Im just about to strip my pit bike down and sell off the engine and exhaust on ebay to help raise funds for the Etek motor and a controller not yet chosen.
Now my main issue with this project was with batteries, the Dewalt packs seem a goot option for there ease of use and lightweight over lead acid, but im a complete newbie so dont understand what will be best for me.
Im loking at 30-45 mph and want a decent range maybe 20-30 miles if possible so i came across these cells on ebay that i think are basically the same as the ones in a dewalt pack but alot cheaper.
I have a few contacts in china that im pretty sure can get these cells for maybe $2 each so will i be able to buils up my own packs? What options would you guys suggest on batteries
Thanks
For the DeWalt packs.. you want to avoid using the built-in BMS during discharge because at the high currents you no doubt would be using in a ETEK driven bike you'll blow the BMS. It's easy enough to use the existing Dewalt pack structure, open the case of the pack and solder cables to the positive/negative terminals to the pack, bring them out, and parallel/serial connect them to form a pack. It's simple to also leave the BMS in place and you can use DeWalt's charger to charge the individual packs. You would charge one pack at a time or else have multiple chargers.
Where it starts being complicated is if you want a more convenient charging method... What I'm working on right now is how to charge them all at once. That's the Blinking DeWalt Charger thread.. I'll be posting my wiring method soon.
Um, as for the battery you mention. A Lithium-ION battery with the name 'Ultra Fire' doesn't give me any comfort as to its safety. Let me refer you back to the big story last year with exploding laptops -- due to Lithium-ION batteries catching fire. Are you sure you want a bomb on your bike? The eBay listing doesn't give any clue whether this is a safe chemistry or not, except they call it 3.7 volts which means it's not a LiFePO4 chemistry (they're rated 3.3 volts).
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Although the dewalt option might look good, you'll need a whole load of packs to get the range you want. If you wanted 20 miles and per my figuring on the other thread, lets say your bike uses 80 whrs/mile and the Dewalts have 33v nominal at 2.3 ah so 76 whrs nominal * .9 = 68.3 usable whrs. 20 miles * 80 whrs/mile = 1600 whrs in energy required so you'd need 24 Dewlat packs (68.3 * 24 = 1639.2 whrs).
I second what reikiman said about the "ultrafire lithiums". Assuming they are safe which is dumb to assume than you'd need a BMS and charger. A charger might not be too hard to find but where do you get a BMS (battery management system) and how much will that cost? A BMS is required for lithium chemistries because if the batteries are over charged or over discharged they can potentially catch fire and explode.
[url=/forum-topic/motorcycles-and-large-scooters/587-my-kz750-electric-motorcycle-project]KZ750 Motorcycle Conversion[/url]
[url=/forum-topic/motorcycles-and-large-scooters/588-fixing-my-chinese-scooter]900 watt scooter[/url]
Pic from http://www.electri
In the long term, a proper pack made of A123s (from DeWalt 36V packs) will probably suit you best, but it'll be a bit of a headache in the short term: it's fairly expensive and you'll have to build the pack yourself, wiring up the individual cells and so on.
Since you say you're a newbie, I don't think you'll want to deal with that yet. Lead-acid batteries are by far the easiest to work with, they're cheap (in the short term), safe, and they're very easy to work with since they come in high-energy sizes like 12V 50Ah or even larger. Three 12V batteries in series should be enough for the Etek, and you can get a simple 36V Soneil lead-acid charger. But if you want to keep weight down and stick with the 20Ah batteries, you might not get the range you want.
Deafscooter TOLD you i dont accpet Li-Ion Batteries
and i used happen before on high powered Scoooter
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I installed li-ion inside my World small Fx1 scooter
It already Exploded on Li-Ion like Dell Laptop Cells
then Discontined Li-ion from Deafscooter's Scooter
Here is Craig do
on Li-Ion Batteries
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Craig Uyeda
Deafscooter
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Deafscooter is Here...
deafscooter
There are many different forms of Lithium batteries.
The batteries most people recommend and talk about these days are LiFePO4 (Lithium Ferrous Phosphate - I think).
These are very different from the "Dell Laptop Cells".
Craig - I'm surprised you don't know this (you're so far ahead with everything else you do)??? So, is there some other concern you have with LiFePO4?
Thanks,
John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.
Submitted by jdh2550_1 on Wed, 09/26/2007 - 12:33. == Quote ==================
Craig -
I'm surprised you don't know this (you're so far ahead with everything else you do)???
So, is there some other concern you have with LiFePO4?
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Craig have that happen on LiFePO4 got explosive too when i uses AMPs SUCK into Monster motor
need Minuim is 1000 AMPS in PEAK Current to full power then Crusin speed about 180 amps ......
Deafscooter still use AGM with Modifed " Special doped Fluid cell make 3 times Current output "
my Kart with 1600 amps Here is ==>> http://www.austinev.org/evalbum/956
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Craig Uyeda
Deafscooter
deafscooter
What LiFePO4 cells were you using? Brand, size and maximum draw rating? 1000 Amps is a lot of current to draw! The pit bike project being discussed here could be completed with probably a 100 Amp limit and that might make LiFe's entirely acceptable...
John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.
A123 batteries are rated at 30C *sustained*. That's 70 amps for a 2.3 Ah cell! However other LiFePO4 batteries cannot handle such high discharge which is why A123s are unique. I think 10C is more normal for others?
:?
Has anyone had any long term success using the A123 batteries?
Those 18650 ultra fires look like about the same size as AA...
does anyone know if they will fit into a standard AA Battery holder.
are they called Ultrafire because they catch fire ultra quick ?
LOL
never mind the last post.. I found the measurements..
the ultra fire batteries are unprotected
here is the protected version called Trustfire which is slightly Longer.
http://www.dealextreme.com/details.dx/sku.5790