My kick scooter project

[ElectricGod]

The fuse block arrived today so I made connections for the 20S2P battery packs and for feeding power back into the main power buss. I connected all +V wires together via an 8mm bullet connector. It was a tight fit to get 7 14awg wires in there, but it's a lot more compact than a screw terminal block and can handle 200 amps or more. Since it worked so well I did the ground wires the same way. I used 8mm long connectors. Coming out the the other side is 2 8awg wires to an XT90 connector. I should probably use bullet connectors and 8 awg wire, but I forgot I didn't have but 10awg wire so there's no point. I really don't think I need 8awg back there anyway. At 1C with 3000mah cells that's a total of 36 amps with 6 20S2P packs. At 5C that's 180 amps. There's no way, I'll ever pull current that hard. I used 10amp fuses in the fuse block or a total of 70 amps which is possibly what I would likely use as a maximum amount of current. Tomorrow I'll build the battery box.

 

[ElectricGod]

I got around to hooking up my 20S LIPO packs and spinning up the motor while on my scooter stand tonight. OMG! it was so fast and that was on my run down LIPOs!!! I can't wait to ride this beast! It feels like 40mph or more.

 

[shortcircuit911]

Looks bad ass man. I'm going to guess 44mph top speed.

 

[ElectricGod]

Looks bad ass man. I'm going to guess 44mph top speed.

hahaha...44.5 mph.

 

[ElectricGod]

More work done.

This is the power leads to the back deck. This is an XT90 connector and 10 awg wires.

I had to drill a second hole in the side of the box since the other hole was too small for two more fat wires. The lower right hole was original to the scooter and was never intended to hold three 12 awg feild wires, a hall cable and the rear lights cable which are all in the lower right area. The two new power wires had to go in a new hole. Since the power wires had to go around a fairly sharp curve to go into the hole and then immediately turn again, I thought some heat shrink would be good to keep the wires from possibly getting cut or chafed.

This is the power wires terminating in the power distribution blocks. The smaller wires are 14 awg for the internal batteries or for distributing power to other things. The clear box with a black bottom is the internal fuse block.

And some pics of the battery box with plenty of room for fans if they are needed. I left a small gap on the sides so I could put a layer of foam there to act as a cushion. It's about 3/16"

General battery box pics...

 

[torqueboards]

Wow... That's a lotta lipos Will the fans even work well with the hard plastic cover?

 

[ElectricGod]

Wow... That's a lotta lipos Will the fans even work well with the hard plastic cover?

18650 LION battery holders. There's small gaps between the packs for air flow. There's space for 280 cells at 20S2P. I'm going to try them for a while without fans. If I don't have any overheating issues, then I wont do the fans. People build 18650 packs all the time with far closer cell spacing and no air cooling. It will probably be fine without air cooling.

 

[ElectricGod]

Shunts are so large. I bought the bigger 200A shunt a few weeks ago, but it's almost 5 inches long. Then I found this really compact 200A shunt. It's 3/4" x 2". That's 1/2 the size of my 150 amp shunt. I'm going to tap some threads for set screws so that I wont have to use wire lugs and a bolt. I'll just put the wire in the hole and tighten the set screws.

 

[ElectricGod]

I built 2 5S R/C charger adapters. I've been using them all weekend charging my LIPO and LION packs 5 cells at a time. This is definitely NOT a fast way to charge! I set my charger to 5 amps, but I can't get more than 2.6 amps charging. I'm pretty sure the balance wires are limiting things to some extent. My charger has 2 channels, but they are not isolated so I can't use both channels on the same battery pack.

 

[ElectricGod]

The bottom of the battery box is effectively done. I need to cut a hole for the XT90 cable to go in the lower left bottom corner, but otherwise is mountable. I went ahead with making it big enough to hold all 7 20S2P packs. It's a little wider than the back deck, but I have maxed out my existing battery space this way. I probably should have gone with the 6 packs. LOL...greedy for Kw/h's!

 

[ElectricGod]

I'm still scrounging 18650 cells from laptop batteries. I haven't load tested any of them yet, that will come this weekend assuming the weather keeps improving. I have 4 20S2P packs full of cells so far or 160 cells. The battery box is coming along nicely. I need to do a little more work on the lid and it's good to go. I'm waiting for some security torx screws to get here and a few other minor parts and it's done. After that its just down to scrounging more cells.

 

[ElectricGod]

I got the other LIPOs today. I need to unsolder the protection boards and remove the kapton tape off of them and then build them into a new 20S pack.

 

[ElectricGod]

The lid was a pain to make It's a snug fit on the bottom which is what I wanted. Getting it to fit the bottom perfectly was time consuming to say the least. I wanted the lid pieces to all knit together so that took time and a lot of care to get it right. I wanted the lid parts to be snug fits so if I have to leave the scooter outside in the rain, water wont get in the battery box or be driven in by wind action.

Here's some more pics of the box bottom. I added 3 strips of foam tape so the box wouldn't touch the back platform which is covered with grip tape. IT will also create a small air gap so any water that gets trapped between the box and the platform can dry out.

The 4 holes are for the bolts that will secure the box to the platform.

 

[ElectricGod]

I got the LIPO cells 2 days ago for the third LIPO pack. They came with 1S protection boards that I had to remove first. Then I soldered the tabs together and inserted foam slips between each cell. No kapton tape adheres directly to the cells. The packs is wrapped in 2 layers of foam and then wrapped tightly in kapton. The bottom has 2 layers of foam and then it's covered in several layers of kapton. I added the power wires and then the 5S balance cables, directed all the balance wires to the centers of the cells and laid down a layer of foam over the battery terminals and taped it down. This left a narrow channel down the middle of each row of cells that was perfect for stuffing the extra little bits of balance wires. I then laid down the balance wires so they pointed outward and secured them with kapton. Then came another layer of foam on top of the battery pack and lots more kapton. I then folded over the balance cables and secured them and then more kapton to close up everything very securely and to make it as water proof as possible. I'm charging the pack right now. The power wires go down either side of that center divider foam piece. and are secured to it by a piece of tape. There is a foam strip that completely covers the center 2 rows of battery terminals and keeps the power wires away from them. The idea is to keep the power wires from wearing on the battery terminals and to also make sure they can't move either. This was my best solution.

 

[ElectricGod]

I got to take the scooter out for a ride today...finally...the torque I have now is really impressive. On flat level ground I can now go 40mph. I ran the test on my 3 LIPO packs as seen below. Sagging was a significant issue. The 3 LIPO packs were never intended to run the scooter by themselves so that's not a huge surprise. The motor and LIPOs got pretty warm. I'll need to work out a cooling system for the motor. It needs to radiate heat better. The LIPOs wont be a problem once the LION packs are in place. The LION box is done and mounted and hooked up. There's only 4 populated 20S2p packs right now, but I have more cells coming soon to fill the rest of them. The speed controller barely got warm. I think mounting it to the side of the battery bay was a great idea. All that metal makes a great heat sink.

This is the completed 20S2P LION battery battery box. I didn't connect up the battery packs that didn't have cells in them. There's no point...yet. The kapton tape around the edge of the box is to keep the lid and the box from adhering to each other and to protect the edges from dings to the paint until it fully cures.

 

[ElectricGod]

I built a new charger on a cheap ATX 400W power supply. It worked great until the crappy power supply failed. Ah well...so it goes. I have a 24 volt 20 amp power supply coming Monday.

 

[MrDude_1]

I built a new charger on a cheap ATX 400W power supply. It worked great until the crappy power supply failed. Ah well...so it goes. I have a 24 volt 20 amp power supply coming Monday.

ATX PC power supplies suck for making chargers. They're never even close to their ratings.
The two cheap ways to go are used server power supplies or name brand PC/laptop "brick" supplies.

The server ones are dead reliable, but a bit of a pain to work with.. and ugly.
The brick supplies are good, but you have to be sure you use a name brand one with thermal rollback and current limiting.. otherwise you can melt into a very "hoverboard" like fire.

 

[ElectricGod]

I built a new charger on a cheap ATX 400W power supply. It worked great until the crappy power supply failed. Ah well...so it goes. I have a 24 volt 20 amp power supply coming Monday.

ATX PC power supplies suck for making chargers. They're never even close to their ratings.
The two cheap ways to go are used server power supplies or name brand PC/laptop "brick" supplies.

The server ones are dead reliable, but a bit of a pain to work with.. and ugly.
The brick supplies are good, but you have to be sure you use a name brand one with thermal rollback and current limiting.. otherwise you can melt into a very "hoverboard" like fire.

This was an experiment to see if 4 of the DC-DC converters would provide enough current to charge my batteries. They worked fine, but the PC power supply died after about 20 minutes of load. I really didn't care if it lived or not. I'll have a 20 amp power supply today to use with the converters.

 

[ElectricGod]

The ATX power supply wasn't the problem...one of the DC-DC converters died and was shorting out the power supply. I had a bad mosfet which has now been replaced and it's back working again. The ATX power supply is lame. It says it has two 12v busses that are good for 12 and 14 amps, but I seriously doubt it. I'm using both busses. I have 2 DC-DC converters on each buss and then the 4 outputs tied together. Each converter is producing 82 volts. Each one should be able to deliver about 2 amps, but the ATX power supply is clearly not capable of delivering 8 amps despite it stating it can deliver 26 amps. As a result I can charge one battery pack at a time or else the power supply shuts down. Measuring the 12v busses with no load they show 11.8 volts. Under load, they drop to around 10 volts while charging a single battery pack. I'm waiting for the watt meter that will go on the charger so I can see actual current draw off the DC-DC converters. Right now I am watching the 12 volt lines. When they return to 11.8 volts, then I know charging has finished.

 

[ElectricGod]

The ATX power supply is faster than charging 5 cells at a time via the balance cables. At least I can charge an entire battery pack at once, but geez...I want to plug in the charger and basically forget about it until charging is complete. I have much higher current converters coming and the 24v 20A power supply should be here today. I could be back riding if it wasn't for charging!

 

[ElectricGod]

The IRF4110 mosfet is almost an exact replacement for the SUP85N10 mosfet that's on these DC-DC controllers. The IRF4110 can handle more wattage. I have since the last post burnt 2 more SUP85N10 mosfets and replaced them from spares I had. I'm running these DC-DC controllers pretty hard apparently. If I don't use the fans the heat sinks get hot really fast. If I continue to use these converters, I'll put 2 mosfets in parallel and use a larger heat sink. There's a diode on the other heat sink and it barely gets warmer than air temperature. At 48 volts and charging 4 8000mah LIPO packs at the same time, 2 of these converters worked fine with fans. Now that I am running at 82 volts for charging, 4 of them can barely keep up with a single battery.

 

[ElectricGod]

I have been thinking about my motor tempurature and read quite a few articles about motor cooling since my test ride. The motor says its rated at 60 volts and 2000 watts. At 60 volts that's 33 amps. At 72 volts that's 27 amps. To me it's too hot for the wattage I'm throwing at it. I know with my existing motor controller that I peak at 60 amps and generally run at 30-40 amps. The motor gets too hot to touch comfortably. I'm going to implement forced air and passive cooling. The motor has vent holes on either end. On the non-shaft end of the motor, I'm going to force air through the motor and out the shaft end of the motor via a 100mm 12v blower. I also purchased some 150mm by 20mm heat sinks. I'll put some heat sink compound under them and then use a couple of hose clamps to hold them onto the outside of the motor. Hopefully I can get a little bit of a curve into them to so they seat to the motor diameter better. I think between forced air and passive cooling, I should be OK again. The previous motor I was using was a 1500 watt motor and it ran hot after 10-20 minutes of full throttle. It never burned out, but then I wasn't pushing it either. I have several single fan temperature controllers for 12 volt fans. I'll implement one of those to manage the blower.

 

[ElectricGod]

Active cooling option...

I just bought some 1/4" copper tubing and a tube bender. I'm thinking of snaking copper tubing around the motor can and then use a PC liquid cooling radiator, fans and pump to push antifreeze around. The tubing will get a thin coating of heatsink grease on the side that touches the motor and then several pipe clamps will squeeze it all together and hold the tubing snug to the motor. I think that will provide more "active" cooling than will just a bunch of heatsinks on the motor can transferring heat via pure air convection. I'll try the heat sink strips first. It's a simple solution that requires no power. I have lots of free space inside the LION battery box. I bet I can put the radiator in the box, use air flow while moving and fans to transfer heat and then redirect the hot air out the side of the box so the batteries never get warm. HMMMM...a movable baffle could be used to direct warm air onto the batteries in the winter.

 

[ElectricGod]

I played with the copper tubing last night and 1/4" tube is just too large to bend the tight turns needed to make this effective. I need some 1/8" tubing like is used in refrigeration lines to make this work. I will be working on forced air cooling this week. That is something I can do immediately.

 

[ElectricGod]

I got a new back wheel, tire, tube and 54 tooth sprocket on it and was already running a 15 tooth sprocket on the motor with my old 64 tooth wheel sprocket. I was getting great acceleration with the 15 tooth/64 tooth sprockets or 4.27:1 so my hope was that I could convert some of that torque into speed. It didn't work so well going to the 54 tooth wheel sprocket and keeping the 15 tooth motor sprocket. The motor just couldn't deliver and was drawing tons of current at 3.6:1. I was just asking the motor for too much. My 3 phase wires got hot and I had to shut it down. I knew it was probably way too aggressive of a move in gearing, but thought I would try it out and see...well it was too much. LOL! I'm now running 54 to 11 or 5:1. I'll run there for a while which should give me great torque and then I'll bump down the ratio to a 13 tooth motor sprocket or 4.15:1 to get a little more speed than I had at 4.27:1. I was doing a solid 40mph at 4.27:1 with great acceleration. 5:1 is going to accelerate like a race car and then go 30mph. If that doesn't work out so well, then I'll go back to the 64 tooth wheel sprocket and the 15 tooth motor sprocket. I was pretty happy with that setup already.