Controller question

[idontknowwatt]

I have a 36v 750 watt motor with a 36v 1000 watt 40a controller
What will my scooter act like with a 36v 750watt 30 amp controller
Will it be a lot slower or will it have the same top speed but just take much longer to get there
Or even a 36v 750watt or 500 watt 20 amp controller, If that’s possible?
I’m trying to get more distance out of my batteries, but not if I will have a 15mph top end as id like 20mph at least. Right now the thing will do 21 on a fresh charge in the dirt climbing hills and 33 on a flat surface. Yes I have it geared very low for climbing

 

[dogman dan]

Bottom line, the way to stretch range is to slow down. 36v will be slower than 48v, so you'd get farther down the road with 36v, or just riding slower than full speed with 48v. 48v x40 amps is nearly 2000w, so you'd climb the hills better with that. A 36v 30 amps controller would potentially put out about 1000w.


Since you don't want to be stuck with less performance, I'd say stick with what you have. Use it when you need to, but ride slower when your need is to go farther.

Spend money on more battery capacity to extend range, rather than downgrade performance.

 

[idontknowwatt]

 

[jamo96]

View attachment 1

Nice bike!! Did you make this or buy?

The battery box looks a decent size, I would think you could fit more than 12ah in there... What battery were you thinking of?

 

[idontknowwatt]

It started out as a mongoose cx24v450, I simply cut the frame and opened it up a few inches to allow for a larger battery box then cut the plastic so that it would fit nicely around said battery box. The batteries are lifepo4s and 12ah is all that will fit in it, that is unless I put one of those extended bottom bracket crankshafts in which case I will be pedaling the thing bow legged but have a wider battery box, screw that. I was thinking I might hide another 10ah of batteries under the seat and behind the side fairings but that’s a joke too because what the bike really needs is a nice 40ah of lifepos but there is simply nowhere to put them. I am extremely frustrated with the whole affair, maybe 10 years from now battery technology will advance to the point that 40ah of something comparable to the lifepo4s will fit in that 12ah of space I have now, I hope so because what I’m not going to do is destroy the bikes current ascetics by putting ugly battery packs all over it. It does look kind of cool, to bad in runs out of power after five miles because to me that makes the bike a hunk of trash practically

 

[idontknowwatt]

I love how quiet and smooth my electric bike is, I immensely enjoy bringing the front wheel off the ground and keeping it there just from throttle response and climbing pretty dam steep hills is a kick in the ass too. None the less I’m sorry to say “ Most especially on this site “ that electric bikes suck. Give me an electric bike with a miniature nuclear power plant and or a battery thats got 100ah that will fit in my current 12ah of space and I’ll be sold.
Now with that said please understand that I am fully aware of the fact that posting a picture of what I’m currently trying to build / duplicate on an e-scooter website Is nothing less that sacrilege and blasphemy but here goes, blackball me from this site forever if you will.

 

[idontknowwatt]

Currently I have the frame, the engine, the exhaust and 20in tires and rims W / disc brakes front and rear

 

[Kingfish]

Beautiful potential! I'm inspired! I guy could make a mint just selling the frame, body, and linkage - then leave the rest to the ebike integrator :wink:

Charmed, KF

 

[jamo96]

The batteries are lifepo4s and 12ah is all that will fit in it, that is unless I put one of those extended bottom bracket crankshafts in which case I will be pedaling the thing bow legged but have a wider battery box, screw that

What are the dimensions of the battery box? Are you using the stock battery?

You said you were using 36V, just as an example you could use 6 x 6s 5Ah Lipo packs for 12s 3p pack which would be 15Ah and be about 150mm x 150mm x 100mm in size... which is a pretty small footprint.
http://www.hobbyking.com/hobbyking/store/__9176__Turnigy_5000mAh_6S_20C_Lipo_Pack.html

Though there would be some overheads for wiring...

 

[idontknowwatt]

Indeed, I was thinking along similar lines, right now you can purchase the frames from the same place that’s making these bikes but they want like $2,700 for it but by closer examination of their design changes to that xr50 frame it looks like a piece of cake to me hell I’ve got access to a Mig, Tig and an arc welder at a friends shop. I contacted the company hoping to get a few answers on some basic questions from them but they are “ Or the person I talked to was “ a stuck up jerk wad. He did tell me however that since they began to market these things that they are swamped with orders for them to the max and that they are currently meeting with a number of Chinese companies for the purposes of having them making the frames / bikes hoping to be able to bring the prices down substantially. All I know is I want one and that just as you stated it would be an easy sell, everyone I know that’s seen these things wants one. Just a few minor frame changes and their patent won’t matter I just wish I had the cash to jump on this idea.
If anyone reading this would like to do so, I’d love to work for you please get in touch with me and lets get rich together.

 

[idontknowwatt]

The battery box was originally designed for 3 SLA batteries 12v 12ah stacked on top of each other. On top of them inside the box ( It has ventilation ) Is the controller. I forget the exact dimensions inside but that should be easy enough to figure out if you want the exact number. 4 X 3 plus 2in or ? / 15 or 16in tall etc.
I don’t know the specifics on all the batteries 3.2v each or whatever, I just contacted the people at YXM I believe it was, told that how much space I had and told them to make be a 36, power pack that would fit in there with the controller with as many amp hrs as would fit

 

[idontknowwatt]

ok new battery box now and more ah under the seat which gives me 20ah total, LiFepo4s, the old ones must have been trash because man this thing keeps going and going and going. I love my LiFepo4s.
In any event with how easy it is to forget to turn the power switch off going to the controller and how many stories I’ve read here from people doing just that I was thinking of putting a 36v little light on the thing that will light up ( obviously) only when the switch is turned on.
Will that work? Or will it quickly burn out due to the amps that will travel through it? If so maybe a resistor of some sort would take care of that?
My user name tells the whole story, idontknowwatt