Make your own A123 Battery Pack

[Happy_Hamer]

So I seen on SEVERAL RC Car forums you can make your own battery packs.

I want to make one for field use with my QRP radio.

First, here is the battery I will use, 16 of them

Nominal voltage: 3.3V

Nominal capacity: 2.5Ah



This is how I ASSume it is wired. Let me know what you guys think??????

 

[W5LZ]

And will have 13.2v and 10ah. I'm not familiar with them, what kind of battery are they?
- 'Doc

 

[AudioShockwav]

They build Nanophosphate lithium ion batteries, this is like the latest tech in rechargeable battery's, I think they are using them in some of the new electric cars .

73
Jeff

 

[Happy_Hamer]

So does the wiring look correct?

Here is where I see one similar for sale

4S4P A123 Battery Pack

 

[AudioShockwav]

Looks right to me, how much each are they asking for these?
FT 817 Power pack?

73
Jeff

 

[Happy_Hamer]

They are about $135 on eBay for 16 of them.

I am searching the web for a better price

a123 26650 | eBay

 

[AudioShockwav]

I just went and looked at the Pack, only thing diff is they add a internal self-resetting polyswitch (to prevent short-circuits) and installed Anderson Powerpole connectors.
$285.00 for there product.......Just find the polyswitch and that is a big savings.

73
Jeff

 

[Happy_Hamer]

Mouser has PolySwitches, I have no experience with those and have not figured out where in the circuit it would be installed and what size I need??????

 

[AudioShockwav]

In the + lead I would think, and choose one that is rated for say 15 volts.
How much current do you need....How much does the FT 817 draw?

The Polyswitch is placed in series with the Load

Raychem Circuit Protection’s PolySwitch™ Polymeric
Positive Temperature Coefficient (PPTC) devices are
used to help protect against harmful overcurrent
surges and overtemperature faults.
Like traditional fuses, these devices limit the flow of
dangerously high current during fault conditions.
The PolySwitch device, however, resets after the fault

73
Jeff

 

[AudioShockwav]

http://www.ttiinc.com/docs/IO/6867/raychem.pdf

73
Jeff

 

[AudioShockwav]

The TE AGRF1000 Operates at 16 volts The maximum voltage across the PolySwitch device under a typical fault condition. In many circuits, this is the voltage of the power source in the circuit. It may be possible to use a PolySwitch device at a higher voltage, but each such use must be individually qualified. The largest steady state current that, under specified ambient conditions ( ie room temp), can be passed through the PolySwitch device without causing the device to trip is 10 Amp.
These are typically used in automotive apps.
Product Highlights:Radial Application
Vmax Operating = 16 V
Family Name = AGRF
Radial Construction,
Through Hole Construction
IH (Room Temperature) = 10 A
Raychem
73
Jeff

 

[W5LZ]

Oh ho, a 'li-po' battery. The R/C flyers have had them for some time, they weigh less than other types. I remember that they were not that 'simple' to use because of the charging etc, and they just aren't that cheap. I didn't/don't have to worry about weight with the R/C'ing I do so never researched them much.
Those 'Polyswitches' are neat sounding 'doo-gees'! I can see where they could really come in handy.
- 'Doc

(Be careful with those 'li-po' batteries, they do not like water at all. They are sealed not to keep stuff in, but to keep stuff out.)

 

[Happy_Hamer]

R/C Calculations

 

[Happy_Hamer]

DIY: A123 Lightweight Battery Pack - Custom Fighters - Custom Streetfighter Motorcycle Forum

 

[Happy_Hamer]

Disassembly of a DeWalt 36v Battery - RC Groups