afewskroosloose
10 µW
- Joined
- Nov 27, 2018
- Messages
- 6
Hi there. I am brand new here, this is my first post. If I chose the wrong section of the forums, please feel free to kindly kick me to where I should be. I have a project Im working on (and off). It is a 350-400lb 4wd zero turn all electric all terrain r/c platform built to do yard work, hauling, snow removal, etc...and obviously just for fun and to say I did it. Basically Im hoping it will be a greener, cooler replacement for my riding mower (I did ride the unit during testing and may add a seat?) mixed with an atv and big kids r/c car. The top speed is about 8mph, as I am more focused on pushing power and hill climbing than speed for this application. Telemetry and automatic obstacle detection and some interesting semi-autonomous stuff can be explored down the road (I bought the right controller, I think, if I wanna mess with it), but for now its just a glorified r/c tank that can actually run me over. I look forward to the strange looks from my rural neighbors when they see me rollin.
The idea is to build the base platform, then work out the add on attachments as I have time/the 'build fire' in me/and the funds. I have the base unit first cut built, and did a little on the ground testing with a 48v 18ah SLA pack, though Ill eventually go to lithium chemistry of some sort - 48v 50ah maybe for the traction drive base unit. Each side of the drive is powered by a 650w rated 900w peak bldc trike motor from Golden Motor - heavy and low rpm for easier final reduction and added weight. I picked a pricey Roboteq dual brushless 60v controller, mostly because there arent many dual reversing brushless escs that I know of on the market, and also because of the monitoring, pc connectivity and customization the controller allows, and as mentioned the ability for more advanced features to be incorporated down the road.
The unit has (4) 18inch diameter x 9inch wide rear mower wheels and 1" axles all around. I took a few pics with a yardstick to give an idea of the size - about 44" wide x 38" or so long. The frame is 8" high and the wheels are comparatively large so sans attachments, the unit is invertible just because thats cool. It also gives me decent ground clearance. I wont know if the motors are adequate until I can do some more ground testing, but the Roboteq should be able to handle up to 2kw motor per side if I want to upgrade. There are some 120ish dollar 48v sensored mid drive motors running around ebay in the 1.5kw to 2k range I could try down the road, though at 5k+ rpm vs the 1.1k of the trike motors, Id need another reduction stage and some redesign.
My initial ground test was very promising (its gonna be a brutish fun little toy, I think), but it became apparent pretty quick I had a drive train issue. I underbuilt the final #50 drive chain tensioners on either side and they werent up to the intertial forces of quick reversing and turning, etc. Shouldnt be too hard to fix so thats my next step.
In the meantime, I am working through and researching what options I have for tackling the higher powered attachments. They will have a separate battery from the drivetrain battery - I want the base unit self contained and able to be made somewhat water resistant with the drive battery enclosed inside the main chassis and well protected. As the attachment drives will require significantly more power than the traction drive, I can experiment separately with higher voltage (60, 72, 84, 96) motors, controllers, and battery packs to get to the desired kw outputs with lower amps - bringing the system into the range of lifepo4s and lithium ion safe/pack healthy discharge rates, rather than going to the more volatile and lower cycle life associated with Li-Poly.
(**disclaimer - I am an enthusiast, not an expert, and I welcome any and all input from those with more knowledge than I have - if I am mistaken, please fill me in - I wouldnt be a bit surprised if there were some glaring holes in my plan with the build. ES seems like it is a great place for folks of all stripes and levels to box around cool ideas**)
So I am in the 'design in my mind' stage of brushless motor/controller setups that may be suited for the 1.5kw continuous, 3kw often, and 7-10kw peak power ranges that I am thinking I should shoot for regarding the hungriest attachments like the snow blower and mowing deck (both in the neighborhood of 42"-50"). I may be shooting for unrealistic goals, but Im trying to get to 60-90 minute runtimes. I have hilly 6 acre property to mow, and 100yd+ long driveway to clear out the snow from. 45-60 minutes run time would most likely be adequate in most cases - I can always recharge and take two swipes at it.
**Now we come to the part where Id like to hear some thoughts on recommended setups for the high power systems.**
ESCs - Flier Model/APS HV esc, or two? Anyone know how these would hold up to use at roughly 1/3 of their claimed continuous/peak ratings? Kelly or Golden Motor bldc controllers meant for golf carts and motorcycles, maybe? Would it be hard to interface one of these larger ev controllers so that I had radio control of the throttle?
Motors - APS 80mm outrunner family, single or twin setups? Anyone know if an 80100 could handle 30-60 amps continuous for an hr at 72v with peaks of 100 amps thrown in? I really like the look of the Leopard 8072s and at 130 a pop, thats not too bad. They claim 4kw and high durability, so maybe a twin setup with these? Ive heard mixed reviews about the Revolt motors - but this seems like an application right in their 'wheelhouse'. How about Motoenergy/Golden Motor 3-5-10kw larger motors for traction vehicles? Im thinking this category may be best for duration of runtimes, heat dissipation capability, and overall durability? What about an SSS 56/114 "13kw" inrunner lower kv at high voltage, with entire can clamped in a machined aluminum mount block/heat sink? Obviously Id be introducing the need of a beefy gear reduction before Id be able to belt drive to my primary 'weapons'. Probably the complexity of using an inrunner would outweigh any cooling/efficiency benefits obtained, but I am not sure.
I can handle the mechanics and fabrication, I am just not sure about the power system I should be considering for reliable use at the 45-90 minute duty cycle I would like to get, and the electronics portions arent my strongest suit. Cost is an issue, of course, but I also dont want to cost cut myself into having to 'do it right the 2nd time' if it can be avoided. I will likely be piece mealing the big ticket items.
I cant make any promises on how often I will be updating the build progress - its been a pretty slow go so far, and well life happens. I also do metal art on the side and that takes up some time. Not to mention its tough to justify $500 plus drops on 'toys', sometimes. But...I am getting the 'fire' again and the gears wont stop turning. If I can swing it, I hope to start picking up the components for the first attachment build in the not TOO distant future, and would appreciate any advice, feedback, or discussion on any aspect, and especially help with power system selection.
Sorry for the long rambling opening treatise/salvo, but thats my project and Im stickin to it
Thanks,
Eli
The idea is to build the base platform, then work out the add on attachments as I have time/the 'build fire' in me/and the funds. I have the base unit first cut built, and did a little on the ground testing with a 48v 18ah SLA pack, though Ill eventually go to lithium chemistry of some sort - 48v 50ah maybe for the traction drive base unit. Each side of the drive is powered by a 650w rated 900w peak bldc trike motor from Golden Motor - heavy and low rpm for easier final reduction and added weight. I picked a pricey Roboteq dual brushless 60v controller, mostly because there arent many dual reversing brushless escs that I know of on the market, and also because of the monitoring, pc connectivity and customization the controller allows, and as mentioned the ability for more advanced features to be incorporated down the road.
The unit has (4) 18inch diameter x 9inch wide rear mower wheels and 1" axles all around. I took a few pics with a yardstick to give an idea of the size - about 44" wide x 38" or so long. The frame is 8" high and the wheels are comparatively large so sans attachments, the unit is invertible just because thats cool. It also gives me decent ground clearance. I wont know if the motors are adequate until I can do some more ground testing, but the Roboteq should be able to handle up to 2kw motor per side if I want to upgrade. There are some 120ish dollar 48v sensored mid drive motors running around ebay in the 1.5kw to 2k range I could try down the road, though at 5k+ rpm vs the 1.1k of the trike motors, Id need another reduction stage and some redesign.
My initial ground test was very promising (its gonna be a brutish fun little toy, I think), but it became apparent pretty quick I had a drive train issue. I underbuilt the final #50 drive chain tensioners on either side and they werent up to the intertial forces of quick reversing and turning, etc. Shouldnt be too hard to fix so thats my next step.
In the meantime, I am working through and researching what options I have for tackling the higher powered attachments. They will have a separate battery from the drivetrain battery - I want the base unit self contained and able to be made somewhat water resistant with the drive battery enclosed inside the main chassis and well protected. As the attachment drives will require significantly more power than the traction drive, I can experiment separately with higher voltage (60, 72, 84, 96) motors, controllers, and battery packs to get to the desired kw outputs with lower amps - bringing the system into the range of lifepo4s and lithium ion safe/pack healthy discharge rates, rather than going to the more volatile and lower cycle life associated with Li-Poly.
(**disclaimer - I am an enthusiast, not an expert, and I welcome any and all input from those with more knowledge than I have - if I am mistaken, please fill me in - I wouldnt be a bit surprised if there were some glaring holes in my plan with the build. ES seems like it is a great place for folks of all stripes and levels to box around cool ideas**)
So I am in the 'design in my mind' stage of brushless motor/controller setups that may be suited for the 1.5kw continuous, 3kw often, and 7-10kw peak power ranges that I am thinking I should shoot for regarding the hungriest attachments like the snow blower and mowing deck (both in the neighborhood of 42"-50"). I may be shooting for unrealistic goals, but Im trying to get to 60-90 minute runtimes. I have hilly 6 acre property to mow, and 100yd+ long driveway to clear out the snow from. 45-60 minutes run time would most likely be adequate in most cases - I can always recharge and take two swipes at it.
**Now we come to the part where Id like to hear some thoughts on recommended setups for the high power systems.**
ESCs - Flier Model/APS HV esc, or two? Anyone know how these would hold up to use at roughly 1/3 of their claimed continuous/peak ratings? Kelly or Golden Motor bldc controllers meant for golf carts and motorcycles, maybe? Would it be hard to interface one of these larger ev controllers so that I had radio control of the throttle?
Motors - APS 80mm outrunner family, single or twin setups? Anyone know if an 80100 could handle 30-60 amps continuous for an hr at 72v with peaks of 100 amps thrown in? I really like the look of the Leopard 8072s and at 130 a pop, thats not too bad. They claim 4kw and high durability, so maybe a twin setup with these? Ive heard mixed reviews about the Revolt motors - but this seems like an application right in their 'wheelhouse'. How about Motoenergy/Golden Motor 3-5-10kw larger motors for traction vehicles? Im thinking this category may be best for duration of runtimes, heat dissipation capability, and overall durability? What about an SSS 56/114 "13kw" inrunner lower kv at high voltage, with entire can clamped in a machined aluminum mount block/heat sink? Obviously Id be introducing the need of a beefy gear reduction before Id be able to belt drive to my primary 'weapons'. Probably the complexity of using an inrunner would outweigh any cooling/efficiency benefits obtained, but I am not sure.
I can handle the mechanics and fabrication, I am just not sure about the power system I should be considering for reliable use at the 45-90 minute duty cycle I would like to get, and the electronics portions arent my strongest suit. Cost is an issue, of course, but I also dont want to cost cut myself into having to 'do it right the 2nd time' if it can be avoided. I will likely be piece mealing the big ticket items.
I cant make any promises on how often I will be updating the build progress - its been a pretty slow go so far, and well life happens. I also do metal art on the side and that takes up some time. Not to mention its tough to justify $500 plus drops on 'toys', sometimes. But...I am getting the 'fire' again and the gears wont stop turning. If I can swing it, I hope to start picking up the components for the first attachment build in the not TOO distant future, and would appreciate any advice, feedback, or discussion on any aspect, and especially help with power system selection.
Sorry for the long rambling opening treatise/salvo, but thats my project and Im stickin to it
Thanks,
Eli