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...
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...
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...
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.
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...
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%...
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.
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...
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?
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...
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...
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...
OK, I've been in google hell trying to find boxes that'll work. If I can find a box I'll build a battery. I'm not quite sure why but I'm adversed to a wood box....
https://www.batteryjunction.com/pelican-1556-air-case.html
Is there room for 10.57" height?
Also found this case...
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...
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...
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?
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...
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?
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...
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...
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.
@rio Thanks. Yes, I think I stumbled upon @Will Prowse 's infectious youtube channel a few years ago and really got excited about building a battery but I'm nervous about warranty and encasement issues. I'd considered 12v batteries with a x4 charger but couldn't find info on whether it's kosher...
Hey @Jack Potredi Great design! Thinking about how I could replicate your build, I have a couple quick questions for you:
Is the strut steel secured to the box in any way?
Do the strut rods hold the batteries down?
Where did you source the strut/rods and hardware?
Is the battery box only being...
@rio Did anyone go for this charger? Looking at the manual it does have a current adjustment knob 20-100% to avoid overloading the 14 AWG wiring.
I've been trying to figure out the best way to charge this guy for longevity. I just ordered 16 of the CALB 100 Ah cells. Planning to use the...
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...
@AMDPower and @rio Thanks so much for this thread. First time caller, long time listener. I have been planning a LifePo4 conversion of my Ryobi RY48ZTR75 since I bought it. Mowing my 1 acre yard on a significant slope has brought my AGM batteries to their knees over two seasons of mowing. My...
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.
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?