Battery pack for Osram 400W 36V

[troller_cpf]

Hi guys,
I'm going to build/mod an old spotlight with the Osram HLX64663 36V 400W halogen bulb, and I've got to build the battery pack, as the standard SLA battery cannot be used for obvious reasons.

My idea is to put 10 Li-Ion 18650 (3000mAh) in series so to obtain a nominal voltage of 37V and 3000mAh.
In this configuration I should get 16 minutes of light (on paper).

Question is: the Osram lamp, being a 36V, should require 400/36= 11 Amps, and m battery pack is only delivering 3 Ah.

Is it ok anyway? I mean, will the bulb light up at full power? I have a doubt about this but then I look at the Mag623 wich has a 12V 100W bulb = 8 Amps required to the bulb and the classic battery pack used is just 1.4 Ah, and it works perfectly.

Following that "math logic" in the Mag623 the battery pack has an equivalent of 0.175 times the amp to the bulb, and in what I'd do my battery pack would have an equivalent of 0.27 times the amp to the bulb, so it should work fine by logic.

any comments?

thanks everybody!

 

[Jarski]

I doubt that 18650 3000mAh li-ions will be able to deliver 11 amps. I think that Mag623 has IMR cells in its battery pack, and they deliver much more amps than "regular" li-ions. Correct me if I am wrong!

 

[The Dane]

It has been done before directly with DeWalt 36V LiFe batteries.
I think is was a 700/300W PAR64 lamp.

http://www.candlepowerforums.com/vb/showthread.php?t=189089&highlight=1000W+PAR64

http://www.candlepowerforums.com/vb/showthread.php?t=183090&highlight=1000W+PAR64

 

[zelda]

Most high capacity 18650 Li-Ion are only rated to 2C --> 2 x 3Ah = 6A
@5A they drop very fast with the voltage.

Go on with A123 or something simular. (Li-Fe)

zelda

 

[troller_cpf]

Most high capacity 18650 Li-Ion are only rated to 2C --> 2 x 3Ah = 6A
@5A they drop very fast with the voltage.

Go on with A123 or something simular. (Li-Fe)

zelda

by saying A123 you mean rechargeable 123 (16340) OR non-rechargeable (like SF123)??

 

[Jarski]

I think that he means http://www.a123systems.com/ cells. They can keep up with +30amp draw, depending on cell.

 

[rmteo]

Use 2 of these in series and you have a compact, lightweight, 37V/5000mAH battery pack (equivalent to 20x 18650, 2500mAH cells) for about $100. Current draw up to 100A.
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8582

Capacity: 5000mAh
Voltage: 6S1P / 6 Cell / 22.2v
Discharge: 20C Constant / 30C Burst
Weight: 754g (including wire, plug & shrink wrap)
Dimensions: 145x50x48mm
Balance Plug: JST-XH
Discharge Plug: 4mm Bullet-Connector

With a hobby chager, you can balance charge these safely and get the best performance out of the pack.

 

[troller_cpf]

I was thinking about placing two of these in series:
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=9263

I should get a 37V pack, 3Ah with a constant discharge rate of 60A, which should be more than enough for the 11,1 A required from the Osram 400W, and it should last for about 16 minutes.

What do you think?
Also because I think that after 42V the lamp will

thanks!

 

[sylathnie]

I'm powering that exact bulb in the Sublimator. I've used 10 IMR cells that I harvested from two Ryobi One+ LION packs. The cells will warm slightly but haven't seemed to suffer from any ill effects. I've run them through many cycles now with no appreciable loss of capacity. I see an average current draw of about 13Amps.

Just be very very careful. That many amps at the voltage level is pretty nasty. The voltage isn't enough to "shock" you per say but it will spot weld things together (multimeter probe to flashlight body) and cause small wires to heat up quickly.

The Ah rating of a battery is it's capacity. A 7 Ah battery could in theory provide 1 Amp for 7 hours at it's nominal voltage.

The discharge rate of the battery is much more important to this equation. Discharge rates are expressed in C. a 1400 mAh cell with a 2C discharge rating can provide up to 2.8A of current safely.

It's a very bright bulb and it seems to have a nice life time at that level. It just takes some serious juice to power it. :candle:

 

[Norm]

The Ah rating of a battery is it's capacity. A 7 Ah battery could in theory provide 1 Amp for 7 hours at it's nominal voltage.

SLA batteries are rated over a 20 hour discharge not 1 hour.
Norm

 

[plasmaman]

Hi guys,
I'm going to build/mod an old spotlight with the Osram HLX64663 36V 400W halogen bulb, and I've got to build the battery pack, as the standard SLA battery cannot be used for obvious reasons.

My idea is to put 10 Li-Ion 18650 (3000mAh) in series so to obtain a nominal voltage of 37V and 3000mAh.
In this configuration I should get 16 minutes of light (on paper).

Question is: the Osram lamp, being a 36V, should require 400/36= 11 Amps, and m battery pack is only delivering 3 Ah.

Is it ok anyway? I mean, will the bulb light up at full power? I have a doubt about this but then I look at the Mag623 wich has a 12V 100W bulb = 8 Amps required to the bulb and the classic battery pack used is just 1.4 Ah, and it works perfectly.

Following that "math logic" in the Mag623 the battery pack has an equivalent of 0.175 times the amp to the bulb, and in what I'd do my battery pack would have an equivalent of 0.27 times the amp to the bulb, so it should work fine by logic.

any comments?

thanks everybody!

18650 will explode at this sort of current draw

I used the 36v 400w bulb in this

http://www.candlepowerforums.com/vb/showthread.php?t=195049&highlight=hozelock

 

[jasonck08]

Definitly do not use traditional LiCo 18650's or they will explode or vent flames at 11A current.

I'd suggested using a Lipo pack or some Lifepo4 cells like A123's or something.

Keep in mind that you will probably want to (if possible) slightly over drive the bulb... you will get a lot more lumens.

Batteries will sag quite a bit underload and will only be at there "nominal voltage" under load for a couple minutes.