How adaptable are cordless tool batteries?

Greenheart

Greenheart

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I was looking at an old square 6-volt lantern on ebay, identical to one my father kept in the car, back in the seventies.

My inclination is to buy it for the pleasant nostalgia, but I recall that it wasn't especially bright.

It occurs to me that I could probably fit a Bosch 18v battery in the lantern's compartment...

...so if I can source and fit an LED bulb matched to the Bosch's hefty output, I can give the old lamp a useful new lease of life.

What I do not know is how sensitive to their application, branded tool batteries are. I'm not worried about the warranty.

The same batteries fit a wide range of tools with varying demand, but is an unapproved application likely to shorten the life of the lithium cells inside?
 
For temporary use I find tool batteries great. The best are 12v for testing boat/car systems.

I’m no expert, but isn’t there an issue in draining lithium batteries too low? The chargers won’t charge them below a certain voltage. The tools themselves ‘know’ to shut down before this… or so I always thought.

A 5v power bank (which shuts itself down at critical voltage) coupled with an LED might be a better way of powering a lantern?
 
I have a cordless Dremel that refused to charge it's battery, it wasn't old either. I opened it up and soldered some decent gauge wire to the + and - where the battery used to connect. This wire is then connected to the boat's 12v supply whenever I need it. Very effective.
 
From limited experience of Lithium batteries in RC applications I am really impressed with their ability to deliver power. In an RC model the batteries will typically deliver their entire charge in about 10 minutes and recharge in a couple of hours ready to do it again and again. The only issue is making sure you stop drawing charge before the voltage drops ridiculously low.

Any technology that can do that is not likely to be damaged by any use you have in mind (subject to the proviso on voltage)
 
Because that's the only voltage that my Bosch batteries supply.

I've no idea if anyone even makes an 18v LED bulb. Just imagining what might be possible, as an upgrade to the distinctly last-century power of the lamp I'm bidding on.
 
Hmm, I realised that. I wouldn't have considered buying something effectively obsolete. I was thinking of what's possible, rather than use the old lamp with its rather weedy 6v supply. Although I daresay a 6v LED substitute bulb will give at least as much light and far better endurance, than the old incandescent.

As an aside, I had it at the back of my mind that one of the bigger Minn Kota trolling motors requires 36 volts...2 x 18. Only academic, as the big Minn Kota costs four times what my whole boat did.

I realise one would probably require about 60 kilos of lead-acid batteries to power such a thing for longer than a few moments, but it's an appealing idea that applications other than the tools they were designed to fit, could be driven by compact branded batteries, given a suitable adaptor for the terminals.

What I feared is that these costly batteries have a 'brain' that can detect when they're not connected to an approved application, and either cease working as self-defence, or melt down messily.
 
Probably not an issue with your lantern, but it's worth bearing in mind that batteries for tools a) have Ah capacities in single figures and b) are designed for intermittent, short duration use. You don't run an electric drill continuously for an hour; you might want to run an outboard for an hour. Assuming a wildly optimistic 10 Ah capacity, a 1kw (equivalent to 3hp) motor would draw 55 amps at 18V and exhaust the battery (as in flatter than a snakes belly!) in about 11 minutes. And that's assuming that you can use 100% of the energy in the battery, which you can't.

Just for comparison, I have a rechargeable vacuum cleaner. It has a power rating of 130 watts at 22V. The battery has a rating of 2Ah, and will run it for about 20 minutes of intermittent operation.
 
A number of the dc-dc converters have quite a wide input range, you can get outputs of 12v, 9v,6v etc easily. One I had was 12-30v input and 5v output for usb stuff
 
Converting things like torches using LED 'bulbs' is limited by the reflector and lens design.
It's Ok if you just want to throw light in the vague direction, but it's not like a proper reflector design focused on the filament of a bulb.

If you do just want a broad spread of light, then I've got a rechargable LED work lamp like this
Zinc Rechargeable LED Work Light IP65 10W 700lm
it claims 10W but is probably more like 6 or 7, but that's roughly like a 60 W tungsten bulb.
Runs for a few hours, charges from USB or 12V adaptor.
It's best used to shine at a wall to light a whole room tolerably well or for lighting a medium size area, as a work light, it casts strong shadows or blinds you.

If you want a more focussed beam then don't start from there, look at LEDs mated to lenses.

You can buy various lithium cells for about a fiver each and join the LiFePO4 anorak thread.
DC boost converter for a few quid.
Lithium charging circuit another few quid.

Alternative gizmo, Lithium 'USB Powerbank' , I bought one for about a tenner, a bit like this:
6000mAh mAh slim Power Bank USB Battery Charger compatible with iPhone | eBay
I don't trust the Ah ratings on these things, but it appears to take power from any crappy USB source and put out a strong 5V USB months later.
My Samsung (Spit!) tablet refuses to drink from it though.
 
That's all helpful and interesting, thank you.

Daverw, can it really be as simple as wiring the Bosch battery terminals to the appropriate down-stepping converter, and the converter's output to a car headlight bulb, or 12v LED? That certainly seems a temptingly obvious way to try it.

But, having this evening paid for the lamp, which at 45 years old is very clean and in its original cardboard carton, I may have too much respect for my youthful memories, to start taking it apart as if I was bored alone at home one afternoon in 1981. ?

Still, I remain warily interested in what fun may be had, wiring the portable power of cordless tool batteries, to non-standard items. ?
 
Tool batteries have protection circuits in them, they won't feel bad about feeding a puny led.
Many 12V car led bulbs have wide input voltage range, like 9- 30 volts and same bulb is meant for both 12 and 24V applications. Built-in stepdown converters.
 
I would not advocate using drill battery 18v It is relatively difficult to get a suitable socket for the battery to make contact. (I am thinking Ryobi here)
However this page Ebay led replacement bulb for flashlight | eBay
does show a bulb for use in an 18v light so presumably 18v LED.
What the page does show is replacement LED bulbs for flashlights. Almost certainly your light has the so called "prefocus". ie bulb has a ring or flange that is pressed into a socket to hold the body and a simple contact for pos. So with a 6v LED bulb fitted you could use a 6v lantern battery. or cobble up 4 d cells or wire up 2 Lithium 18650 cells in series giving 7 to 8 volts. (might be OK with 6v bulb) You would need a charge controller board and possibly a buck regulator to give 6v. All sorts of options ol'will
 
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