hi im new here. im currently working on a razor scooter that is electric powered. my setup is a 360w motor at 24v that is powered by razor scooter electronics that i bought off of the internet. my question is could my SLA's be done because it feels like there is no power at all to get it going anywhere. the SLA'S seem to be charging up to corrct voltage at around 27 volts. i have powered it before with only 2 14.4v battery packs in parallel without a speed contoller and it ran very nicely. is the problem that im describing be due to bad batteries? any input or help is greatly appreciated.
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Support V is for Voltage
If you say you ran it before with only 14.4V setup without a controller, and now you are running it at 24V with a razor scooter controller, then it is more than likely getting a limited amount of Amps from the controller. If you go from 14.4V to 24V (as long as all the components can handle to 24V) there should be a noticeable increase in speed.
Check your batteries after a full charge, ride the bike a bit then re-check them. Is there a large Voltage drop?? If not, the batteries are probably fine.
I dont know very much about Razor controllers, but I am sure we would need to know the specs on the controller etc.
If my experience is correct, there is something in the electronics that is limiting the Amperage and/or Voltage to the motor.
Dave ; Tennessee
XB-600.
it seems as if they hold a decenr amount of charge. i havent been able to take it for a ride because of its lack of power. if the voltage drops signifigantly, my problem is the batteries? and the thing about the speed contoller being a limiting factor is a possibility. the contoller is rated at 24 volts and the max amperage rating for it is 29 amps. the motor that i have is a 15 amp motor @ 24 volts. another question i have is if i add another 24 volts in parallel, would i get more power? becausei know doing that increases run time but im not sure of power
here is a picture of what i built. its a razor scooter clone with an extended rear end to accomodate a 7 inch tire, 3-speed bicycle hub acting as a jackshaft, and a 360w motor at 24 volts. it has a 6:1 gear ratio in middle gear but i have been riding it only in low gear which is at 7.5:1. im still fiddling around with the speed controller and battery setup on it trying to get it to run properly. other than that, it will be good to go soon.
here is a pic of my other project just for fun. its not an EV but it is what i had before i built this one
Could be bad SLAs. What is their history? How old, how many cycles, have they ever been left sitting discharged for long periods or deeply discharged?
And nice job btw!
not very sure of their history because i bought it off of someone off of another forum. but when i did recieve it, it looked like the negative battery terminal on the harness was completely fried. this might be an opportunity for me to go with a different battery chemistry. thanks for the comment.
If the batteries looked to be in bad shape, then yes, I would start by trying some other batteries.
Adding batteries in parallel may give it a SMALL boost and additional range, but for the most part, Amperage is what gives the motor more power and torque. You would have to increase the Amperage to the motor for power. Higher Voltage normally gives higher speed.
On most controllers there is some sort of current limiting circuit. You would need to identify it and modify it to get a big change in the power. Adding batteries wont hurt, it just wont give it a LOT more power.
Nice projects!!! Hope this helps and good luck !!
Dave ; Tennessee
XB-600.
what about higher Ah batteries? will they help. and about modifying the sped controller, what in particular would need to be upgraded to handle more or should i say put out more amperage. should i save the headache and get a whole new speed controller then? btw thanks for the good comments again.
Higher aH batteries will give you longer run time but not more power for hill climbing or acceleration. Here are the rules of thumbs:
Want to go faster? Raise the voltage to the motor by adding a battery in serial.
Want to go farther? Switch to higher amp-hour batteries or more batteries in parallel
Want to accelerate more quickly (or climb steeper hills)? Mod the controller or change to a controller that can supply more amps to the motor.
thanks for the advice. has anyone on this site modded a razor scooter controller for more amperage? id like to try doing that before i resort to dumping more money into this thing. btw, old_scoot are you on gopednation because your username looks familiar?
Yep. I'm there and on modifiedelectricscooters.com There are lots of modified electric razors over there, btw. Mostly E300s.
hey thanks. i just took a look over at modifiedelectricscooters and read up on the shunt mod for the speed controller. ill try it when i get some free time and ill update everyone on the status of this project.
so today i tried the shunt mod. i was able to find it under all the black stuff in the speed controller, which was the uninsulated thing that looked like a wire. i added solder to it to shorten the run of wire to it so there is a good amount of solder added to the shunt. i took it for a ride and it sure is more torquey than before and actually wants to go somewhere. but the problem now is that the curcuit breaker keeps going off everytime i get to the top of my first gear. my question is do i have a too high amp motor, which i shouldnt because it is only a 15 amp motor, or do i need to upgrade more stuff in the speed controller after doing the shunt mod, like higher amp mosfets or bigger cap?