Choosing ebike battery for magic pie 3

L

liamcaff

1 kW
Joined
Feb 17, 2013
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445
Location
Dublin
Hi,

So I have been reading and reading this forum and any website I can about ebike kits and batteries. I'm just about to make my first order. I am getting the Magic Pie 3 Rear kit for a 20" wheel. I will be using the internal controller for now as this is my first conversion and want to keep things relatively simple.

My dilemma is this:

My commute is either 20km each way, or a train journey and then 7 km each way. (The commute is pretty much flat except for a 2km 15degree slope on the way home.)
I will be installing the magic pie 3 on my Dahon Vitesse.

I have been given a quote for the following batteries:
16.5AH 48V battery made from 26700 cells (US$300) with 30A BMS
13.2AH 48V battery made from 26700 cells (US$260) with 30A BMS
10AH 48V battery in aluminium case made from 26700 cells (US$205) with 30A BMS
10AH 48V battery in aluminium case made from 26650 3300 mah cells (US$205) with 30A BMS

So the first question is this: if you have the choice of 26650 cells and 26700 cells, which do you choose? Is there much of a difference?
I'm having trouble figuring out if 10AH is enough for my commute, should I want to commute the full 20kms.... Should I discount the 10AH batteries and get the 16.5AH one?
The aluminium case would be nice, but the 16.5AH and 13.2AH batteries are too big (I know I can just get a battery bag).

Any thoughts would be GREATLY appreciated.

Thanks in advance!
 
For me the answer would be simple. Buy the 16 ah pack. That will give you the full 40 k range at pretty quick speed, about 35 kph.

But if you can charge at work, or will train, then the smaller ones should work if the motor is lower wattage, like below 500w.

You will need more Ah than you calculate. Cold days, windy days, etc cost you more energy. Then, you also want some extra. Extra capacity so you don't discharge to zero every day, and extra capacity so your discharge rate is lower relative to each cell. The battery will last longer if you have that headroom in both distance, and c rates.

15 ah works good for nearly all commuter ebikes, keeps the discharge rate at about 1c average even for 1000w bikes, and gives a long enough range to make the bike truly usefull. With some extra range, you can make that detour to run an errand on the way home.

One option that would work though, is train to work, ride at leisure home slower than 35 kph, with 10 ah. And again, if you can charge at work, 10 ah is also plenty. But since the pie is a pretty big motor, I'd still say the big battery is what is best. To keep that discharge rate closer to 1c. 15 ah at 1c is 15 amps.
 
dogman said:
One option that would work though, is train to work, ride at leisure home slower than 35 kph, with 10 ah. And again, if you can charge at work, 10 ah is also plenty. But since the pie is a pretty big motor, I'd still say the big battery is what is best. To keep that discharge rate closer to 1c. 15 ah at 1c is 15 amps.
Click to expand...

Thanks for the quick reply dogman! You have me leaning towards the 16.5AH battery (my own instinct too). I can charge at work, but if I end up getting the train a lot, I guess I can always buy a 10AH battery - they are much more affordable.

You raised a fundamental question for me though - when you mention discharge rate of 1c:

This is the information I received from Lin at OSN Power:
For the 16.5AH 48V Battery, the discharge rate of every single cell can reach 3C-5C. The pulse discharge rate of every single cell can reach 10C... How does this change things? Am a little confused on this.

Regards,

Liam

ps you are totally right about winds etc... I am in Dublin, Ireland and will be cycling along the coast....
 
I would take the lower c rate stated, and then cut it in half. The idea is to run your battery at a rate it finds easy, just like the rpms on a car. Say your car had a tachometer with a red line on it at 8000 rpm. It sure doesn't mean the longest engine life is running it at 8000 rpm.

But 3 c starting point instead of 2c for many other batteries does make the 10 ah size a workable deal. 10 ah at 1.5c is 15 amps, plenty to cruise 30-35 kph.

On the other hand, 10 ah makes your weekend fun riding shorter. Easy enough to solve though, by getting another 10 ah later if you really like riding long distances. 10 ah to carry will be much smaller and lighter than 16. Since you can charge at work, 10 ah is enough in terms of range for the commute, with no big detours. But that wind can half your range if it's ripping at 30 kph.
 
Thanks again for your thoughts Dogman!

So when you say "take the lower c rate stated, and then cut it in half." do you mean in general you should half whatever the manufacturer is stating as a rough rule?

So do you think 48V 10AH battery would do 22kms with enough power left over not to be completely draining the battery (as I know this is not recommended)?

I realistically can't see myself doing much more than the 22km cycle/ride to work, but I would only consider the 10AH battery if it would do 22kms comfortably.
 
You said a c rate of 3-5. So I meant take the low end, 3c, then divide that in half. 1.5c should be about what you use to cruise on flat ground most days. in 10ah, that's 15 amps, easily enough to cruise 35 kph. Turn that into time, you have 40 min of run time at 15 amps.

At 20 mph, about 32kph, you should get about 15-20 miles maximum from 10 ah of 48v. About 30 k.

So yes, under ideal conditions, the range is there, comfortably, the day the battery is new. In a year when the battery is old, range will be less, in winter, range will be less.

But there is an easy solution. Ride 25 kph, and range will increase to comfortable under less than ideal conditions.
 
You can also get two (2) 10amp/hr 48volt cases. Take one if using the train. Take two on "No" train days and weekend rides :)

Welcome to the Forum!

Tommy L sends.....
mosh.gif
 
Haha thanks Tommy! Rock on right back at ya!! (failing to find rock on smiley face!)

Am starting to lean towards the 10AH battery now! Just thinking if I upgrade to an external controller then I can change between running 2 x 10AH 48V batteries in series and parallel... for supd up short 10Ah 96V rides or long 20AH 48V rides...

Hmmmmm food for thought!


@Dogman: Thanks for the explanation. I think the 16Ah battery (as nice as it would be to have so much extra juice) is possibly too big for me for now. I will always have at least 2.5 hours to charge the battery at work, so I think the 10Ah with Aluminium case is the way to go for me for now.

I'm sure you'll be seeing a lot more of me on the forums from now on. I have been reading many of your forums up until now, but am finally making the plunge into making a custom ebike myself! Here we go!!!
 
Nice one Tommy! Loving the Lawn Tracktor Mower!!

Also loving the 128V first ride video.

Some nice guitars you got too :) I'm a recording engineer/producer/musician myself.

Back to the battery nerding :)

*\o/*
 
Anyone any thoughts on how suitable this battery back would be with the magic pie 3?

http://www.turbobikekit.com/Batteires%20LifePo4/LiFePo4-battery-pack-11.5-Ah-48V-cyclone-kit

Would you foresee any problems with the built-in controller from the magic pie 3?
 
Hi liamcaff
The 48V lifepo4 battery has a lot of power and can give you give you 50A continuous discharge and 100A max.
What is the continuous and max discharge of magic pie 3?
Does your controller restricts the power of the battery or not?
This battery has cells 38140 which are the biggest (and 40150) and can give the maximum discahrge with the big number
of charges which is >2000 times, not as the lipo :D
 
turbobikekit.com said:
Hi liamcaff
The 48V lifepo4 battery has a lot of power and can give you give you 50A continuous discharge and 100A max.
What is the continuous and max discharge of magic pie 3?
Does your controller restricts the power of the battery or not?
This battery has cells 38140 which are the biggest (and 38150) and can give the maximum discahrge with the big number
of charges which is >2000 times, not as the lipo :D
Click to expand...

Thanks for the reply!

Not really sure of the answers to your questions. I'm not sure of the the continuous and max discharge of magic pie 3. I do remember being able to select a battery for the Magic Pie 3 with a discharge for 50A - 100A on a website but can't remember which one - I'll post it here when I remember. That would leave me to believe the internal controller can handle that....

Anyone have any thoughts? I know could can always get an external controller, but for now I was hoping to avoid this.

L
 
liamcaff said:
Hi,

So I have been reading and reading this forum and any website I can about ebike kits and batteries. I'm just about to make my first order. I am getting the Magic Pie 3 Rear kit for a 20" wheel. I will be using the internal controller for now as this is my first conversion and want to keep things relatively simple.

My dilemma is this:

My commute is either 20km each way, or a train journey and then 7 km each way. (The commute is pretty much flat except for a 2km 15degree slope on the way home.)
I will be installing the magic pie 3 on my Dahon Vitesse.

I have been given a quote for the following batteries:
16.5AH 48V battery made from 26700 cells (US$300) with 30A BMS
13.2AH 48V battery made from 26700 cells (US$260) with 30A BMS
10AH 48V battery in aluminium case made from 26700 cells (US$205) with 30A BMS
10AH 48V battery in aluminium case made from 26650 3300 mah cells (US$205) with 30A BMS

So the first question is this: if you have the choice of 26650 cells and 26700 cells, which do you choose? Is there much of a difference?
I'm having trouble figuring out if 10AH is enough for my commute, should I want to commute the full 20kms.... Should I discount the 10AH batteries and get the 16.5AH one?
The aluminium case would be nice, but the 16.5AH and 13.2AH batteries are too big (I know I can just get a battery bag).

Any thoughts would be GREATLY appreciated.

Thanks in advance!
Click to expand...


Do those prices you are quoting for the different batteries include the shipping from China? If so, those are very good prices. Is OSN the seller?
 
I put my bike together this spring with the advice of some of the folks who already replied. Hope my additional info can be helpful to you.

Here's what I put together, and it's working great for my ~20km each way commute. I also charge at work so I can stay away from deep discharge, but I'm confident the battery would make it both directions on a single charge. Riding VERY hard with hills and averaging - -AVERAGING- - 32kmh, I have not exceeded 6.3kwh drain on the battery in each direction. With a 20A limit programmed, I have about 1000W of power. It's plenty, and I also pedal as I like to get a little exercise.

My hardware:
Magic Pie 3 with internal controller
Controller limited to 20A continuous via extra programming cable
Golden Motor 15Ah 48V(58V full charge) LiFePO4 battery (in a well secured backpack)
Me (~135lbs or 61kg if you prefer)

From what I can tell, the BMS on the 15Ah GoldenMotor battery is limited to 45 amps - really more than it should be, but the MP3 should never draw more than 35A.

Opinions: The battery is heavy - find the most comfortable spot for it, even if that means it's on your back. I'm a pretty skinny guy, and I don't have any problems carrying it on my back. I have found that trying to put a battery that heavy on a rear rack is just asking for trouble. No rack can support that kind of weight over bumps. Unfortunately, placing the battery in the front triangle of the bike is not possible unless you split the pack - not something you really want to do to a brand new battery.

The GoldenMotor parts are not the greatest quality. The battery seems to be solid, and I do trust it. The motor is OK, but be sure to mind the grease in the bearings. Probably worth taking apart even before your first ride and putting real grease in there. If you're not interested in the sheer speed of this motor, you may be better off buying a smaller, lighter motor that will not require such a monster battery.

Also, if you can keep the battery in a backpack, you could charge at work pretty discretely. Mine takes about 1.5 hours to recharge to full after the 20km trip.

Hope that helps. Let us know what you go with.
 
Ok i will watch the forums answers and answer after, if that ok with you
 
jimw1960 said:
liamcaff said:
Hi,

So I have been reading and reading this forum and any website I can about ebike kits and batteries. I'm just about to make my first order. I am getting the Magic Pie 3 Rear kit for a 20" wheel. I will be using the internal controller for now as this is my first conversion and want to keep things relatively simple.

My dilemma is this:

My commute is either 20km each way, or a train journey and then 7 km each way. (The commute is pretty much flat except for a 2km 15degree slope on the way home.)
I will be installing the magic pie 3 on my Dahon Vitesse.

I have been given a quote for the following batteries:
16.5AH 48V battery made from 26700 cells (US$300) with 30A BMS
13.2AH 48V battery made from 26700 cells (US$260) with 30A BMS
10AH 48V battery in aluminium case made from 26700 cells (US$205) with 30A BMS
10AH 48V battery in aluminium case made from 26650 3300 mah cells (US$205) with 30A BMS

So the first question is this: if you have the choice of 26650 cells and 26700 cells, which do you choose? Is there much of a difference?
I'm having trouble figuring out if 10AH is enough for my commute, should I want to commute the full 20kms.... Should I discount the 10AH batteries and get the 16.5AH one?
The aluminium case would be nice, but the 16.5AH and 13.2AH batteries are too big (I know I can just get a battery bag).

Any thoughts would be GREATLY appreciated.

Thanks in advance!
Click to expand...


Do those prices you are quoting for the different batteries include the shipping from China? If so, those are very good prices. Is OSN the seller?
Click to expand...

Yeah OSN is the seller. Do you have experience with them?? The prices don't include shipping from China. Shipping is bettween $70 and $90 depending on the battery weight/size....
 
sixty_cycle_hum said:
I put my bike together this spring with the advice of some of the folks who already replied. Hope my additional info can be helpful to you.

Here's what I put together, and it's working great for my ~20km each way commute. I also charge at work so I can stay away from deep discharge, but I'm confident the battery would make it both directions on a single charge. Riding VERY hard with hills and averaging - -AVERAGING- - 32kmh, I have not exceeded 6.3kwh drain on the battery in each direction. With a 20A limit programmed, I have about 1000W of power. It's plenty, and I also pedal as I like to get a little exercise.

My hardware:
Magic Pie 3 with internal controller
Controller limited to 20A continuous via extra programming cable
Golden Motor 15Ah 48V(58V full charge) LiFePO4 battery (in a well secured backpack)
Me (~135lbs or 61kg if you prefer)

From what I can tell, the BMS on the 15Ah GoldenMotor battery is limited to 45 amps - really more than it should be, but the MP3 should never draw more than 35A.

Opinions: The battery is heavy - find the most comfortable spot for it, even if that means it's on your back. I'm a pretty skinny guy, and I don't have any problems carrying it on my back. I have found that trying to put a battery that heavy on a rear rack is just asking for trouble. No rack can support that kind of weight over bumps. Unfortunately, placing the battery in the front triangle of the bike is not possible unless you split the pack - not something you really want to do to a brand new battery.

The GoldenMotor parts are not the greatest quality. The battery seems to be solid, and I do trust it. The motor is OK, but be sure to mind the grease in the bearings. Probably worth taking apart even before your first ride and putting real grease in there. If you're not interested in the sheer speed of this motor, you may be better off buying a smaller, lighter motor that will not require such a monster battery.

Also, if you can keep the battery in a backpack, you could charge at work pretty discretely. Mine takes about 1.5 hours to recharge to full after the 20km trip.

Hope that helps. Let us know what you go with.
Click to expand...

Thanks for the info - definite food for thought. I'm a pretty skinny guy too (about 10 stone). Will let ya know what I decide to do - should be ordering all the bits this week.
 
I just ordered a 48v 10Ah pack (16s, 3p) from OSN with the 26650 3.3AH cells. Just the cells, with no BMS or charger. They charged me only $136 for the cells and labor, but another $109 for shipping and paypal fee--total of $245. So, if they offered you a complete 48v 10Ah pack for only $205, I would suggest you buy it. The cells are supposedly rated at 5C continuous, and I will be putting them to the test. I have bought from OSN before. My biggest complaint with them is they do not always pack the product sufficiently and it can be damaged during shipping. Other than that, they will send what they describe.
 
jimw1960 said:
I just ordered a 48v 10Ah pack (16s, 3p) from OSN with the 26650 3.3AH cells. Just the cells, with no BMS or charger. They charged me only $136 for the cells and labor, but another $109 for shipping and paypal fee--total of $245. So, if they offered you a complete 48v 10Ah pack for only $205 shipped, I would suggest you buy it. The cells are supposedly rated at 5C continuous, and I will be putting them to the test. I have bought from OSN before. My biggest complaint with them is they do not always pack the product sufficiently and it can be damaged during shipping. Other than that, they will send what they describe.
Click to expand...


How long do they normally take to ship to you?
 
Mine was shipped last week from OSN, seven days after I placed the order. That is how long they told me it would take to build because of the backlog. I still have not received it, but the tracking number shows it was put on an airplane in Singapore yesterday. I expect it will take another week to reach my house in Texas.
 
That's not too long at all.

Thanks for the info!

jimw1960 said:
Mine was shipped last week from OSN, seven days after I placed the order. That is how long they told me it would take to build because of the backlog. I still have not received it, but the tracking number shows it was put on an airplane in Singapore yesterday. I expect it will take another week to reach my house in Texas.
Click to expand...
 
Now the status is "held by customs at destination." Let's hope it clears customs. I had an order kidnapped by customs before. They would not release it until I paid their ransom (import duty) and then the shipping company charged me an extra fee for handling the transaction, plus I had to copy and fax a bunch of paperwork. It was not pretty.
 
My OSN battery made from 26700 cells arrived yesterday. It is well made, they packaged it appropriately, and the voltages check good. I still need to install my own BMS on it before I can use it, but I will report back in a few weeks.
 
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