Razor E200 gone Lithium

[mistercrash]

After the Razor battery charger failed to peak charge and over charged the SLA batteries in my son's stand up scooter, this is what happened.

I got those out of the garage and made a 7S6P 25.9V 9Ah battery out of left over Sony Konion 18650V cells. I JB Welded 5.5 mm bullet connectors and a 7S balance connector to the side of the scooter. The result works great, the top speed is pretty much the same but the torque and acceleration is much better than before as reported by my 8 year old boy. He reported a ton more range also compared to the 7Ah SLAs.

I cut the ribbing at the bottom to make room and put some 5.5 mm bullets on the controller.

The connectors JB Weld to the side

After equalizing all the cells, I joined them in 6P strings, fully charged each string and assembled into a 7S6P pack. Then a final balance charge as a whole pack to test the connections.

Some shrink

Even with the ribbing trimmed at the bottom, there's a tiny bit of bulging on the metal strap. Not enough to worry about it.

First recharge after running all afternoon.

 

[sk8norcal]

your kid is lucky!

hey, do you use bms for that pack?
i think those 24v controller cuts off at 20.5v ??
is it a good idea to depend on it for LVC ?
thinking of using 6s lipo on my scooter...
3.4v * 6 = 20.4v

 

[mistercrash]

I don't know if it's a good idea to use the controller's LVC but I'm doing it anyway. My son has a couple years of experience with high end RC trucks running on lipos and he knows very well that when the power goes down, STOP and go get it, don't try to bring it back on its own power. I made him understand that it's now the same with the scooter, when the power goes down, STOP, shut it off and bring it back walking beside it. I trust him to do it the correct way. So no BMS for this little pack.

 

[mistercrash]

just an update on this regarding the controller's LVC, my kid brought back his scooter walking beside it like I told him because he felt the power cut off. GOOD BOY! The lowest cell was at 3.18 volts. It is low but far from critical so the LVC can be used for 7S if the scooter is turned off as soon as the LVC kicks in.

 

[mistercrash]

After a lot of riding, the controller blew something inside. They are so cheap that there is no sense trying to repair it. Since I'm on the web ordering a controller, might as well go for an upgrade. So the scoot is going from a 250W 24V motor to a 350W 36V motor. From a 24V 30amp controller to a 36V 30amp controller. From a 7S battery to a 10S battery. Since the scoot will go faster, it has to stop better so the rear band brake won't be enough so I ordered a front brake with an extra brake lever and brake cable. A new hall effects throttle to replace the original throttle which is simply an on/off switch. A solid rubber tire for the rear wheel, no more flat tires in the rear since it's a PITA to get that rear wheel off. And finally a small 2amp 42V charger. The kid is excited, asks me when the parts are coming everyday.

For anyone interested in doing the same, here's a parts list ordered at electricscooterparts.com

- 200x50 ( 8x2 ) Solid Rubber Airless Flat-Free V-Style Street Tread Scooter Tire (TIR-8X2FF1)
- Speed Controller for Razor® Dirt Rocket Electric Dirt Bikes MX500 Version 1-9 and MX650 Version 1-7 (SPD-CT312C1)
- 3 Wire Standard Half Twist Throttle (THR-93)
- Front Caliper Brake With Brake Shoes (BRK-640)
- Right Side Brake Lever With Brake Switch (LEV-35)
- 35 Inch Brake Cable With 30 Inch Black Cable Housing (CBL-030)
- 36 Volt 350 Watt Electric Scooter Motor (MOT-36350)
- Battery Charger for Self Balancing Two Wheel Scooters (CHR-42V2A-LI-3PS)

 

[kmxtornado]

Sounds like a fun project. I'd love to see some photos and learn more about your experience with the new battery setup. Congrats on bringing up a good kid who knows safety! After my daughter (30 months old) putting a screwdriver to the charge port of my Cruzin Cooler, she now knows too. Scared the pants off my wife and me both when we heard and saw the sparks fly up 2' into the air but we all learned a lesson w/o a fire or visits to the hospital luckily.

 

[mistercrash]

Sorry but no pics for now, when I get busy doing something I often forget to stop to take pics. I did have to modify the scooter to make things fit. The motor is big so I had to cut off the piece of metal on which the kick stand bolted. So no more kick stand. I had to get rid of the original circuit breaker that was still there but was not used. I had to extend the slots for the brake shoes on the brake caliper to make the shoes contact the front rim. I had to re-position the on/off switch to make room for the bigger controller. This left a couple holes in the box where all the electrics are so when I open the scooter again to plug those holes, I'll try to remember to take pics.

The kid liked his scooter before, but he absolutely loves it now. He loves the smooth throttle control, the added torque and top speed. I will have to temporarily set up a GPS on the handle bars to find out what his top speed is now. It used to be 21/22 km/h.

 

[mistercrash]

Here are some pics of the 36 volt 350 watt conversion with front brake. I did take a pic when the goodies came in.

Then the ribbing at the bottom of the box I had to shave off to make room for the battery.

The holes left from the repositioning of the on/off switch, the circuit breaker that was taken off and a third one made for the Lithium conversion a few years ago.

Holes plugged as best as I could using some JB Weld for plastics.

The 10S6P battery made form 18650 cells salvaged from DoctorBass Makita tool packs. The cells were spot welded with a JP Welder.

A pic to compare the old 24V 250W motor to the 36V 350W motor.

The new hall sensor throttle with the front brake lever. Notice I make all the wires and cables go inside the tube.

The wires and cables exit the bottom of the handle tube and enter the chassis to again exit underneath to enter the box.

Front brake. I had to extend the slots for the brake shoes so they would contact the rim and not the tire. I need to get the optional aluminum front rim, this plastic one started to melt. lol

Ready to close this up and hand it back to the kid. He absoloobly loves this thing, did I say that already?

Thanks for watching
Ray

 

[mistercrash]

The first battery I made a few years ago that prompted the original post was made with what many have done in the past (I still see it done today), hot glue the cells together and solder the connections. This quickly failed before a single season of riding so I made a second battery using plastic holders for 18650 cells and spot welded the connections. That second battery held together well enough after more than three years that this time I simply added more cells to it. So this battery has physically held up beautifully, but I have not tested the capacity so I can't comment on that.

 

[mistercrash]

The front brake that I fitted worked but not as expected. Mostly because the front rim is made of plastic. I replaced the front wheel with the optional aluminum wheel and the scooter has very good braking power now. Item WHL-220F at electricscooterparts.com. New 10X30X9 mm bearings are needed for the aluminum wheel.