Electrec battery/torque question

Hello all,

I bought a used ElecTrec in excellent condition, but the power is a bit weak. The motor is 600watts, powered by two 12v 14Ah SLA, in series. Even when I put in new batteries, it has trouble on steep hills (the bike is 70 lbs, and I'm 220lbs). I want to increase torque. I don't need long hours, I live in a small town, but need more power on hills, of which there are many. Would different batteries make a difference? What would happen if I got a replacement batteries with a higher Ah rating, like 24v, 20aH? Would it fry the controller? Would I get more watts of power to the motor? Is there a power advantage to using a LiFePO battery pack? What about 4 SLA batteries (6v, >14Ah), like this one: http://www.atbatt.com/product/4839/sla/interstate/6v-14ah/battery.

Sorry, I'm not much of an electrician. Any help would be kindly appreciated.

Chris

More torque is not from bigger batteries. the controller controls the watt output regardless if it 10ah or 50 ah battery if they are the same voltage.

You might be able to go to 36v if the controller has 50v or higher caps in it.

You could beef up the shunt in the controler.

It would help if you post some pics inside of the controller.

Dan

Hi Dan,

Thanks for helping me understand better. The controller is built into the motor housing, but I don't think it's wise for me to take it apart until I get more info from the mfg. I sent an email to electrikmotion.com about how they recommend to do a torque upgrade on a bike from the ElecTrec / Lashout / Rayos product line. I'll post their response here when I get it.

I'll look up about modifying the controller on the forums here. Can you point to any good resources on the subject?

Found this resource. They recommend changing the gearing ...:
http://www.evdeals.com/Gearing.htm

cheers,
Chris

I'm not familiar at all about that particular type of motor, but a lower gear will make your climb up the hill work better, but slower. Slower all the time, not just on the hills.

More voltage, if the controller can stand it, will make the motor spin faster. So combining more volts with the lower gearing could work well. If your controller cannot tolerate 36v, maybe it can still take 6v more.

Too bad it's not easier to peek inside that controller, if you see capacitors inside labeled 50v, I wouldn't hesitate to run 36v. 36v, fresh from the charger is actually about 42-44v. The caps look like little soup cans.

Climbing really steep hills with an ebike is not what most are designed for, so you are far from alone in being dissapointed with the performance of 600w. Most of us that tackle steep hills with ebikes use 1500 watts or even more.

Amp hours is the capacity of the battery, like the size of the gas tank. The controller regulates how many amps flow from it, like the size of a carburator. Watts is amps x volts. So if you can increase volts by 25%, you'd have 25% more watts.

Realize this is an older thread but I'm curious if you ever ended up getting new gears to improve torque. I'm looking at a similar bike and have 8% and 10% grades on my way to work. If you did change which gears and how much did it cost?