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240 volt rechargable power pack?

I need to find a rechargeable power pack to run power tools from, where no mains supply is available. Does anyone know who sells such a thing?

Thanks

Jack

Reply to
Jac
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PS.. It needs to be small and portable...

Reply to
Jac

They're called generators :-)

Seriously - if you need any amount of power (more than a couple of hundred Watts) for any period of time (more than 10 minutes), a generator is your only option.

Reply to
Grunff

Thanks for the reply. Actually, I only need to run 25 watts, and the power needs to last about 2 hours max... A generator would be unsuitable because of the location/working environment.

So... still looking for a 240v rechargable power supply...

Jac

Reply to
Jac

That's very easy - 1x car battery, 1x 12V inverter.

Reply to
Grunff

You need an inverter to produce 230v AC from some form of battery. It depends on what tools you wish to power, but say an 800 watt one that would do most will cost somewhere around 100-150 quid. And run off a large car battery for maybe a couple of hours.

So neither small, portable or cheap.

I presume just buying re-chargeable tools is out for your needs?

If you're using tools that can't be bought in re-chargeable versions, a portable generator is the way to go - petrol or diesel is a far better source of energy than any practical battery

Reply to
Dave Plowman

Like maplin.co.uk code N32AZ

Out of interest, what 25W device do you need to run which is only available in a mains version?

Reply to
Grunff

What power tool only takes 25 watts?

Reply to
Dave Plowman

Actually a small 25w solid state guitar amplifier. (a "tool" of my trade)...

Jac

Reply to
Jac

Are you the bloke who busks in Canary Wharf Tube Station in the mornings?

If so, can you learn some new tunes, please?

Reply to
Huge

That is going to be running on a much lower voltage than mains, DC too - so it wouldn't make sense to carry around a 12V battery, step up the voltage to 240AC, feed it into the amp which then steps it back down to probably 12V, maybe as much as 24V.

The most sensible thing to do is find out what voltage it runs at (if you're not confident opening it up and investigating, find someone who is) and use a car battery/two car batteries depending on the voltage.

Reply to
Grunff

Grunff, Thanks for the continued suggestions. It actually runs on 14volts after the mains transformer. I was initially trying to figure out how to add a rechargeable battery to the cirquit, but it's not as simple as it sounds because there is a split power supply: a positive one and a negative one, so it would require two batteries. Large echargeable batteries aren't cheap and I don't quite feel competent enough to mess around with the cirquit. But I guess I could possibly employ a tekkie to do thie job, if I can find one who knows what he's doing.

So, still looking for ideas..

Jac

Reply to
Jac

You are quite safe... The last time I did any busking was in 1979.... :-)

Jac

Reply to
Jac

Any decent music shop with a repairs dept would be able to fit a battery input for you. It would probably run happily off a small burglar alarm type lead acid battery, never mind a car battery.

Reply to
Tim Mitchell

If it runs on 14, it'll run on 12. You can either use a negative voltage generator, or much more simply, use two batteries.

You say rechargeables are expensive - go to a motor factor (not Halfords!), and buy two of the smallest car batteries they have. Mini (as in Austin) batteries are great. Should be about £20 each.

Make up a suitable box for carring them, and you're off. That provides you with your +/- 12V, and enough capacity to play all day.

If that's too heavy (I don't know how far you intend to carry this), get a pair of 12V sealed lead acids - but you really need at least 10Ah for this to be useful.

With a pair of batteries it's 3 wires, that's it. Much simpler than using a mains inverter.

Reply to
Grunff

Ac or DC? If AC use 12v car battery and battery charger, and a caravan invertpr.

If DC, you had better build your own. 240V DC is damned nasty - will burn like hell if you grab it.

Reply to
The Natural Philosopher

That's easy. Couple tow small 12v batteries in series to the big smoothing capacitor inside it, and forget the mains.

It will be running on about 20-30V probably internally.

It will also hum a lot less that way.

Reply to
The Natural Philosopher

+- 14v? and a split rail? That's easy - 2x12 cell Nicad pack.

Not hard to modify either. Need to turn the original transformer into a trickle charge circuit (couple of resistors) , and replace the AC switch with a DC one, running off the cells.

Trivial really. However the cells won't be cheap. Your best bet is to source 4x6 cell packs as used in model car racing, and use those - iften available on E-bay cheep, cos ebveryine wanst more powe than those toys come with, and upgrades.

If you are in east anglia, I'll have a go modding it.

Reply to
The Natural Philosopher

24 SUB C Nicads 1700Ma/h would weigh 3lb roughly, and sit in the bottom of the case. Dead easy to source in backs of 6. at 25W - about 1-2A drain - gettng on for an hour of playing at least. More money would net you larger capacity cells too.
Reply to
The Natural Philosopher
[lost the start of this thread - but somebody said in response to somebody else...]

Just noticed that TLC have an inverter on offer -- one for which the claim is made that it is suitable for videos so presumably the wavefrom isn't too bad ...

See:

formatting link
- 20 pounds

Don't all rush - I might have one myself.

Barley Twist (Please put out the cats to reply direct)

Reply to
Mr Fiendish

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