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.