48V 2400W EV Bike

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streethot
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48V 2400W EV Bike

Hi there, my very first post on this Forum........lots of info here...........

I am from Brazil and here we need to be very creative to do everything in order to work properly, remeber I dont have where to buy things ok, import from usa is too expensive, so we work with we have.....

So, I develop some Rc cars, converting the stinky nitro/gas powered to Eletric power.....with amazing results.......

now I am starting my first EV project......its an E-bike,

For now, I have Wheel/Tires, Front suspension, Disk brakes, and now starting assembling the frame with battery box......

For Motor: 2 x 1200W brushed motor

Battery: 4 x 12V 18A sealed

Controller: 2 x controllers for 48V x 1200W

until now its all good, but i am worried about batteries.....I would like to hear experts on this......can a Sealed batt give 50A discharge??? I know a 48x18A pack would work just fine on 1 x motor 1200W right? But 2 of them.....

Photos on the way

Thanks
Jeff

antiscab
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Re: 48V 2400W EV Bike

Hi Jeff,

specifically, what batteries are they? (brand and part number, or better yet a datasheet)

50A out of 18Ah batteries is possible on some, very bad for others.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

streethot
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Re: 48V 2400W EV Bike

i am using a sealed battery, but there is no datasheet, no specs, i didnt found the manufacturer website (?).....lets assume its a average quality Pb battery......

antiscab
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Re: 48V 2400W EV Bike

if its a gel battery,
it wont be able to do 50A, and will have a rather short service life.

If its an AGM or silicon battery, then it can do 50A continuous.
I ran 50A continuous (75A peak) on my 20Ah silicons, though i didnt do this for very long (only about 1200km before going to lithium).

For your setup, it may work, but i cant give a better answer without more information.
is there nothing at all written on the battery?

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

streethot
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Re: 48V 2400W EV Bike

In the battery only says Unipower brand and Lead Acid Sealed Battery......valvule regulated......(sorry for the english ok)

12V 18Ah

end.....lol

and I really dont know how or where to buy new batteries.....using what I have on my hands ok

streethot
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Re: 48V 2400W EV Bike

I have found a very similar batteery

http://www.electricscooterparts.com/scooterbatteries12v18ah.html

so.....datasheet says it can hold 54Amps.....for 3-5 minutes......

antiscab
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Re: 48V 2400W EV Bike

yup, that would be about right

most lead acid batteries have a rather strong peukerts effect.
capacity at high discharge rates is massively reduced.

54A for 5 minutes indicates only 4.5Ah is available at that discharge rate.
For comparison, i measured 15Ah available from the silicon (guineng) batteries that came with my emax, at the 50A discharge rate.

If you already own the batteries, and you are fine with the range they will give, go ahead and use them.
If shopping for new batteries, always compare actual capacity available at the discharge rate you are going to be using them at.
There is a significant spread between batteries at high discharge rates.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

streethot
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Re: 48V 2400W EV Bike

Yep, I already have the Batts.....where I live the next logical step would be Buy A123 (LiFePo4) Cells and assembly a new 48v20a pack.....

and talking about LiFe, someone know where to buy cells??? to assemble a good pack with low price??? I Have found chinese suppliers but not thrusted to buy........any advise would be great......

antiscab
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Re: 48V 2400W EV Bike

Id suggest A123 is overkill for your intended use.

I have personally used thundersky, and am pleased with how they have run.
their smallest size is 40Ah however.

I have also used Yesa, and am again pleased with how they run.

Headway are also rather good from what ive heard.

If you are willing to pay for a 40Ah ping battery, that would also work.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

streethot
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Re: 48V 2400W EV Bike

thanks for the reply, but the A123 cost if too much higher.....so, lipos from hobbycity are cheaper and work fine for this setup......first photos on the way!!!

aidanworthington
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Re: 48V 2400W EV Bike

hello iv messed with batteries from a young age and found that the RU batteries are best value for money un like the yusas they dont dry out and they take a lot of dischaharges ie 500plus i know my spelling ant up to mutch ( im slighly dislexic) but when it comes to electronics im most of the time lol

LIVE LONG AND PROSPER

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