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Great point on the charge haha. I need to proofread my posts more. Thanks, I've changed those settings. Weird idiosyncrasy with the Overkill BMS is that it resets the SOC calculator when I change a parameter so I guess need to cycle the battery again to recalibrate it.

Hey guys, I built a 100Ah 16S LFP battery with an Overkill BS and put it into service 26 months ago in my lawnmower. Top balanced. Tested capacity at start was 101aH using a battery tester a 2-3A load over 32 hours. Stored in my shed at 50-90F all year round, taken out only to mow. BMS reports...

This is what I do. Charging at about 12 amps for 3 hours using the AIMS charger I get 50%->80% (30% change) SOC on my shunt monitor. I use a cheap mechanical timer and it works well. If you get smart timer you could trigger it remotely and have it charge the night before you mow when the...

Try testing the key switch using this method (page 22). Ryobi RY48ZTR75/100 Riding Mower Electrical Components Troubleshooting and Testing

I'm surprised and impressed that Ryobi is honoring the warranty with a non-OEM DIY battery mod.

Initial thoughts: So you're measuring 56v at the battery right now? Did you accidentally disconnect (or incorrectly re-connect) anything on the control panel? Does the BMS app report any errors?

This guy was ready to replace the SLAs after only 1 season. Looks like he's no stranger to LiFePo4 conversions, so I wont be surprised if he follows along this path. He also does a decent breakdown on the current state of the battery powered zero turn market.

That’s what I’m doing now. I find that charging for 2 hours at 12 amps gets me 30-40% charge, just enough for my mow. Interestingly I find that the BMS reported SOC drifts from what the shunt reads over a month or so. Charging to 100% syncs them up again.

Yeah, it's kinda cool that you can software-disable the charge and output. Though, it seems that the way engineers design BMSs is for them primarily to be for battery protection, and not routinely regulate the depth of charge/discharge. For me, it would be cool if the BMS would allow a max 80%...

Did you confirm the output voltage on a DMM? My guess is that it'll read 0, as your app shows the battery discharge is turned "off," probably because of the max Ah setting you put in. Click that toggle button while connected to the charger and it should start up. The AIMs charger is a smart...

You're correct. I noticed that when I was replacing the nuts with the nyloc nuts and corrected it. Thanks!

I opened my battery after about 5 hours of very bumpy mowing to check things out and I saw no loosening of bolts. I did build one #2 AWG interconnect with plans to replace my bus bars, but quickly decided that it's really not much better than the bus bars. Have a look at the picture: with the...

Me neither, but this is a great idea. I’m going to order these. Anyone have a line on some high gauge m6 ring terminal braided interconnects for cheap, or do I just need to bite the bullet and buy a hydraulic crimper and build them myself?

Here's data from my last battery discharge. Mowed the flat front yard first, then moved on to the steep slope of the backyard. Can you tell when the backyard mow started? Current is smoothed over 10 seconds or so. My battery is 100 Ah BTW. Interactive graph here.

Dude, ugh. I'm sorry. Let us know what you find on the post-mortem. :( Maybe it was just that one cell that kept going over-voltage?

Good question. I bought the 75 Ah version in May '20 for $3550 (got a slight discount because it was delayed shipping). I have 8/10 acre of grass to mow on a 15-18° grade (see pics). When I first got the mower I was fairly pleased with it. Full yard mow took about an hour and used 40-50% of the...

Glad you figured it out. Here's where I sourced my Anderson connectors: https://powerwerx.com/anderson-power-powerpole-sb-connectors

Forgot to mention the biggest challenges for me and how I addressed them on this build: making sure that the bottom middle hole lined up with the middle hole of the steel frame and then the mower did my best to center the steel frame notch in lid put the steel frame on, then put the bolt...

I've finished my build and successfully mowed my yard with the new battery. 100 Ah cells, 16s Overkill BMS. Mowed my entire yard 0.8 acre on 22° slope using 30% of the battery capacity (80% → 50% SOC). One nice thing: with the old SLA OEM setup the fuel gauge would swing 20-30% depending on...

Thanks for all the info. It seems like the AIMS power supply should have this built in arc protection, since it's just a matter of building it into the circuit. Perhaps you get what you pay for. Nevertheless, from a pure usability standpoint I think the best option would be using a schottky...

Thanks. Any chance a simple inline diode would prevent the battery from charging the caps?

Ah, so like this using a 20A panel mount Midnight breaker? What size resistor?

It's a different charger. I can measure capacitance with my DMM, not sure the range. Do you mean put a SPST switch across the leads to the charger to discharge any caps before I plug in the mower?

I checked it several times. Maybe it was SMPS caps discharging, but they fried the hell outta my plug.

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...

If you know your pack's capacity you can just enter that value as 100% without taking the pack all the way down.

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...

So it looks like based on page 41 shorting the wire harness across blue (Charger Interlock) and red (pos voltage) wires will result in the green charger light coming on and the mower locking out from moving. Has anyone successfully bridged those and maintained this function using the original...

Just wanted to share a couple 3d prints I made for my battery build that might help others. First is a mount for the 100A QWORK Battery Shunt Monitor. My model didn't ship with the acrylic holder so I modeled this one after the one that ships with some other-branded shunts...

Update on the AIMS charger. I contacted their tech support re: float voltages for LifePO4 and here is their reply:

Quick update. In my search for the best 48v charger for our situation I found this one that should work straightaway with the Ryobi charging receptacle: https://alliedlithium.com/products/lithium-battery-charger-w-oem-plug-ezgo-rxv-48v-15a Online details are thin, but I spoke with the tech...

These are all good points. Have you been able to find out what the charge and float voltage is for the Delta charger? If you let your battery charge up for ~12 hours, at what voltage do the cells top out?

The charger port wires are 14 AWG and the current output of the supplied Delta Q charger is 13A.

Ooh, just found this charger. Check out the data sheet, it's programmable via a serial cable to set Vcharge, Vfloat, and current as needed. It says potentiometer (or via PMBus Protocol on serial connection) for voltage. Current adjustable as well, but it might just only be via PMBus Protocol...

Has anyone thought about not using the bus bars, instead using large gage wires with crimp ring connectors? I know this is almost blasphemy in this forum, but many here are building batteries to sit in their basement, while we have the extra mechanical stress of hitting bumps and holes in an...