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Discussion Starter · #1 ·
Hello I’m currently upgrading my mx350 to 36v. I am running a 36v 800w controller with a 36v 800w motor. I am running into issues in trying to use a 36v 12.8ah 10sp4 lipo battery from a e scooter. The issue I’m having is that after about 20 seconds of full throttle the motor cuts out even though the batter still has plenary of battery life. i think I’m triggering the LVC on the controller. I also have tried to use a 36v 500w controller and it last longer but only for about a minute. There are also 3 small wires (blue yellow and green) coming from the output plug of the battery if that helps at all.
I’m wondering if there’s any way to bypass the LVC and or do something to the battery to make it work for the bigger motor.

Sorry I dont know anything this is my first post and electric vehicle project
Thanks!
 

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Hey, i know a little about them. First what controller are you using?? I run a 36v 1000w controller for my 24v 500w motor. I always run more of a controller. Obviously mine is overvolted, so the equivalent of roughly 750w.

Also what is you discharge max and steady of the lipo pack??
 

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Discussion Starter · #3 ·
I’m using a 36v 500w controller. The only information the battery gives is “36v12.8ah-460.8wh” its a 10s4p. I have a 24v 350w motor that is stock with the bike and the battery lasts a little longer when that is hooked up. I feel like i need a battery with more AH or something to restrict the discharge rate of the battery
 

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13 amp hours I would say it's okay but you need to know what your discharge rate is, Lipos are very strange like that. Sorry thought you had a 36v.800w motor by the first post. Controller sounds good wattage for wattage. Definitely need to check into that battery's specs.
 

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Discussion Starter · #5 · (Edited)
All i know is that the battery was for a 350w motor. I’m thinking i should just get a new lipo battery so i can use the 36v 500w controller with the 36v 800w motor. If I were to get a new battery what kind should i get with what specs so i dont trigger the LVC?

I’m also thinking about putting a 48v 12ah battery for a 750w motor if thats at all possible?
 

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I'm only somewhat Versed in the Lipo or lithium ion community. As far as I know with 750 or 800 W should have at least a 14 amp hour battery. I think you said you have 12.8 which should be plenty for that 350 watt motor, unless the instant discharge is low. I think for 350w you can get away with 10 amp hour, overvolted is technically 525w, which 12.8Ah should still be good. It's all about that initial take off with the amp hour. I'm going to try to get a 20 amp hour for my overvolted 36v 800w motor.
 

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Discussion Starter · #7 ·
So you think a 36v 20ah battery with an instant discharge of 30A and constant discharge rate of 15A would be good for the 36v 500w controller and 36v 800w motor combo?
 

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As far as I know you should be good. I have been looking for 30amp instant discharge and 20-25amp constant. Not easy to find.
 

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500 ÷ 32 ÷ 70% = 22.321 Amps Max
22.321 x 32 ÷ 70% = 15943.57 move the decimal over three places 15.944 :) should work out 16 amps is what you would want to come up with 70% is the approximate efficiency of the speed control 😉
 

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Discussion Starter · #10 ·
500 ÷ 32 ÷ 70% = 22.321 Amps Max
22.321 x 32 ÷ 70% = 15943.57 move the decimal over three places 15.944 :) should work out 16 amps is what you would want to come up with 70% is the approximate efficiency of the speed control 😉
Thanks you for doing the math! So i need to find a lipo battery with at least 16amps contentious current? The one I’m looking at is 36v 20ah 30A peak discharge 15A continuous do you think that will work? Sorry all of the battery lingo is still a little confusing lol
 

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That lingo is Spanish but yeah that battery should be fine however you said you had a 36v 500w controller for a 36 volt 800 watt motor? You'll have a problem with that setup. You need at least a 1000 watt controller for that 800w motor. The master motor is 500 watts that an 800 watt controller would be fine. It'll work but not very well. I have been there I have done that.
 

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Discussion Starter · #14 ·
So i ordered a 36v 20ah battery rated for a 100w motor. I purchased a 36v 1000w controller that should be getting here tomorrow, ill let y’all know how it works.
 

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Discussion Starter · #16 ·
I aslo got a throttle with a key and digital volt reader. In total i would say about 180-200 battery and charger were about 150 dollars. I’m hoping my old 36v 800w controller went to crap because I was getting no response when i had all of my new components plugged in. My motor works along with my battery and throttle so common since tells me its the controller.
 

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That's a good guess. You could always run 36 volts straight to the motor, just to make sure it works. Just a few seconds. I put a fuse between 2 of the batteries, just have to remember there is no amps being regulated so you don't want to hold it on there too long but it'll we still use the motor is running and not burned up. Could put a switch in there too. How ever you want to set it up.
 

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I am terrible with electric stuff, But 36v X 20amps is 720 watts right for a 1000w engine, I would think one more 10 amp battery might help. Lipo batteries are just to expensive.
 

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Discussion Starter · #19 ·
So I’m having the exact same problem with the new controller. I think I have all new working parts.
My motor works when directly connected to the battery.
My throttle seems to work because its reading the battery from the controller correctly.
My battery works becasue i read 41v off the throttle volt meter
My controller relays click once unlocked however no power to the motor

I’m stuck idk whats wrong, everything is acting like it works however it is not giving power to the motor. please help!
 
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