Replacing dead NiCads tools with mains power supply?

Several tools with rechargeable batteries have failed, one is a LIDL nailer/stapler, with a 18volt 1.3amp battery.

Could I dismantle the battery case and power the stapler from the mains using something like Maplin's

High Power Multi-Voltage Universal Laptop Power... * Universal input voltage for use all over the world with suitable travel adaptors * Adjustable output voltage DC 12, 14, 15, 16, 18, 18.5, 19, 19.5,

20, 22, 24V * 6 amp to 8.5 amp current; dependent on voltage setting
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Power Supply * DC 0 - 30V (2.5A), fixed DC 5 and 12V (0.5A) outputs * Current can be limited from 0 to 2.5A using the ?current? control. Triple Power Supply

OR something cheaper?

[g]
Reply to
george [dicegeorge]
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>> OR

Very unlikely to be usable. Peak current from nicads is far greater than the supplies you list.

The battery you quote would be 18v 1.3Ah which is NOT the same as 1.3amps

Just buy new nicads for it. Bob

Reply to
Bob Minchin

In principle its doable, but as Bob says in practice you'd need a high current supply. 2.5A is never going to work. Computer supplies provide a lot more current, and those in series could supply 30A. (You'd need to tweak the earthing, and convince them to operate)

Another option is to use an external lead acid battery that sits on the floor, with 12v tools. Any other voltage is also runnable if you're willing to open a battery. Lead acids don't charge happily from NiCd chargers.

NT

Reply to
Tabby

I had need of a bit of compressed air recently and ran a car tyre pump (normally run off the car cigarette ligher) off a 230/12V transformer with a bridge rectifier. It wasn't happy and didn't want to go above

0.3 bar, although it will happily do 4 or 6 bar for its intended use. The 0.3 bar was adequate for what I needed (leak testing with an ultra- sonic leak detector) so i didn't persist. I assumed the current draw was more than the transformer would supply for the maximum pressure part of the stroke. You could probably get it to run properly with some smoothing capacitors or a 12V lead acid battery on the outlet.

The same tranformer & rectifier arrangement has run a pressurization unit (which has a similar diaphragm pump) quite happily up to 2 or 3 bar (water pressure) when used on the 24V terminals.

Probably cheaper to get Ni-cads, as the man said, if you put any value on the time you'd spend trying to get such a lash-up to run reliably.

Reply to
Onetap

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>>>>>

oh yes, now I look again it is 1.3Ah which means 1.3 amps at 18volts for an hour but as you say it probably uses a lot more than 1.3 amps when its stapling.

Reply to
george [dicegeorge]

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yeah. Prolly peaks out at 30A or so.

Reply to
The Natural Philosopher

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>>>>>>>>>>>

Doubtful.. I have never taken one apart but I would imagine they use a motor to drive a stepped cam. This would lift a sprung hammer and drop it to staple. Much cheaper than using a solenoid and it doesn't take much power. However the motor is a reactive load so the initial start could be hundreds of amps for a very short time, the sort of thing a capacitor can supply. They could reduce the starting load by making sure the motor always stopped at the top of the slope and have it "level", this also reduces the time between pressing the trigger and the hammer dropping. The motor winds it back up post stapling.

Reply to
dennis

Or 13A at 18V for 1/10th an hour =3D=3D 6 minutes

Or 26A at 18V for 3 minutes

etc.

Reply to
Martin Bonner
2tr$7bd$ snipped-for-privacy@news.albasani.net...

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that electric nail guns use a solenoid.

Reply to
Martin Bonner

I know which one I doubt less.

MBQ

Reply to
Man at B&Q

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>>>>>

only £1`45 for a new battery, i'd feared it would be a lot more!

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snipped-for-privacy@walter-werkzeuge.com a reply within an hour!

Aldi service not as bad as I'd feared.

[g]
Reply to
george [dicegeorge]

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Motor resistance limits it to about 30A or so. They are not great motors in these things.

Reply to
The Natural Philosopher

It just reinforces by view - for DIY, only buy cordless tools where you

*really* need them. Or be prepared to replace them regularly.
Reply to
Dave Plowman (News)

There are ways to power it, but the expense and complexity of trying to charge lead acids or produce a high current mains supply would be prohibitive

Cheapest solution would be a couple of car batteries, connect them in series and hope for the best that the stapler doesn't demolish the wall, burn out or kill anyone within 100 metres.

Now if youy have a lot of cordless tools of the same Voltage, a nice DC ring main from trickle charged lead acids would be efficient. You could tailor the Voltage using cells of a similar capacity.

You might want to get your insurance company involved though :-)

HN

Reply to
H. Neary

I'm unclear what's prohibitive about pc psus, plenty available at no cost, and many can deliver 30A. Charging lead acids is hardly difficult.

NT

Reply to
Tabby

I think that 18V at 30 A would cost a bit, even with a Chinese Ebay solution.

Charging lead acids is simple. Try matching a car and motobike battery for a series circuit though. You may hit on a couple that are matched capacity wise, but I doubt it. You would probably overcharge one and leave the other [12V] flat, or reverse charge the 6V leading to a rapid demise.

Anything but vehicle batteries would come at a great cost unless the purchaser had inroads into an industry such as an alarm company or UPS supplier

Methinks the simplest solution is a Screwfix, Wickes or Toolstation catalogue[ 240 or 110V bits] , a long extension and perhaps a Bosh battery hammer drill for the times when One can't be bothered to to pay out the cable.

Never had a problem with lack of a power source, all my tools are 240V and I have a Bosh "professional" for the odd quick jobs.

Sadly my three year old Bosh is worn out, there is a lot of play in the chuck. Methinks it was due to using the SDS toolkit that was supplied with my Screwfix SDS drill & kit.

Havn't used the SDS drill yet, amazingly robust toolkit but I find the

6Kg drill a bit difficult to waggle about.

HN

Reply to
H. Neary

As already said, pc supplies dont cost a bean.

if I wanted to do this I'd probably go to a scrapyard and get 3x 6v batteries. Cheaper than a new set of nicads.

NT

Reply to
Tabby

5v at 30A is a bit different to 18v at 30A...
Reply to
Clive George

Roughly, it isn't linear. It'll be 1.3Ah at some rated current, and if you draw twice that current, you'll get a little bit less than half the time. If you draw ten times the current, you'll get noticably less than ten times the time.

Reply to
Alan Braggins

The only difference is needing to disconnect the wire from PCB to case so they can be put in series. Not much of a challenge.

NT

Reply to
Tabby

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