Ideal Battery Size For a 48V 1000W E-Bike (Solved)

RonnieBrowen2106

RonnieBrowen2106

100 W
Joined
Apr 10, 2017
Messages
276
Location
Duluth, MN
Hi I am building a new electric bike. The last one I built was a 36V 500W bike and I used a 36V 14Ah Li-ion battery = 506 Watt hour of power. The controller could output 22 +/- 1 A so that is at the least 756W output. I am thinking of getting a 48V 15Ah battery, which is 720 Watt hour power. But I will have 2 once the old bike sells. The 36V battery was $356 USD and the 48V 15Ah is $331 USD, but it is Lifepo4. And it is mounted on the inside of the bike frame. That is much better than the rack mounted one on my current bike. That makes the bike better balanced. So what are your thoughts?
 
I used 900Wh Samsung 25R battery. It got me 20+ miles riding 30-35 although I am lightweight and ride in an aggressive position. The ideal battery size depends on a few things and it could be pretty big, like 2 or 3 Kwh if you ride fast and want to cover a lot of distance between charges.
 
Ideal? Biggest and best you can afford.
 
The ideal battery is the battery best suited for the application and needs of the user.
What is the ideal haircut, or what is the ideal bike?

The ideal battery for my cargobike is a large battery (4kwh+) that can go for many days of regular commuting without charging.
It would be even better if it was built of the best cell tech, as that would give even more range or lower weight.
The reasonable compromise I went for was decent energy density 18650s for a cheap price.
This battery is hardly ideal for most bikes as it simply is too heavy and clumsy.
 
Small batteries cost less, weigh less, and are easier to fit onto a frame....a larger battery puts less stress on each cell, and will last longer. If this is your first ebike, get the smaller battery and beat the crap out of it...while you study more, and save up money for your second ebike.
 
Mods don't read? :D

To add more light to the situation, if not pedaling you might use 25 watt hrs / mile on the low end and 40 watt hrs / mile on the high end. Figure out the distance you want to go between charges and size the battery based on that.
 
Thanks flat tire. That is very useful. I plan on going about 12 to 15 miles round trip to and from work. Duluth is about 20 miles long by 5 miles wide. It is not a super huge place. I want a range of 20 miles.
 
Go for 800Wh+ and you can basically ride it as you please for those 20 miles assuming no hills.
 
RonnieBrowen2106 said:
Thanks flat tire. That is very useful. I plan on going about 12 to 15 miles round trip to and from work. Duluth is about 20 miles long by 5 miles wide. It is not a super huge place. I want a range of 20 miles.
Click to expand...

Duluth is cold. I'm in the SE corner of the state, and I have to say many cool days I'm happy I have a 20Ah battery and the extra power when the cold robs some of the oomph. 14.5 will be fine but that extra sure is nice when it's a chilly day. We had a lot of rideable winter days this year.
 
You know, I find it odd that my LiPo's @ 20Ah got me 25km. I go to Jusints Trip Simulator Beta and find out I shoulda gotten more distance, like double. The last few days I have been having troubles running out of juice on my rides. I think its a matter of voltage sag depleting Ah faster. But again based on the Trip Sim, I should be getting more distance.

Having a pack at 48V and 15Ah is decent to not have trip anxiety.
 
markz said:
You know, I find it odd that my LiPo's @ 20Ah got me 25km. I go to Jusints Trip Simulator Beta and find out I shoulda gotten more distance, like double. The last few days I have been having troubles running out of juice on my rides. I think its a matter of voltage sag depleting Ah faster. But again based on the Trip Sim, I should be getting more distance.

Having a pack at 48V and 15Ah is decent to not have trip anxiety.
Click to expand...
I have managed to go 11 Miles so far, and my battery is at half power now.
 
11 miles seems decent to me and for the entire pack 20 miles, which is 32km which is more then enough for me.
I am going to double up my pack, to reduce voltage sag, go from 6Ah 41Vmax (36Vnom) to 12Ah and baby the motherfucker.

I love the idea of guerilla charging, I did my first one a few days ago at a gas station. I find it cool to pump in huge amounts of juice from a normal wall outlet and do it at a rate of 1C or 2C.

When you have a big enough pack, no need to guerilla charge. Just do your thing, come home, charge to 3/4 and leave it be for a day or 2, then when ready to ride, juice it up if you need to go far, if not ride as is.
 
markz said:
11 miles seems decent to me and for the entire pack 20 miles, which is 32km which is more then enough for me.
I am going to double up my pack, to reduce voltage sag, go from 6Ah 41Vmax (36Vnom) to 12Ah and baby the motherfucker.

I love the idea of guerilla charging, I did my first one a few days ago at a gas station. I find it cool to pump in huge amounts of juice from a normal wall outlet and do it at a rate of 1C or 2C.

When you have a big enough pack, no need to guerilla charge. Just do your thing, come home, charge to 3/4 and leave it be for a day or 2, then when ready to ride, juice it up if you need to go far, if not ride as is.
Click to expand...
I think my bike will go 22-25 miles per charge. it was not fully charged before my testing. It was probably close. I don't have a charger for it because the one that came with the battery was a dud. The seller is sending me a new one though.
 
There's no 1 ideal battery. That's like asking for an ideal gun.

Close-range:shotgun VS long-range:rifle.

Are you going for all out blistering acceleration or range or both? There's also the "good, fast, cheap" triad that you also need to contend with. You only get to choose 2 from the Triad. Some person's ideal battery is 'low cost', yours may be 'high quality', another may want it immediately.

As far as size is solely concerned, I would get the largest battery that you can 1) afford, 2) tolerate the weight of, 3) care for properly. Larger batteries have advantages in range, longevity (calendar- and cycle-life; due to less extreme cycles), and cost/ Wh
 
cal3thousand said:
There's no 1 ideal battery. That's like asking for an ideal gun.

Close-range:shotgun VS long-range:rifle.

Are you going for all out blistering acceleration or range or both? There's also the "good, fast, cheap" triad that you also need to contend with. You only get to choose 2 from the Triad. Some person's ideal battery is 'low cost', yours may be 'high quality', another may want it immediately.

As far as size is solely concerned, I would get the largest battery that you can 1) afford, 2) tolerate the weight of, 3) care for properly. Larger batteries have advantages in range, longevity (calendar- and cycle-life; due to less extreme cycles), and cost/ Wh
Click to expand...
I have already found what I need. The 48V 15Ah Lifep04 battery is perfect for my needs.
 
markz said:
What you gunna buy and where?
Click to expand...
I have already bought the battery. I have already been test driving the new bike. The bike itself is still unfinished due to lack of spare funding and waiting on replacement charger and other parts to be delivered.
 
I been riding a lot myself, dodging rain clouds, no stares......yet but that kit I bought is pretty tame. I like my MXUS 3kw better then the Conhismotor kit.
 
markz said:
I been riding a lot myself, dodging rain clouds, no stares......yet but that kit I bought is pretty tame. I like my MXUS 3kw better then the Conhismotor kit.
Click to expand...
I wish 3kw kits were legal in MN. They would be lots of fun...... :( I have all the parts but the charger and battery bag. Soon my Frankenstein project will be finished. The bike shop said that parts are not very interchangeable, but every part I have bought and installed works flawlessly. Sometimes better than the original parts that were on the bike.
 
3kw is not legal anywhere except private property.

Do not be concerned at all about the power rating, just ride with respect and common sense.

I tell you this, I am by no means a speed demon, the fastest I have gotten in the week or so of ebiking is 35kph. My goal for 3kw direct drive is to lace it into a smaller diameter wheel 22", a 36h moto rim which I have and to top my speed out at a certain #, say 40kph, but have the sweet spot in my cruise range of 25kph or perhaps a little slower, I havent decided yet. I want a hill climbing beast.

To tell you the truth, I have been eye balling some steep hills for the longest time. And I wonder to self, Self wouldnt it be nice to power on up that frocking steep ass hill. Lemme find some snap shots for you. frock that, google maps will work. I will do a street view for you.

https://www.google.ca/maps/@51.0632305,-114.1485183,3a,15y,251.38h,91.31t/data=!3m7!1e1!3m5!1scqpzwl8pgDo9tctT7ioaow!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3Dcqpzwl8pgDo9tctT7ioaow%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D29.290852%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

https://www.google.ca/maps/@50.8947401,-114.0046286,3a,20.3y,104.38h,88.03t/data=!3m7!1e1!3m5!1sgUGsMC00ZSzr7laAUf85uA!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3DgUGsMC00ZSzr7laAUf85uA%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D306.69962%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

Those are the dreams!
 
markz said:
3kw is not legal anywhere except private property.

Do not be concerned at all about the power rating, just ride with respect and common sense.

I tell you this, I am by no means a speed demon, the fastest I have gotten in the week or so of ebiking is 35kph. My goal for 3kw direct drive is to lace it into a smaller diameter wheel 22", a 36h moto rim which I have and to top my speed out at a certain #, say 40kph, but have the sweet spot in my cruise range of 25kph or perhaps a little slower, I havent decided yet. I want a hill climbing beast.

To tell you the truth, I have been eye balling some steep hills for the longest time. And I wonder to self, Self wouldnt it be nice to power on up that frocking steep ass hill. Lemme find some snap shots for you. frock that, google maps will work. I will do a street view for you.

https://www.google.ca/maps/@51.0632305,-114.1485183,3a,15y,251.38h,91.31t/data=!3m7!1e1!3m5!1scqpzwl8pgDo9tctT7ioaow!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3Dcqpzwl8pgDo9tctT7ioaow%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D29.290852%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

https://www.google.ca/maps/@50.8947401,-114.0046286,3a,20.3y,104.38h,88.03t/data=!3m7!1e1!3m5!1sgUGsMC00ZSzr7laAUf85uA!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3DgUGsMC00ZSzr7laAUf85uA%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D306.69962%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

Those are the dreams!
Click to expand...
What about geared hub motors? Maybe try one or two of those on your bike.
 
Yup got me a BMC V1 for $20 that needed gears and a cover. Bought the gears and procrastinated on the cover, which I bought from em3ev. Now I need to tap 3 holes for the cover, or just use existing 3 holes instead of 6.

It should be fun, no drag, a little more noise which means more heads turning as I pass.

EM3EV's MAC motor is a good choice for geared hubs, which I woulda bought if I didnt find this BMC. Plan to use my sunwin controller with it, its already laced into a 24" wheel, with hookworm tires. Pretty sweet of a deal I got on it.
 
I want more torque from my bikes. Once I sell my old bike I will build a new one with geared motors. The foster home I live at said I can only have two bikes. So I will hopefully finish the other bike before the other sells. Electric bikes have turned into a rather fun hobby.
 
Well I read these BMC's you can go high wattages. I think its rated at 350 or 500W, but I will do 750W and see.
I cam to the conclusion that instead of fabricating a homemade freewheel from a rear wheel hub, I will turn it into a front motor. Now the flats maybe too wide, I havent eye balled it yet, but it will be easy for me to cut the axle to extend the flats inward.

I am getting tired of the drag direct drive motors cause. So I will use DD on a bike where I intend to do little pedaling carrying lots of batteries and just cruising around, and the geared motor on a light setup (A to B setup).

The only other geared motor I tried was a wimpy ass geared BRUSHED motor that came from Canadian Tire, 250W and I burnt the brushes on that in short order.

I like tons of torque but speeds no more then 40kph, cruise at 25-30kph, thats where I want my high efficiency range.
 
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