Battery Options

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caseys_32
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Battery Options

Before last week i have very little knowledge of ebikes, batteries, electricity etc., but since then I have spent all my free time researching for the best/cheapest way to make a decent ebike.

I'm looking for something to use as my main form of transportation, hoping to only have to use my car when i need to go more than 15 miles away. My main stubmiling block (as it seems to be with everyone) is which battery to go with. I originally wanted a chain setup so i could have more leeway to play with things like gear ratios, but to simplify the design I decided to go with a BD-36 from Battery Space. Its one of the cheapest hubs i've seen and still 600w at 36v, plus what i've read seems good reviews. Are their better options options at a similar price (250-300)?

I've always been more of a DIYer and i've done a little bit of soldering, so for batteries I decided I wanted to build my own pack. I'm planning on 48v and 15-20ah. I was wondering if anyone had input on the following options:

A:
$380
D size Nickel Cadmium Rechargeable Battery 7000 mAh (R1ED-GD7000)
http://www.batteryjunction.com/r1ed-gd7000.html
80 batteries - 40s2p
48v, 14ah, 28 amps at 2C, $.75 per/WH
9 pounds

B:
$398
TrustFire Protected TR 18650 2500mAh 3.7V Batteries
http://www.dealextreme.com/details.dx/sku.6979
104 batteries - 13s8p
48v, 20ah, 40 amps at 2C, $.41 per/WH
21 pounds

C:
$409
Trustfire 18650 24000mAH w/built in PCB
http://www.dealextreme.com/details.dx/sku.5776
91 batteries - 13s7p
48v, 16.8ah, 33.6 amps at 2C, $.51 per WH
19.5 pounds

D:
$265
Powerizer 10000mAH D Cells
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=709
40 batteries - 40s1p
48v, 10ah, 20 amps at 2C (rated to 30amps), $.55 per WH
14 pounds

Alright, bunch of newbie questions:

1. Better cells for what i'm looking to do?
2. Do these have enough amps? Would they be able to run the BD36 efficiently?
3. Are multiple parallel strings ok? I see one guy on these forums made a pack with 500 AA 2600mah (50s10p) batteries.
4. If i was going to use either B or C of these options should i build them as parallel strings and put them in series or in series then parallel? Or does it matter?
5. I wasnt able to find a data sheet for the Trustfires, anyone know how they would handle 2C?
6. Can you solder a battery with built in PCB without damaging it?

Thanks for your time!

dogman
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Joined: Tuesday, April 29, 2008 - 15:41
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Re: Battery Options

How far do you want to go? If under 8 miles all you need is 12 ah lead acid. You may even get a 36 volt charger with the hub like I did. I like my ping, but those can't be had for awhile. Still, the whole bike cost me just under $900.

Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global

caseys_32
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Last seen: 12 years 2 months ago
Joined: Monday, June 16, 2008 - 15:23
Points: 5
Re: Battery Options

I was hoping to get about 20 miles. Farthest i will go is about 10 miles one way, and wont be able to charge before returning. Also, I'm going to have to take the bike up and down a flight of stairs everytime i use it so i was hoping to go with something lighter than SLA, LifePO4 would be ideal but the timing seems poor right now. I would like max speed to be around 30mhp, and average about 20mph for my 20 mile trip. I see based on another forum post 36v SLA with the BD36 is about 25mph and 48v is about 32mph, but Range as mention is only 6-8 miles. Any suggestions for that range/speed?

dogman
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Last seen: 10 years 10 months ago
Joined: Tuesday, April 29, 2008 - 15:41
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Re: Battery Options

What you will need is 48 volt 20 ah lifpo4 to do that without a recharge, and maybe a touch less speed. My BD36 at 36v bike goes 18 miles full throttle, but that includes a really big steep hill. I suspect it would go 20 miles on easier terrain. Ping may be able to help you, email him to find out. I just heard he solved his shipping problems. I can't imagine he was happy with no money for several months. Back to the range issue, go ahead and get the 48 volt, but do realize that if you really go full throttle all the way you will be really trusting the bms to save your battery every cycle. Much better for you to ride around 25 mph, which is as fast as most bikes are geared for unless for racing, and save a little margin in the battery. Too expensive to do a destruction test every ride . Better still to solve the charge problem. 8 hours of charging costs less than a dime. Tell your boss to get green.

Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global

caseys_32
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Last seen: 12 years 2 months ago
Joined: Monday, June 16, 2008 - 15:23
Points: 5
Re: Battery Options

Thanks for the info, i shot ping an email, will see what I get back.

caseys_32
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Last seen: 12 years 2 months ago
Joined: Monday, June 16, 2008 - 15:23
Points: 5
Re: Battery Options

Been a week an no word from Ping assume that means he is either very backlogged or not selling packs right now? Plan B, do you think the trustfires would work? Is there another trusted low cost seller?

dogman
dogman's picture
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Last seen: 10 years 10 months ago
Joined: Tuesday, April 29, 2008 - 15:41
Points: 830
Re: Battery Options

Sorry, unfortunately I was mistaken, the guy posting about getting a ping shipped had ordered last month. I was too quick to put out the word. So, so far no return to buisness for him yet. There are some good looking fox batteries on ebay now, that should be more durable than the ping, but of course not as inexpensive. supposedly they can deliver more amps than a ping so maybe you can afford a smaller one of those.

Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global

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