Need help with Ryobi 480e that won't power on

[ElectricRider]

So long story short (literally), I replaced my batteries with 100aH LiFePo4 batteries and installed them fully charged. It worked as great at cutting my lawn as it had with the lead acids. My problem began when I accidentally shorted my charger (LiFePo4 specific) while it was charging my mower. Big spark at the charger from split second short. I unplugged the charger from the mower and turned the key on to test it. The Charge "Fuel" Gauge lit up then went dark within a couple seconds like it was draining capacitance. So I've been testing parts trying to figure out what burned out using the great troubleshooting guide I found on this site. I'm using the Block Diagram and Control Flow diagram to try and move down the 48v power path. Here's my testing results:

Batteries Tested like new (which they are) 53.2v
Anderson and blue connector 53.2v, main fuse is fine
Charge port Switch on, lights turned on but don't light, Jumper test failed (no green charging light) no relay clicks

So it seems like a charge port issue which I guess make sense since it would be the first thing in line to take the hit from the short. I'm wondering why a failed charge port would make the entire mower unusable. Is it the lockout? The battery temp thermistor? Or the charge port itself? Of course parts are hard to get these days and are on back order so I'm trying to find a workaround while I wait for them to come in. I tested further down the path and found the DC converter (and fuse) and the relay work fine as did the headlights when I applied 12v. There is no power reaching the key so this also indicates a problem upstream.

I may be wrong but I assume the port itself wouldn't cause this issue. My guess is that the failure is the lockout. So does anyone have any ideas on how to trick the lockout (or maybe the thermistor) into allowing power to the rest of the mower? If I could at least kluge a way to mow the lawn in the interim I'd save myself a lot of grief. The lockout has a connector with a blue wire that connects to the charge port and a second connector with a red, yellow and black wire that goes into a big corrugated sleeve so I can't tell where it connects to. I think it goes to the control panel and/or the DC converter. I don't think the lockout blocks power to the control panel entirely because if I remember correctly you could turn the power on while charging and the Power Gauge would light up but the mower wouldn't move or turn on the blades and it would beep.

Thanks for any and all ideas in consideration to my dilemma. If you happen to have a charge port and/or lockout on hand I'd be happy to buy it from you. Also, I may be way off base in my troubleshooting so let me know if you come to a different conclusion and why.

Thanks!

 

[MowerMike]

I would start doing continuity checks to see if any wires or connectors are damaged and have become open circuits. Also, there may be inline fuses that are blown.

 

[ElectricRider]

Thanks MM. That's basically what I've been doing and the two fuses that I know of are intact. The fact that I get no power at the control panel, and especially the key, makes me wonder what is most likely to cause this symptom besides the fuses? I wish the troubleshooting manual gave some detail as to what each part does. Some are obvious but others are unclear. Does the lockout cut off just the charge port or does it also cut off the battery from the control panel? Also, like I said in my OP, I have 48v to the Adnderson and the blue connector but can't locate it anywhere else. So what is the next component in line where I should see 48v? That's where I get confused with how the cutoff fits in. The block/control diagram shows the charge port, lockout and battery temp sensor are the first components after the battery and main fuse but come before the key switch and fuel gauge. I'm not seeing 48v at the key or fuel gauge so that make me think that the chargeport/lockout/temp sensor would be the smoking guns. Does that make sense?

 

[Fourdoor]

Off topic:

When I had a problem I could not find any help for troubleshooting or repair, can you link to the troubleshooting guide?

Thanks,

Keith

 

[sgkent]

or post the schematic?

 

[ElectricRider]

I'll post a link to the post that links to the guide in order to give credit where it's due.

Post with link to 480e troubleshooting guide

It's really a great guide. Good luck with your troubleshooting. I'll be sure to post my resolution assuming I get there. ?

 

[ElectricRider]

I'm back and happy to say that my problem is resolved. As I suspected the issue was a failed charge port. Luckily I was able to find someone that had it in stock. It included the Temperature Sensor but I used my original one. I'm also using the original Lockout so that part was still good as well. I hope this helps someone else with their problem even if only by pointing out and linking to that great troubleshooting guide.

 

[Mowitor]

I had to join after reading your post. My first post. I had almost exactly the same thing happen 2 days ago on my 480e, down to the capacitance drain at the key panel and complete dead system. Mine was totally my own fault when I was checking voltage at the charge port and left the red lead plugged in to the 10A fused port on someone else's DMM that I borrowed because mine wasn't available. Big spark! I tell you what, working on 48v systems with lots of amps is no joke. I've forgot to switch leads before but don't recall ever shorting anything because of it. Maybe because the only DC systems I've worked on is 12v or 6v or maybe my brain can't remember. I'm not a pro, just a DIY'r. I remember once getting a short when I left the setting on amps testing my truck's starter and never forgot that and never did it again. Anyhow, long story boring... I had the same exact suspicions as you and did same diagnostics with the same results. I have the shop guide and it mentions a "lockout" but doesn't explain any detail about how the lockout works. It's listed on parts diagrams and is connected to the blue wire like you explained. The guide does have a test routine for the temp sensor (should show 10K Ohms resistance) but I cant see anywhere to order one. I've tested the charge port but there is no continuity from the red power side. Just like you, I have no idea how the lockout works, what it's function is or how to test/troubleshoot the lockout vs the charge port. Very weird that the charge port makes the entire system unusable. Not sure if the charge port has any electronic complexity inside of it that is molded in or if the lockout somehow opens a switch that kills continuity. I'm curious if anyone knows how to diagnose if the problem is with the lockout and what its purpose is or if the problem is with the charge port besides confirmation after swapping parts as the OP did. Since ElectricRider resolved his with the charge port that's likely going to be my culprit but the charge port is about $100 and the lockout (whatever that does) is $20. Unless anyone knows a more affordable source.

 

[sgkent]

was the meter in amperage mode? That is usually what happens.

 

[Mowitor]

was the meter in amperage mode? That is usually what happens.

Nope, it was not in amp mode. It was on DCV-200 (next level down is DCV-20). I know I've used my self ranging DMM on 12V systems with the red lead still on the 10A fused link without ever problems. Didn't even damage the DMM, just the mower. But I checked youtube after the zap and apparently this is a thing. Never knew this my whole life.