Custom Built Li-ion Battery Pack

[LouisvilleScanMan]

Ok I was looking around on ebay and saw these

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

That gave me the idea to make a large battery pack out of them.

With 48 3.7v 5000mah aa cells, put them 4 in series for 14.8v, 48 divided by 4 = 12, then connect the 12 14.8/5ah batteries in parallel to get 60ah @14.8v.

Result: a 14.8v 60ah li-ion battery that weighs a little over 2lbs

2 questions, can this even be done and how would I charge this battery pack?

 

[Nap]

Don't even think about it. You'll need some elaborate circuit to monitor each cell's voltage and temperature and balance both charge and discharge. Also e-bay is not the most reputable source for Li-Ion cells . You can read here about what can happen with something as simple as 2 e-bay Li-Ion cells in series in a flashlight:

Smoke and Fire, Hot Cells and Close Calls - The dangerous side of batteries

 

[Essexscan]

Hi Nap!, Fellow member on CPF?

5000Mah seems a little high for a legit 18650 cell that and they are a little on the too cheap for your own safety side so quality control probably went out the window. I would not make any kind of battery pack out of them and definitely wouldn't charge them even one at a time in my house unless i was looking to burn it down. Li-ion batteries are not toys they store too much energy and can burn like a flare not to respect them and pay for quality cells

 

[Nap]

Hi Nap!, Fellow member on CPF?

Yes, LOL! Nice to meet you here too!

You guys are bad

 

[Thayne]

The day is coming for a hobbyist to try something using Li-ion bats; too bad they are so expensive. I think I read the Tesla (Auto) uses some basically adapted from laptop batteries. I never looked in detail at hybrid cars, but I bet some guys will come up with some ingenious ideas to run radios, etc.

I have a portable emergency pack with 3 mobiles & 2 10AH gel cells in it; it works great to put in different buildings or vehicles, but is a b****h to carry it very far into the woods :lol:

 

[LouisvilleScanMan]

The day is coming for a hobbyist to try something using Li-ion bats; too bad they are so expensive. I think I read the Tesla (Auto) uses some basically adapted from laptop batteries. I never looked in detail at hybrid cars, but I bet some guys will come up with some ingenious ideas to run radios, etc.

I have a portable emergency pack with 3 mobiles & 2 10AH gel cells in it; it works great to put in different buildings or vehicles, but is a b****h to carry it very far into the woods :lol:

That was my reason for looking into Li-Ion, 60ah for 2.2lbs sounded too good to be true. I have a craftsman toolbox with a UB12350 35ah and it weighs about 30lbs.

 

[mancow]

Thales uses the 18650 cell for their T25 batteries. But, there is a board in there the size of a Transcrypt freq hopping module just to feed and care for them.

 

[K9WG]

Don't even think about it. You'll need some elaborate circuit to monitor each cell's voltage and temperature and balance both charge and discharge. Also e-bay is not the most reputable source for Li-Ion cells . You can read here about what can happen with something as simple as 2 e-bay Li-Ion cells in series in a flashlight:

Smoke and Fire, Hot Cells and Close Calls - The dangerous side of batteries

Nap is correct, you do not want to mess with Li-Ion unless you know what you are doing. Li-Ion has brought down aircraft. I don't even leave my laptop, camera, etc. on charge when I am not around.

 

[LouisvilleScanMan]

Li-Ion has brought down aircraft.

When did that happen?

 

[AK9R]

News articles about a UPS cargo plane crash that was attributed to lithium batteries:

Report faults batteries for UPS plane crash - Washington Times

Report on UPS Jet's Crash Highlights Batteries - WSJ.com

Lithium Battery Fire Risk Probed In Dubai Crash | AVIATION WEEK

Wikipedia article:

UPS Airlines Flight 6 - Wikipedia, the free encyclopedia

FAA Safety Alert regarding transporting lithium batteries as cargo:

http://www.faa.gov/other_visit/avia...afety/safo/all_safos/media/2010/SAFO10017.pdf

DOT restriction on packing lithium batteries in checked baggage:

Safe Travel

Web page about lithium battery failures:

Lithium Battery Failures

 

[Thayne]

That was my reason for looking into Li-Ion, 60ah for 2.2lbs sounded too good to be true. I have a craftsman toolbox with a UB12350 35ah and it weighs about 30lbs.

Thats Funny--Mine is a craftsman toolbox too--and it still looks like one except for a few BNC's & 1 N connector sticking out the back :lol: If the lid is closed it looks completely normal unless you get close enough to see the 2" holes that match up with the 2 Kenwood TK-780-880 radios inside.

 

[SCPD]

I would check Airsoft Websites. You can get 11.1v Lipo's or 14.8v Lipos for cheap. They'll have an output rating on them in "XXC" where X is a number.

Then you can solder on a connect to each one and rotate through them if you wish to use multiple batteries.

Also a lot of the sites sell Tenergy Lipo chargers for about $30. I've not had any issue with mine, given that I've only charged one at a time!

I put a lot of thought into these ideas too, so I'll have to repost sometime when I play around with them more.

 

[LouisvilleScanMan]

Thats Funny--Mine is a craftsman toolbox too--and it still looks like one except for a few BNC's & 1 N connector sticking out the back :lol: If the lid is closed it looks completely normal unless you get close enough to see the 2" holes that match up with the 2 Kenwood TK-780-880 radios inside.

Pretty much describes mine. Welcome to Facebook - Log In, Sign Up or Learn More

 

[prcguy]

There is a new breed of Li-Ion cells developed for the electric car (full size) industry made by A123 Systems and the most common cell is known as the ANR26650.

Its 3.3v @ 2.5AH with Lithium Nanohosphate chemistry and its maximum current discharge rate is 70A. That's not its momentary discharge rate, that's its every day continuous rate until its discharged.

You can parallel these forever to make a monster 12v pack and they are very safe to charge and are very immune to abuse, unlike the older laptop style Li-Ion cells that are known in the R/C airplane hobby to burn down houses when charged unattended.

I have a pack made with two parallel groups of four cells in series and it powers a 100W radio just fine with constant keydown in CW with virtually no voltage drop. I use it to power portable HF rigs on travel or while camping.

Many companies make the packs for ham radio use and Buddipole is a good source for premade packs and chargers.
prcguy

 

[Thayne]

There is a new breed of Li-Ion cells developed for the electric car (full size) industry made by A123 Systems and the most common cell is known as the ANR26650.

Its 3.3v @ 2.5AH with Lithium Nanohosphate chemistry and its maximum current discharge rate is 70A. That's not its momentary discharge rate, that's its every day continuous rate until its discharged.

You can parallel these forever to make a monster 12v pack and they are very safe to charge and are very immune to abuse, unlike the older laptop style Li-Ion cells that are known in the R/C airplane hobby to burn down houses when charged unattended.

I have a pack made with two parallel groups of four cells in series and it powers a 100W radio just fine with constant keydown in CW with virtually no voltage drop. I use it to power portable HF rigs on travel or while camping.

Many companies make the packs for ham radio use and Buddipole is a good source for premade packs and chargers.
prcguy

Good Info, I will look into it--Thanks.