Matching Battery to Controller Specs

[Reggie Curry]

Greetings, everyone!

So, I need assistance with the following here...

I've purchased a 3000w kit that came with the following for its controller specs:

1) 48v-72 60Amp. Max working voltage 86V.
2) Size: L212mm*W115mm*H55mm
3) Functions: Low Brake, Display, Throttle, Cruise, Temperature Sensor, Lock, 25KPH Limited, Pedal Assist Sensor.
With multiple protection features such as stalled, over-current, over-temperature, over-voltage, under-voltage, speed, lack of phase and so on.
4) Optional Function: Front Light With Horn, Regen.Braking

I'm in the middle of looking for a battery for this thing, but I'm not sure if what I've came across will actually match what's needed. Its specs are as follows:

Battery Voltage: 72V
Category: Li-ion Battery
Voltage: Peak - 84V, working - 72V
Power: 300W-3000W
Cut-off voltage: 54V
Max. discharging current: 100Amps
Max Continuous Discharging Amperage: 50Amps
Rated Discharging Amperage: 50Amps
Charging Current: <10 Amps
Charging Voltage: 84 Volts


If you guys need me to leave links for these two, then I won't mind, but would those battery specs be plenty good enough for the kit? This will be my first ebike project, so I don't wanna end up getting the wrong battery for this thing.

 

[ZeroEm]

Need to start with what frame do you have. How much room or were are you going to mount it at. Then with the space limitations you can start looking.

 

[Reggie Curry]

Need to start with what frame do you have. How much room or were are you going to mount it at. Then with the space limitations you can start looking.

I've got a 26" beach cruiser with a v-frame and a rear rack that can handle the weight of the battery that I listed, so I'll have it mounted there.

 

[ZeroEm]

People do mount it back there. A big battery on the rack will not make you happy. It's the weight so far back and the racks do not hold up. You can try it but a triangle battery in the frame is better.

I like 72V it not the norm for most bikes it's to fast so the 52v batteries have become popular. It's best to have your average speed as close to max speed of the motor as feasible. Everyone wants to go fast but it cost distance.

The next questions would be how fast and how far you want to ride and how much money is in your budget. batteries are the most important and the most expensive piece.

Your controller clams 60a, your motor will not survive that at 72v for to long. 4-5k watts.
52v at 60a would be over 3k watts.

I would focus on the Continuous Discharge discharge of the batter and try to do most of the riding below that.
Do not take all the advertising as real numbers.

We have a lot of talk about who to buy batteries from here is a link List of trusted and reliable battery suppliers

As far as 72v batteries would trust Grin. Most build or have batteries built to what they need and to fit there frames.

You can find cheap ones on line but it is a gamble, most put cheap cells that may or may not last very long they are mostly over rated for the power they can deliver.

by Reggie Curry » Sep 26 2021 11:46am

ZeroEm wrote: ↑Sep 26 2021 8:31am
Need to start with what frame do you have. How much room or were are you going to mount it at. Then with the space limitations you can start looking.

I've got a 26" beach cruiser with a v-frame and a rear rack that can handle the weight of the battery that I listed, so I'll have it mounted there.

 

[Chalo]

Do you know the kV (RPM per volt) of your motor? Depending on what that is, a 72 volt system could be a big mistake.

If it's trying to run at 75 mph, but you only have enough power for 45 mph, you will never be able to get decent efficiency out of the motor, or as much torque as you'd have otherwise.

 

[Reggie Curry]

People do mount it back there. A big battery on the rack will not make you happy. It's the weight so far back and the racks do not hold up. You can try it but a triangle battery in the frame is better.

I like 72V it not the norm for most bikes it's to fast so the 52v batteries have become popular. It's best to have your average speed as close to max speed of the motor as feasible. Everyone wants to go fast but it cost distance.

The next questions would be how fast and how far you want to ride and how much money is in your budget. batteries are the most important and the most expensive piece.

Your controller clams 60a, your motor will not survive that at 72v for to long. 4-5k watts.
52v at 60a would be over 3k watts.

I would focus on the Continuous Discharge discharge of the batter and try to do most of the riding below that.
Do not take all the advertising as real numbers.

We have a lot of talk about who to buy batteries from here is a link List of trusted and reliable battery suppliers

As far as 72v batteries would trust Grin. Most build or have batteries built to what they need and to fit there frames.

You can find cheap ones on line but it is a gamble, most put cheap cells that may or may not last very long they are mostly over rated for the power they can deliver.

by Reggie Curry » Sep 26 2021 11:46am

I've got a 26" beach cruiser with a v-frame and a rear rack that can handle the weight of the battery that I listed, so I'll have it mounted there.

Do you know the kV (RPM per volt) of your motor? Depending on what that is, a 72 volt system could be a big mistake.

If it's trying to run at 75 mph, but you only have enough power for 45 mph, you will never be able to get decent efficiency out of the motor, or as much torque as you'd have otherwise.

So it's best to just stay away from a 72v even though the motor's controller is rated to handle at least that much in power, or, if I still go through with buying one, just go with one that has less amps than the one I mentioned? Sorry if I'm not really understanding what's being said here lol. Trying to learn about this hobby as best as I can.

As for the questions asked here... ZeroEm, I'd like to be able to get to, at the very least, around 60mph, hence why I decided to go with the kit I bought after seeing videos and reading several reviews about it from various sites. Any more speed that I can get after that is just a bonus to me by that point. Distance-wise, I'm not really sure, though I say I'd like to be able to travel a whole 30-something miles before my battery needs recharging, and my budget is up to around $1200 in total (I've already paid $611 for the kit, so far). I'll be willing to spend a little more if need be for a proper battery should it exceed $600...

For your question, Chalo, I don't seem to have any information about that from the description of the kit. I've looked through every detail, and I don't see any listings about that. All I can provide is that the motor's apparently an ENC3000 48v-72v Brushless Gearless DC 3000w model and that it supposedly spins at 860RPM at 72v. You do seem to make a good point about what you said there. I didn't even take that into account...

Matter of fact, I think I'll provide the links so you guys (and anyone else that replies to this) can see what I'm trying to work with here:

Kit: https://www.aliexpress.com/snapshot/0.html?spm=a2g0s.9042647.6.2.d9c64c4dMDgBTi&orderId=8138963691386820&productId=32725948413

Battery in question: https://www.aliexpress.com/item/1005002768350847.html?spm=a2g0o.cart.0.0.41b93c00RqTYox&mp=1

 

[ZeroEm]

The shortest answer to your question is spend the rest of your budget on the battery and you will go as fast as you can for what you have.

With out knowing next to nothing about your motor, I can only make a ball park guess of 40-45 mph with a 72v battery.

I realize that you don't know really what you are asking. It takes planning the right parts and money to do it. Your asking to turn a 15 mph bike in to a light motor cycle. Mopeds do 35 mph. It's dangerous and expensive. The best bike tires are rated for 25 mph.

Chalo is asking questions about your motor so he can answer your question! If you can not answer then he can not do the math to answer yours.

I have some links for your next build if you want to build the fastest bicycle on the least amount of money.

Your links do not work, they ask me for a email address. Even if they did most battery suppliers can not be trusted. Its a gamble buying cheap batteries. List of trusted and reliable battery suppliers

Reading material:
what is the best combo for 50-60 mph
Building a 60mph electric motorcycle on a 26" bicycle frame
Building a 60mph electric motorcycle on a 26" bicycle frame pt2
* * * THE 60 MPH CLUB * * *

by Reggie Curry » Sep 27 2021 3:18am
So it's best to just stay away from a 72v even though the motor's controller is rated to handle at least that much in power, or, if I still go through with buying one, just go with one that has less amps than the one I mentioned? Sorry if I'm not really understanding what's being said here lol. Trying to learn about this hobby as best as I can.

As for the questions asked here... ZeroEm, I'd like to be able to get to, at the very least, around 60mph, hence why I decided to go with the kit I bought after seeing videos and reading several reviews about it from various sites. Any more speed that I can get after that is just a bonus to me by that point. Distance-wise, I'm not really sure, though I say I'd like to be able to travel a whole 30-something miles before my battery needs recharging, and my budget is up to around $1200 in total (I've already paid $611 for the kit, so far). I'll be willing to spend a little more if need be for a proper battery should it exceed $600...

For your question, Chalo, I don't seem to have any information about that from the description of the kit. I've looked through every detail, and I don't see any listings about that. All I can provide is that the motor's apparently an ENC3000 48v-72v Brushless Gearless DC 3000w model and that it supposedly spins at 860RPM at 72v. You do seem to make a good point about what you said there. I didn't even take that into account...

Matter of fact, I think I'll provide the links so you guys (and anyone else that replies to this) can see what I'm trying to work with here:

More reading:
How to calculate speed from motor kv/voltage
The exact meaning of Kv

 

[DanGT86]

Greetings, everyone!

1) 48v-72 60Amp. Max working voltage 86V.
2) Size: L212mm*W115mm*H55mm
3) Functions: Low Brake, Display, Throttle, Cruise, Temperature Sensor, Lock, 25KPH Limited, Pedal Assist Sensor.
With multiple protection features such as stalled, over-current, over-temperature, over-voltage, under-voltage, speed, lack of phase and so on.
4) Optional Function: Front Light With Horn, Regen.Braking

I'm in the middle of looking for a battery for this thing, but I'm not sure if what I've came across will actually match what's needed. Its specs are as follows:

Battery Voltage: 72V
Category: Li-ion Battery
Voltage: Peak - 84V, working - 72V
Power: 300W-3000W
Cut-off voltage: 54V
Max. discharging current: 100Amps
Max Continuous Discharging Amperage: 50Amps
Rated Discharging Amperage: 50Amps
Charging Current: <10 Amps
Charging Voltage: 84 Volts


If you guys need me to leave links for these two, then I won't mind, but would those battery specs be plenty good enough for the kit? This will be my first ebike project, so I don't wanna end up getting the wrong battery for this thing.

There are obviously a lot of design considerations regarding the entire bike as a system. But to answer your original question the battery specs do match your controller very well. There should generally be a little bit of headroom between your max recommended battery discharge current and the max controller current. Otherwise you are being hard on the cells. This battery pack is well suited to your controller at max output.

 

[E-HP]

I'd like to be able to get to, at the very least, around 60mph, hence why I decided to go with the kit I bought after seeing videos and reading several reviews about it from various sites. Any more speed that I can get after that is just a bonus to me by that point. Distance-wise, I'm not really sure, though I say I'd like to be able to travel a whole 30-something miles before my battery needs recharging, and my budget is up to around $1200 in total (I've already paid $611 for the kit, so far). I'll be willing to spend a little more if need be for a proper battery should it exceed $600...

You want to go 60 mph on a 35 mph budget.

 

[goatman]

With a controller limited to 25km/h :lol:

 

[Chalo]

I'd like to be able to get to, at the very least, around 60mph,

On a cruiser bicycle? You really don't want that, even if you think you do. 30 mph is too fast for a cruiser; 60 mph is too fast for anything with pedals other than an elite downhill racing bike. Even if you beef up your budget enough to make it feasible, at best you'll wind up with a bike that's unpleasant and unsafe to ride.

This is apart from the fact that the kit and battery you have specified won't do it. My rough calculations suggest you'll need more than 9kW at the wheel to hold a steady 60 mph on flat pavement. The system you linked to might be able to output half that much.

If you want motorcycle performance, use a motorcycle.

 

[LewTwo]

... I'd like to be able to get to, at the very least, around 60mph ....

Buy a motorcycle or a car