Multi-use Battery for Different Voltage Hub Motors???

[OverflySportsmanXY]

I have an opportunity to build two different ebike conversion kits (one with a front wheel 36V 350W motor and the other with a rear wheel 48V 500W motor). Given the opportunity, is there any way I can purchase a single battery pack (and an additional battery cradle) and be able to swap a single battery between the two bikes? With the higher cost of batteries I wondered whether other less costly components (for example using an identical controller) could be fashioned to allow swapping a single battery between different wattage motors? Any thoughts or comments in this regard would be greatly appreciated. Thanks!

 

[indianajo]

No.
Different wattage, battery for higher wattage will serve lower wattage. (see max discharge current rating).
Different voltages, all controllers & motors are designed & wound for 1 voltage.

 

[OverflySportsmanXY]

Thanks. So for example I can use a 1000W battery on my48V 500W motor but it must be a 48V battery, you cannot use any other battery voltage other than the designated motor and controller voltage. So I guess it’s 2 batteries if I decide to build both bikes...

 

[harryS]

I have converted more than a half dozen bikes to electric, I soon realized it was in my best interest to go with a dual voltage controller, so I could use the same batteries if I wanted.

In general, if you have a 48V battery, doesn't matter what it's capacity, you can use it on a dual voltage controller with a 36V motor. The motor will just run faster at max throttle, and it's up to you to exercise restraint.

So buy your 48V kit. Later when you look at the 500W front motor, it depends on what you buy, Some of these guys, like ebikeling, are already using dual voltage controllers.

 

[OverflySportsmanXY]

Thanks for the further explanation. These are the controllers I hope to use (Model S9-61(500W/25A) and Model S6-61(350W/15A)) both of which show "Battery Voltage: 24/36/48V." Are these both then considered "tri-voltage" controllers because the 3 voltages are presented??? And if I can go with a 48V battery I assume it needs to be no greater than 15Ah to avoid overtaxing the 350W/15A current output???

 

[harryS]

There is a controller setting with the above to set the voltage. Then the controller knows what low voltage cutoff to use.

The 15AH tells you how much capacity is in the battery. You could go higher, and pay more money, if you want range. You go less, and you get less range.

The first controller can request up to 25A, so you need a battery that can supply at least 25A,

 

[HoopersEbike]

See if the 36v controller can handle 48v a lot can handle more than the advertised voltage, I just got done adding battery quick disconnects to my bike and it works great if you put disconnects on both and the controller can handle it you would be able to switch the battery between both

 

[OverflySportsmanXY]

Yes that’s exactly what I’d like to do get a battery pack and a second battery cradle/holder then just swap a solid single 48V battery instead of purchasing multiple “mediocre” ones... I think it might work with a 48V 15Ah battery maybe I’ll increase the Amp hours if I can find a good value...

 

[HoopersEbike]

Yes that’s exactly what I’d like to do get a battery pack and a second battery cradle/holder then just swap a solid single 48V battery instead of purchasing multiple “mediocre” ones... I think it might work with a 48V 15Ah battery maybe I’ll increase the Amp hours if I can find a good value...

15 ah supplying a 350 or 500w motor should give you a good amount of ride time especially if you are using peddle assist

 

[OverflySportsmanXY]

I think 15Ah is the sweet spot as well...thanks for the help!!!

 

[indianajo]

Thanks. So for example I can use a 1000W battery on my48V 500W motor but it must be a 48V battery, you cannot use any other battery voltage other than the designated motor and controller voltage. So I guess it’s 2 batteries if I decide to build both bikes...

I think you are confusing the watthour rating of batteries (like gallons of gas in tank) with the wattage rating of motors (like horsepower). Different things. Watt rating of battery is not published, but some of them have a maximum current rating. Plus the wattage rating of motor is how much electricity it will consume, not how many lbft of work done on the ground by the tire per hour. My "1300 watt" rated geared hub motor measured 6 mph max on 15% grade at 330 lb gross, or about 340 watts.

 

[kochcik]

I have converted more than a half dozen bikes to electric, I soon realized it was in my best interest to go with a dual voltage controller, so I could use the same batteries if I wanted.

In general, if you have a 48V battery, doesn't matter what it's capacity, you can use it on a dual voltage controller with a 36V motor. The motor will just run faster at max throttle, and it's up to you to exercise restraint.

So buy your 48V kit. Later when you look at the 500W front motor, it depends on what you buy, Some of these guys, like ebikeling, are already using dual voltage controllers.

Hi, I am building my first ebike now. And no I faceing pretty similar problem. So far I mounted 48v rear hub1000w motor from ciclotricity (UK). This comes in resticted road-legal mode - 250w (you can decode it and have 1000w off road mode). I tested it and it cames out too short range and underpowered for me. So I got second 48v battery for extanding the range but also I want 250w front hub kit. But the motor is 36v. Just to go by this voltage defference I thought I'll buy simmilar controler and LCD board from the rear a aleready have. I hope that with restriction to 250w on 48v controler I could run 36v motor with no worries. Does it make sense?

 

[harryS]

Wow, they did a great job on the Cyclocitry installation manual. I bet many DIY questions are covered in it!

You will have two similar Cyclocity controllers that run on 48V? Sure, they will power any ebike motor that uses the same connector wiring. The rated voltage of the motor doesn't matter.

 

[kochcik]

Yes. Two 48v controlers and LCDs and I belive all the wireing is similar. What is more I think all their LCD and controllers are the same just programmed different to different kit. Shame they stopped selling 1000w v48 front hub kits (I understand the wheel was a bit heavy) but it would suite me perfectly or at least they could use the same voltage for all their kits. There will be also two throtels unless i figure out wires to make a split and than use one for two kits... Anyway parcel comes today