standfast
100 W
Well, back at it again building a few bikes. I finished my first e-bike in 2015. See it here. https://endless-sphere.com/forums/viewtopic.php?t=60191 It is still up and running. My original li-po battery is getting a bit sacked out with about 2600miles on it. Other than that, it has been very reliable and never let me down. Now I need to build some more bikes so the rest of the family (wife and 2 boys) can join in. My oldest who is 9 has been beaten his POS Mototec cheapy electric bike into the ground. I have fixed it like 20 times now from him jumping it. He has gotten to the point where he just leaves it WOT all the time. Time for something better. I would just buy an Oset, Kuberg, or whatever but they don't have the kind of range to do the trail/exploration riding that my bike does and the areas that we will ride require. I am looking for a bike that can go at least 30-40 trail miles or more. I think I can do it.
For this bike, I am designing it to use mostly pit bike components to keep the cost down and the the durability up. This allows me to use everything from cheaper China pit bike parts or any high end aftermarket parts for CRF50's, CRF70's, etc. if I need to get fancy with one. I need it to be a robust bike that can be dropped frequently etc and be bullied by adults because I am sure that will happen. I am building these bikes to be capable of growing with the kids as well. There are plenty of different fork lengths and wheel tire combos that are very affordable that can be swapped on.
I am designing as I build and receive parts. I hope to have the first one up and running to test in about a month or 2. This first bike will have a 12"/12" wheel/tire combo. It's big enough for me to ride it. For my younger son, I am going to use 10"/10" wheels with a much shorter stock crf50 sized fork. For my wife's bike, I am going to use a 14"/12" setup with a longer fork.
The first bike is going to use a smaller GNG motor seen here. https://www.gngebike.com/belt-chain-motor It is a 1500w motor that will be able to take about 3kw peak. This should be good for the 2 kids. This will also fit a longer version motor that has the same mounting which is what I want to use on my wife's bike. Probably the LMX motor or almost any of the motors from Senli magnet.
The controller will be a Kelly mini brushless. For the battery packs on the bikes, I am going to likely try a couple different things. For the small 10" bike, I am going to try running 2 56v (52V nom) EGO 7.5ah tool batteries in parallel for a total of 840wh. These are available at Home Depot which makes it simple. Plus I already have one for my lawn mower. This will not give the ultimate 30-40mile range I want but it will be good for testing and for my youngest boy to learn on. The upside is they have a factory charger and can be charged in an hour. I bet it will get about 15-20 trail miles or so depending on peak current setting. The other bikes will likely get 18650 packs. It will fit any pre-made packs sold by Luna Cycles that are single row. Like this one. https://lunacycle.com/triangle-52v-panasonic-ga-18650-24ah-pack-high-power-long-range/ or this one https://lunacycle.com/triangle-48v-panasonic-ga-18650-17-5ah-pack-high-power-long-range/. There are a bunch of others out there but I need to find out which are using legit cells etc. These packs will easily fit. I may also build a pack for them that utilizes all the space which will fit over 300 18650 cells if I want. I may also try a high discharge pack using 20 4s hard case packs for a 72v 20ah setup that can do 7-8kw. That should compete with almost any mini ICE bike out there. I really like this design as it allows easy access to the packs without really worrying about building a battery box to protect whatever I put in there. It's all built into the frame and sealed up water tight with a gasket on the seat clam shell.
I still have some more work to do designing and building the swing arms and more research on parts. Here is some pics of where I am at for now. I will try to update this as I go along.
For this bike, I am designing it to use mostly pit bike components to keep the cost down and the the durability up. This allows me to use everything from cheaper China pit bike parts or any high end aftermarket parts for CRF50's, CRF70's, etc. if I need to get fancy with one. I need it to be a robust bike that can be dropped frequently etc and be bullied by adults because I am sure that will happen. I am building these bikes to be capable of growing with the kids as well. There are plenty of different fork lengths and wheel tire combos that are very affordable that can be swapped on.
I am designing as I build and receive parts. I hope to have the first one up and running to test in about a month or 2. This first bike will have a 12"/12" wheel/tire combo. It's big enough for me to ride it. For my younger son, I am going to use 10"/10" wheels with a much shorter stock crf50 sized fork. For my wife's bike, I am going to use a 14"/12" setup with a longer fork.
The first bike is going to use a smaller GNG motor seen here. https://www.gngebike.com/belt-chain-motor It is a 1500w motor that will be able to take about 3kw peak. This should be good for the 2 kids. This will also fit a longer version motor that has the same mounting which is what I want to use on my wife's bike. Probably the LMX motor or almost any of the motors from Senli magnet.
The controller will be a Kelly mini brushless. For the battery packs on the bikes, I am going to likely try a couple different things. For the small 10" bike, I am going to try running 2 56v (52V nom) EGO 7.5ah tool batteries in parallel for a total of 840wh. These are available at Home Depot which makes it simple. Plus I already have one for my lawn mower. This will not give the ultimate 30-40mile range I want but it will be good for testing and for my youngest boy to learn on. The upside is they have a factory charger and can be charged in an hour. I bet it will get about 15-20 trail miles or so depending on peak current setting. The other bikes will likely get 18650 packs. It will fit any pre-made packs sold by Luna Cycles that are single row. Like this one. https://lunacycle.com/triangle-52v-panasonic-ga-18650-24ah-pack-high-power-long-range/ or this one https://lunacycle.com/triangle-48v-panasonic-ga-18650-17-5ah-pack-high-power-long-range/. There are a bunch of others out there but I need to find out which are using legit cells etc. These packs will easily fit. I may also build a pack for them that utilizes all the space which will fit over 300 18650 cells if I want. I may also try a high discharge pack using 20 4s hard case packs for a 72v 20ah setup that can do 7-8kw. That should compete with almost any mini ICE bike out there. I really like this design as it allows easy access to the packs without really worrying about building a battery box to protect whatever I put in there. It's all built into the frame and sealed up water tight with a gasket on the seat clam shell.
I still have some more work to do designing and building the swing arms and more research on parts. Here is some pics of where I am at for now. I will try to update this as I go along.