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DIY: A123 Lightweight Battery Pack

196K views 364 replies 90 participants last post by  lukemike 
#1 ·
It's not hard. Most of the hardware can be found online for less than 40 bucks. I found the cells for $5 a piece. I just ordered more cells to build another pack for my track lady. Most of this information has been generously generated by the RC hobbyist. A lot of those guys build extensive battery packs.

The A123 4 Cell pack (12 volt) was plenty for my SV650. I used a 60W Iron with a temperature control box. I soldered at 600F. My 60watt box goes up to 896F. It worked without a problem. The solder works best if you have a fat tip. They are a few bucks at the electronic store. (Fry's for me)


I already had some Gorilla glue in my tool drawer so that worked to glue the linear side of the batteries together to prevent them from moving.



# Nominal voltage: 3.3V
# Nominal capacity: 2.3Ah
# Core cell weight: 70 grams
# Internal impedance: (1kHz AC) 8 mΩ typical
# Typical fast charge current: 10A to 3.6V CCCV
# 70A continuous discharge
# 120A, 10 sec pulse discharge
# Cycle life at 10C discharge, 100% DOD: over 1,000 cycles


It only takes 5 seconds to melt the solder.

Here was my cost.

Cost $5/ea Cell
Shrink Wrap $1.50
Battery 8 gauge cables $1.50 + Terminals $1.50 (local car audio store)
Battery bars $0.99
Total: $25.50

I have a lot of shrink wrap and 2 cells left if anybody wants to buy them. $11+shipping (let me know)









8 cell pack (Jacked from R1 forum)


The battery bars can be made by anybody. This is just an example of Hyperion making battery bars. I found a pack of ten the other day for a $1.

DEANS - IDK maybe thats the name of the guy that made the bars.




Videos:





It's really fucking easy.

"When in doubt just google it." :D

Update:
Note there are a few cock blockers on the thread. I already know that you know this is a home made battery pack. I dont need to warn you that you need the right tools to accomplish this small task. Obviously anything we do at home we are responsible for our own liabilities.

I just bought a set of A123 batteries for $4 bucks a piece on ebay. So if you look diligently you will find deals. The small roach clips I got them at an electronic store for $3 bucks a pack.

Charger: Venom they are about 40-60 on ebay. The refurbished charger is okay.

 
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#148 ·
#149 ·
SO are these capable of being charged properly by the bike's charging system?
 
#156 ·
From memory the absolute maximum voltage these cells are happy to be charged at long term is 3.9. Works out at 17.6v. Well above what a healthy stator puts out. They're also quite tolerant to overcharging (i.e. they don't have the tendency of exploding that the older li-ion cells had). The general rule of thumb is don't cover the battery vent (little hole on one end - can't remeber each) and they should be fine. Not balance charging may shorten the lifespan of the cells but whatever; they're still gonna out live the pb battery in other bikes.
 
#158 ·
Bringing this back up to life - I noticed that there were 2 types of A123:
- A123 18650 cell which is made from 2008 3.3V 1100mah per cell
- A123 26650 cell which is made from 2009 3.3v 2300mah per cell

You stated that you used the 3.3V 2.3Ah cell, so I'm guessing you got the 26650 one.
Just wanted to make sure people didn't get the wrong stuff.
 
#159 ·
Its also worth noting that the 1100mah cells are about the size of a tall AA battery, and the 2300mah are about the size of a tall C or D battery. Like one and a half of those. (aproximatly)

I have an 8 cell 1100mah in my zx1100 and its not much bigger then the 4 cell 2300mah in my 454.
 
#162 ·
I can get a complete 8-cell 1100mah shipped from somewhere in asia for like $30 all soldered with cables. I may just go that route, since an 8-cell 2300mah runs $90.

Maybe I should check and see if a 6-cell 2300mah would work.
 
#163 ·
a 6 cell wont work, because an 8 cell is essentially two 4 cell packs wired in parallel to get the voltage right.

I tried putting these types of batteries in older bikes, and they go dead. Older bikes do not have the charging amperage needed to charge them.
 
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#164 ·
I realized that after reading a bit more in depth how the pack were created - it's either 4cell or 8cell to get the right voltage with just highe amperage.
The 6-cell is just a 6x3.3v 2300mah battery pack
 
#166 ·
the 1100 mah, are 40 grams in weight, where the 2300 mah ones are 70 grams in weight.that beeing said and knowing that the 1100 mah ones are much cheaper than the 2300 mah ones (less than half the price), the overall weight of an 8 1100 cell mah battery will only be 80-90 grams higher than an 4 2300 mah cell battery.
 
#170 ·
I'd like one of these for my 636 but I'm debating on 4 or 8 cell though. I like the bolt together holders so you could just buy the batteries when they go kaput & put it back together!
 
#171 ·
What the hell?
 
#173 ·
I was under the assumption that you could only use the 2300mah ones. Mainly because of the output. Is the output in these equivalent to the 23's. Also what is the life of the battery..? does it fall under the, "as long as you ride your bike it will last" category? And do they still have to be the green cell's. I'm a little lost here.
 
#174 ·
Is there many places making these batteries? I was looking online because I could probably stand to get a new battery but the ones I was seeing where like $200-$400. I'm not a professional racer so I can deal with the extra weight of a regular battery. LOL But if I can find one like this for cheaper or the same price as a stock replacement I'd be all over it.

Thanks!

p.s. I don't want to try making one myself.
 
#181 ·
look at the price of the basic components. lots of battery prices have gone up recently, as have many basic chemical prices, due to disposal and maintenance of the metals and chemicals, and the costs associated with it.

Recycle more = price goes down. (False statement... recycle more and cost goes down... price stays same because some asshole needed a 4 billion dollar a year pay raise.)
 
#182 ·
look at the price of the basic components. lots of battery prices have gone up recently, as have many basic chemical prices, due to disposal and maintenance of the metals and chemicals, and the costs associated with it.

Recycle more = price goes down. (False statement... recycle more and cost goes down... price stays same because some asshole needed a 4 billion dollar a year pay raise.)
I have to agree with you there. Fuck the man who lives so good that it depresses the poor. Also the people who send our money over seas to help there homeless while scorning and spitting on our own.

P.S. any answers on my question?
 
#186 ·
I just made an offer with this guy for 20 bucks. I am rebuilding my crashed track bike, so I am building a 4 cell for my 07 R6. Ive used the 4 cell pack on this bike before on the track and street. I havent had any problems with the warm temps in SOCAL. It may be different for people that live in colder environments. So you might need more cells.

It's a good enough weight saving to stay away from the heavy lead acid battery.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230571093280&ssPageName=STRK:MEBOFFX:IT
 
#187 ·
first off, LMFAO


second i priced a battery for my RC51 build.

the THUD of me hitting the floor was luckily loud enough for my friend to hear and come pick my ass up. 325 bucks? sorry man but thats crazy.
 
#189 ·
How many people have done this? If there are enough, can we start to compile a list of how many cells, what configuration, who did the work, exact bike, use of bike, location of bike, etc.? Maybe pics of location setup is installed?

I think it would be good to get an idea of how these work depending on the use. I read all 19 pages and haven't really hit any concrete evidence of what setup I would need to run for X bike and/or Y location.

Just a thought. And thank you to all who have contributed to this thread. It has been very informative.
 
#190 ·
Ok, here is my scenario, I have a 78 triumph 750, it is a kickstart bike. Would a 4 cell be enough to run my shit? I think it should seeing there is not going to be any kind of draw like a bike with a starter.
 
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