guess from the picture?
Here, in part, is what the photo says:
- Reassemble SLA pack
- Jumper the LiFEPO4 from the SLA with some nominal resistor (125 ohm, 25A)
- Observe 50.4v at the LiFEPO4 battery.
- Observe that it still does not reset the BMS
- .. but the charger should now be voltage satisfied, right?
- Plugin the charger.
- App shows BMS in "Charging" state.
- World order restored
fixitbetter
New Member
Nice job! I almost mentioned trying to use the old batteries. I'm glad you got it out of protect. I never tried connecting the smart charger as I figured the lab charger would do everything I needed.
NightStorm
New Member
Finally enough stuff came together that I was able to complete this seemingly endless project. The below is what I've wired up:
The idea of the circuit above is to use the capacitors in the mower to delay enabling a relay turning on and off the contactor in the mower. It seems that the key enables a 48 to 12v converter which then turns on the contactor relay. I don't know that the actual circuit in the mower is the way I have it above, it is just my way of thinking about it.
The key has 48v (52-56 actually with the LiFEPO4 batteries) on one side and that enables a path to the 48-to-12v converter. I disconnect the later and run it through a relay so that the 48-to-12v only gets turned on when the relay closes. In my wiring the key enables a path through a resistor (plus diode) that goes to the mower side of the contactor. When the key is turned on it slowly brings the capacitors up in voltage and eventually it reaches a level where the relay can fire. The purpose of the diode is to prevent the closing of the contactor from keeping the relay engaged (the other diodes across the relay coil is just good practice to keep the collapsing field of the relay from sending a reverse voltage spike into the circuit .. you will notice that Ryobi has one across the contactor relay coil). I've wired this up and there is about a 3-5 second delay after I turn on the key until the mower's contactor "clunks" into place and turns on the mower. When I turn off the key the mower shuts down immediately and then about 3-5 seconds later I can hear the relay that I added disengage.
The astute here may recognize a problem that I did not pre-think and rather found during testing. If you turn off the mower and then turn the key back on again prior to the relay turning off the capacitors in the mower won't have been brought back up to voltage and instead the contactor will immediately engage, look like a short to the battery, and the battery's BMS will shutdown. Argh. I am sure there is an elegant solution but I'm tired of working on this, the lawn has gotten too long .. for now I'm just going to be careful.
One other thing: in the above I show a 200 ohm resistor for the pre-charge leg. In my build I actually used 167 ohms 'cause I was cheap and ordered a 10-pack of 5w/500 ohm resistors. I put three in parallel for the "200 ohm" part (making 167 ohms) and two in parallel for the 250 ohm part that feeds the relay.
With that said, the parts I used are these:
Relay
Resistors
Diodes
With that relay you probably don't want to change the 250 ohm resistor much. The relay has a coil resistance of 86 ohms so the 250 ohm resistor makes the voltage across the relay max out at about 52 * 86 / (86+250) or about 13.3 volts.
FWIW I was hoping to use this relay instead of the DPDT one linked above. It is a 48v SPST relay, I experimented with it, but alas did not have on hand the resistor I'd likely need to make it work. As I said, the grass is getting long and the wife unhappy.
I like the second relay 'cause it has a coil resistance of about 1.25k ohms. The problem with it is that cuts in at some very low voltage, significantly lower than the 48v for which it is rated. In addition it cuts out at an even lower voltage, something on the order of 10v. This means it will need something on the order of 2-4k ohm resistor in series to drop the voltage enough to make it effective (I did not have that and observed it had like a 15-20 second on/off delay).
One concern I have is that I don't know what the current rating is for the key switch. Perhaps a painful lesson will follow.
If anyone is interested I can post pictures later of the actual hook-up. Right now I should get to work.
RhinocerosBagel
New Member
I finished my conversion (Ryobi ZT 75AH) and was able to run on the new battery setup for over an hour today, instead of about 5-10 minutes! The built in meter dropped from 100 to 70 fairly quickly and then stayed at 70 for about 45 minutes. Then dropped through 65/60 within a few more minutes so I stopped at that point.
I've read through a lot of this thread, has anybody figured out how to set it up so that the mower will refuse to turn on when the charger is still attached? My setup is a lifepo charger that plugs into the built-in triangular charger port. The pos and neg are hooked up but the top lead/pin is currently not connected to anything.
(I currently have a "remove before flight" type of tag that sits in the key hole, but given enough time someone other than me is going to remove it, get distracted, and drive away with the charger still attached. Other measures like sitting the charger on the seat also rely on other people remembering to do so.)
Also I noticed a few posts saying they couldn't power up after installing the new batteries. I found that the little white plug and the blue wire both need to be connected or it will not power up at all.
I've read through a lot of this thread, has anybody figured out how to set it up so that the mower will refuse to turn on when the charger is still attached? My setup is a lifepo charger that plugs into the built-in triangular charger port. The pos and neg are hooked up but the top lead/pin is currently not connected to anything.
(I currently have a "remove before flight" type of tag that sits in the key hole, but given enough time someone other than me is going to remove it, get distracted, and drive away with the charger still attached. Other measures like sitting the charger on the seat also rely on other people remembering to do so.)
Also I noticed a few posts saying they couldn't power up after installing the new batteries. I found that the little white plug and the blue wire both need to be connected or it will not power up at all.
Hey there, @RhinocerosBagel May I ask what batteries you ultimately went with, and can you expound a little on the blue/white wire thing? I am intrigued.
My biggest apprehension with the upgrade is the inconsistency of the pre-charge bypass requirement. Some people seem to require it and others do not, which has me feeling uneasy about the whole thing.
Thanks!
My biggest apprehension with the upgrade is the inconsistency of the pre-charge bypass requirement. Some people seem to require it and others do not, which has me feeling uneasy about the whole thing.
Thanks!
RhinocerosBagel
New Member
In the triangular plug that the old charger plugs into, the wires coming out are the big red&black wires for the batteries, then there's a little white plug with two small white wires, and a little black plug with a blue wire coming out of it. When you remove the battery tray you have to unplug these.
I'm not sure what the precharge bypass means, but I'm guessing it's where you have to trick the old charger into turning on when you hook up the lithium batteries. I bought a charger designed for these batteries, instead of using the old charger.
For the batteries I went with four of these.
Julie EVD
New Member
Good Afternoon Gentlemen. I too am about to drift down that "Ryobi zt480ex conversion to LiFePo4 rabbit hole." Not knowing much about the requirements, I good a chance and bought 4 of these https://a.co/d/hHRK7FE on the strength that they are listed for "Golf Cart" use. They can source Other similar batteries specifically exclude that application. These can source 100 amps, so I'm hoping that will be enough. EPOCH batteries has a kit for Ryobi (for a bit more) that can source 120 amps (200 amps max for 10 seconds) each in parallel, for a total of 200 amps continuous with a 400 amp peak https://www.epochbatteries.com/prod...ic-lawn-motor-replacement-lithium-battery-kit I think they get past the inrush issue on the drives with that extra capacity. Hopefully the ones I purchased will get past it with no issues (fingers crossed). I also purchased a charger https://a.co/d/0QVMtUu and a plug that should be able to use the original charge port on the Ryobi https://a.co/d/bvRRWt2 . I'm a stickler for staying with original designs. I want to keep the safety lockout with the cord installed (for whatever reason... probably obsessive compulsion).
That said, I'm leaning toward just replacing the batteries one for one (the measurements are slightly smaller than the OEM), and using the new charger after I confirm polarity from the charge port to the battery bank.
Am I missing anything? Am I about to experience a profound level of "you-just-wasted-$1,500-of-your-money" pain?
That said, I'm leaning toward just replacing the batteries one for one (the measurements are slightly smaller than the OEM), and using the new charger after I confirm polarity from the charge port to the battery bank.
Am I missing anything? Am I about to experience a profound level of "you-just-wasted-$1,500-of-your-money" pain?
NightStorm
New Member
I should think that your choices should work, but am new to this myself and far from an expert. Your location says "NY" so I don't know how you store your mower in the winter but be careful not to ever charge these batteries when the temp. dips below freezing. Doing so will likely ruin them. Some batteries have low-temp. cut-off to prevent this, many do not.
I went with a single 48v battery that I bought from Signature Solar, intrigued by getting a unit both with low-temp cutoff and with a 200A BMS. I've had to monkey around to implement a capacitor precharge that kicks in for the first few seconds the mower key is turned on, if I don't do this the battery goes into a "PROTECT" state that you can't get it out of w/o another 48v DC source. Personally I'd not recommend this battery 'cause it way too sensitive and goes into PROTECT state very, very easily. As such it is too easy to get stuck with a dead mower way a long way from a 48v power source (and no, the battery charger will not work to take it out of PROTECT mode). The battery has an app that connects via bluetooth but no controls in the app. (I suggested such an app enhancement t in a call to Signature Solar but that seemed to fall on dead ears).
Also, the stock 48v charger that came with the mower works with my battery just fine, my guess is it would work with yours as well.
Good find on the plug, do you know if it fits?
icenov
New Member
I use the standard Ryobi (DeltaQ) charger and it works fine, if a bit slow (10 A max I think). The Daly BMS disconnects once the high voltage set point is reached (about 57 V from memory).
Successfully upgraded my RM480e 38inch mower today. Did a test run yesterday and did the whole 1.25 acre yard with some large hills today. It's been dry so most of the grass was not thick but I completed the whole yard with 70 % charge remaining. I built my own 100 AH battery pack with an overkill bms. Did not need to modify anything else, stock charger works well, indicator lights still blink and all. Will have to see if I change out the rider charge indicator or not, tracking the charge with my Bluetooth on the phone seems like plenty for now. Will compile my pictures after I check all my connections and button it all up again. Thanks again to everyone who shared their journey on here, not sure I would have tried this if not for this forum. Time for a shower and a beer to celebrate, cheers!
I also just finished my RM480e battery upgrade. I built a 160ah battery with 16 EVE cells. What a journey it has been. I didn't know anything when I began and didn't even own a multimeter, let alone a power supply or crimper.
When I originally took the covers off the mower there was lots of grass clogged around the motor controllers so decided early on that I would leave the covers off. So it looks more like a battery powered go-cart than a mower.
I don't think I've got much original to add, except for that I used carbon conductive grease on all the connections and loc-tight on all the nuts to help with maintaining good connections.
I will perhaps just add a word of caution for all the inexperienced like me. Be sure to leave the battery unplugged when you make modifications to the charge wires (installing the resistor between the red and blue wires at the charge relay). I didn't do this and got a good zapping.
Thanks to all those who helped me along the way. Yippee!
When I originally took the covers off the mower there was lots of grass clogged around the motor controllers so decided early on that I would leave the covers off. So it looks more like a battery powered go-cart than a mower.
I don't think I've got much original to add, except for that I used carbon conductive grease on all the connections and loc-tight on all the nuts to help with maintaining good connections.
I will perhaps just add a word of caution for all the inexperienced like me. Be sure to leave the battery unplugged when you make modifications to the charge wires (installing the resistor between the red and blue wires at the charge relay). I didn't do this and got a good zapping.
Thanks to all those who helped me along the way. Yippee!
Attachments
I would love to see your installation.Finally enough stuff came together that I was able to complete this seemingly endless project. The below is what I've wired up:
View attachment 152732
The idea of the circuit above is to use the capacitors in the mower to delay enabling a relay turning on and off the contactor in the mower. It seems that the key enables a 48 to 12v converter which then turns on the contactor relay. I don't know that the actual circuit in the mower is the way I have it above, it is just my way of thinking about it.
The key has 48v (52-56 actually with the LiFEPO4 batteries) on one side and that enables a path to the 48-to-12v converter. I disconnect the later and run it through a relay so that the 48-to-12v only gets turned on when the relay closes. In my wiring the key enables a path through a resistor (plus diode) that goes to the mower side of the contactor. When the key is turned on it slowly brings the capacitors up in voltage and eventually it reaches a level where the relay can fire. The purpose of the diode is to prevent the closing of the contactor from keeping the relay engaged (the other diodes across the relay coil is just good practice to keep the collapsing field of the relay from sending a reverse voltage spike into the circuit .. you will notice that Ryobi has one across the contactor relay coil). I've wired this up and there is about a 3-5 second delay after I turn on the key until the mower's contactor "clunks" into place and turns on the mower. When I turn off the key the mower shuts down immediately and then about 3-5 seconds later I can hear the relay that I added disengage.
The astute here may recognize a problem that I did not pre-think and rather found during testing. If you turn off the mower and then turn the key back on again prior to the relay turning off the capacitors in the mower won't have been brought back up to voltage and instead the contactor will immediately engage, look like a short to the battery, and the battery's BMS will shutdown. Argh. I am sure there is an elegant solution but I'm tired of working on this, the lawn has gotten too long .. for now I'm just going to be careful.
One other thing: in the above I show a 200 ohm resistor for the pre-charge leg. In my build I actually used 167 ohms 'cause I was cheap and ordered a 10-pack of 5w/500 ohm resistors. I put three in parallel for the "200 ohm" part (making 167 ohms) and two in parallel for the 250 ohm part that feeds the relay.
With that said, the parts I used are these:
Relay
Resistors
Diodes
With that relay you probably don't want to change the 250 ohm resistor much. The relay has a coil resistance of 86 ohms so the 250 ohm resistor makes the voltage across the relay max out at about 52 * 86 / (86+250) or about 13.3 volts.
FWIW I was hoping to use this relay instead of the DPDT one linked above. It is a 48v SPST relay, I experimented with it, but alas did not have on hand the resistor I'd likely need to make it work. As I said, the grass is getting long and the wife unhappy.
I like the second relay 'cause it has a coil resistance of about 1.25k ohms. The problem with it is that cuts in at some very low voltage, significantly lower than the 48v for which it is rated. In addition it cuts out at an even lower voltage, something on the order of 10v. This means it will need something on the order of 2-4k ohm resistor in series to drop the voltage enough to make it effective (I did not have that and observed it had like a 15-20 second on/off delay).
One concern I have is that I don't know what the current rating is for the key switch. Perhaps a painful lesson will follow.
If anyone is interested I can post pictures later of the actual hook-up. Right now I should get to work.
So I am going through the same conversion just of the larger Ryobi ZT540e (RY48140) 54" Zero Turn
I currently have 4 of these batteries in the mower: https://a.co/d/dGAvjzA
(Note: "Ampere Time" is now "Li Time")
However I am also getting the "clunk" from the relay on start-up, seeming to trigger the BMS, taking me nowhere.
I get we can bypass this issue by creating a pre-charge circuit, but I for one can tell you...there's many people that would rather just sell the mower outright and buy a new one than need to add any custom wiring.
So for those out there who are looking for a true "drop-in" solution:
I think a big question that needs answered here is what kind of in-rush current are we dealing with here?
It is enough of a current that is tripping the short circuit safety of multiple BMS (according to other posts, ampere/Li time, EG4, etc.) at rather high currents (Ampere/Li Time Short circuit is 250A, EG4 is 350A).
There's a question to me where this isn't adding up, and correct me if I am missing something, but how are we tripping short circuit safeties in BMSs at or above 250-350A without popping a 125A (in my case on the ZT540e), fuse that sits in between the battery and the load?
I believe the answers to these questions can greatly help people make well informed decisions when considering any "drop-in" replacements to their lead-acid batteries
I currently have 4 of these batteries in the mower: https://a.co/d/dGAvjzA
(Note: "Ampere Time" is now "Li Time")
However I am also getting the "clunk" from the relay on start-up, seeming to trigger the BMS, taking me nowhere.
I get we can bypass this issue by creating a pre-charge circuit, but I for one can tell you...there's many people that would rather just sell the mower outright and buy a new one than need to add any custom wiring.
So for those out there who are looking for a true "drop-in" solution:
I think a big question that needs answered here is what kind of in-rush current are we dealing with here?
It is enough of a current that is tripping the short circuit safety of multiple BMS (according to other posts, ampere/Li time, EG4, etc.) at rather high currents (Ampere/Li Time Short circuit is 250A, EG4 is 350A).
There's a question to me where this isn't adding up, and correct me if I am missing something, but how are we tripping short circuit safeties in BMSs at or above 250-350A without popping a 125A (in my case on the ZT540e), fuse that sits in between the battery and the load?
I believe the answers to these questions can greatly help people make well informed decisions when considering any "drop-in" replacements to their lead-acid batteries
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 21,840
Fuses have time-current curves.
BMS makes fast current measurement.
Connecting larger inverters, people do blow class-T fuses and weld contactors.
Fuses and lead-acid batteries are nicely dumb things.
Maybe a big honkin' NTC from Ametherm would do the job. Also as dumb as rocks.
www.ametherm.com
Is 80A steady-state enough?
BMS makes fast current measurement.
Connecting larger inverters, people do blow class-T fuses and weld contactors.
Fuses and lead-acid batteries are nicely dumb things.
Maybe a big honkin' NTC from Ametherm would do the job. Also as dumb as rocks.
How To Select an Inrush Current Limiter
Choosing the right model of inrush current limiters for your current inrush limiting needs can be vital for any project. Learn how to select the right one.
www.ametherm.com
Is 80A steady-state enough?
Ok makes sense, that was one of my thoughts, the fuse is simply slower than the BMS, and when it was Lead-Acid...the fuse is simply too slow for the in-rush.Fuses have time-current curves.
BMS makes fast current measurement.
Connecting larger inverters, people do blow class-T fuses and weld contactors.
Fuses and lead-acid batteries are nicely dumb things.
Maybe a big honkin' NTC from Ametherm would do the job. Also as dumb as rocks.
How To Select an Inrush Current Limiter
Choosing the right model of inrush current limiters for your current inrush limiting needs can be vital for any project. Learn how to select the right one.
Is 80A steady-state enough?
a NTC Thermistor, if calculated properly, could provide near the same function as the pre-charge circuit and simplify that design so you don't need an additional relay/timer/switch, could be rather smart.
My problem is, I can't find good documentation on what the steady state current on the ZT540e would be (likely somewhat variable dependent on conditions and motor workload?). So I don't know for sure if 80A would be enough. Any time I look up anything on the ZT540e I find much more about its smaller cousins, RM480e, or ZT480ex, which while similar, I would think would have lower in-rush/steady state currents due to having at least 1 less deck motor.
To my original purpose though, for folks wanting to look for any feasible "drop-in" LifePo4 batteries, are there any on the market who's BMS would not trip on start-up and require in-rush protection?
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 21,840
Unfortunately, I don't think NTC can be paralleled. Needs all its material thermally joined. (PTC, for fuses, I think could be paralleled.)
So you need a big enough one. And by the way they run HOT ?
Some batteries have built-in inrush circuits.
I think some of the Signature Solar server-rack batteries may have.
The issue is whether it meets needs for any given inverter a customer uses it with. External inrush, people can do their own.
But motor likely has less capacitor than big home inverters.
So you need a big enough one. And by the way they run HOT ?
Some batteries have built-in inrush circuits.
I think some of the Signature Solar server-rack batteries may have.
The issue is whether it meets needs for any given inverter a customer uses it with. External inrush, people can do their own.
But motor likely has less capacitor than big home inverters.
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