looking for a pack.....

FRITZHID

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I was rummage sale'n yesterday and found a neat little grill light.
It currently uses 4s D cells and has 2 CCFL lamps. Needless to say, not the most efficient lighting available but still cool imo, soooooo I'm now looking for a 2s2p inline pack that fits in a 4D space AND is regulated down to 6v(ish) since I don't think the current internals would respond kindly to the +8v of hot cells.
Has anyone seen anything like this?
I've searched around but nothing seems to be quite right, but I may not be using the right keywords in my searches.
I'd like to avoid building the pack myself but if I must, I will.
Any exp in this area would be appreciated as well!
Ty all.

-Fritz
 

Conte

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Get Lifepo4 cells.
In my experience, a pair of lifepo4 cells will perfectly run anything designed for 6v without over driving it.
I'd probably grab a pair of 26650 lifepo4's, rig a spacer adapter and call it a day. Assuming this is a novelty light, or something you will be using as intended for grilling and can charge it between uses, you'll probably get more then enough run time without have to rig a more complicated 2s2p pack.
If you rig the adapter right, you can just swap out the 2 cells for 2 more and carry on.
That's the kind of light I would probably modular mod to take cells I have already and not make a dedicated pack for.

Sometimes those kinds of lights are not worth rigging at all. They can run sooooo long of a set of alkalines.
It's worth a try to see what kind mileage you get.

They often have very low current consumption, and you would probably just use a resistor to drop the voltage down to what you need if you're dead set on using Lico's .

Meanwhile, those lights also often have an adapter plug in that is rated for 12v so you can run then off a car. In which case, it can likely be set up to take the 8.4v. However, I'm guessing you probably would of noticed an adapter plug in by now if it had one.
 

FRITZHID

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Well, it draws almost 2A on fresh Ds so like I said, not that efficient. LED would be much much better, but I like the unique factor.
After some disassembly, the D cells are held in place with a plastic tube that's removable and will fit 6 18650 cells. 2s3p will add significant runtime. It has no external power hookup. It draws significantly more current with voltage drop (steady climbing A during use), more so then most regulated power devices I've worked with. It also has that pesky 20mA parasitic drain that I need to remedy.
I think I'm going to find another battery tube (looks like it was made from some vacuum cleaner extension or maybe one of those cheaper plastic shelving kit tubes) and build a lipo pack that just slips in. I'll charge/balance cells externally. I'll use a lm317 to tweak the voltage to where I want it. Probably just mount an additional switch on the battery lid to cut power when in standby, that way it's ready when I need it.
Based on the design, Idk if I'd want to use this on a grill.... it seems difficult to mount it in a place where it won't interfere with grilling operations or be exposed to damaging heat. I think it will become a portable utility light. It's mount is very universal so I can clamp it above a work space in a no power situation.
I looked to see if I could find more but the manufacturer only does an LED version now. The ccfl light seems brighter even tho I know lm/w are far below LED standards.
I'll see how long those thin *** ccfl tubes last, lol.
I'm just surprised no-one has a lipo "4D 6v" dropin pack. 6 18650s mah is nothing to scoff at.
 

Conte

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2 amps ? Really ?

Hmm, You may want to look on ebay for one of those PWM regulators.

Lm317 won't work. They can't handle that kind of current and need a large heatsink to even match their rating.
I've used them to make power supplies before, they are pretty gutless.
Also, I can't quite remember, but I'm pretty sure they also won't hold their regulation. They will regulate by creating a voltage drop calibrated based on the input voltage, so as the input voltage drops, so will the output respectively. At least that is if you use a simple circuit.

You'd be better off with a 7806. Fixed 6 volt so no guess work, it will hold that voltage as the input drops, but even those, I can't seem to find one greater then 1.5a. And again need to be heatsinked as they burn up the difference in heat. In fact the losses in regulators like that would probably circumvent the gains of the lipo pack.

What kind of runtime do you want ?

You could probably pack 4x 26650 lifepo4 cells into there and get 6000+ mah for a solid 3 hours of runtime without the need for regulation and protection.
Remember that lipos are dangerous and you'd also need to pack a low voltage cut off protection in there.
 

FRITZHID

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Well.... the 7806s, like you said, are 1.5A .... the lm317s I have are 2.2A if heatsinked. I'm using 317 because it's variable, I can adjust it as needed. And yes, I'll be heatsinking it.
I thought about going simple and using diodes to drop voltage but then voltage is always lower then batt by x volts.
The main reason for using 317, is it's free.... all of the components I'm using are. If I could spend the $ on new batteries or pwm power control modules, I would, but I don't, so I'm working with what I have kicking around. Everything thus far is salvage except the light itself. ($3)
I'd love to have a nice, buck/boost 6v 3A converter in this, but don't have any in my collection of parts and I'm pretty sure I can't spend the $ on one lol
 

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Oh well that changes everything. When you started talking about putting a lipo pack in there, I got thinking "Man this guys ready to drop some coin to mod this light".

Have you tested the lm317s like that before, what kind of sink did it take to get that kind of current out of it ?
Man, I honestly don't think it'll be up to it unless you have a honking big sink, but hey, it's free so it's worth a try.

According to my calculations, a 1ohm 5watt resistor should also fill the bill, but with the same downfalls as the diodes.
 

FRITZHID

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Last project I did with a 317 used a copper slug 3"long by 2"dia. The mass alone was enough for 5 min runtimes, never ran it much longer then that.
Yes I planned to test it before install.
I was looking at some of the 5A cccv power modules on eBay, but I don't have faith in them and don't really wanna throw $ away, yes I know they are only $6-8/pc but after A few failures, it can get costly. Anyone use those little modules with luck?
 

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Well, they can't be that bad. It's common proven tech at this point. I think for that price it's worth a try. If it fails just don't buy another.

The ironic thing is millions have used them with good luck without even knowing about it :p
 

FRITZHID

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Well, they can't be that bad. It's common proven tech at this point. I think for that price it's worth a try. If it fails just don't buy another.

The ironic thing is millions have used them with good luck without even knowing about it :p

Used them or devices like them. Can't guarantee quality on eBay crap, lol.
I'll probably check one out at some point
 

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