Cordless system with "fake battery" adapter?

[thewinelake]

Do any of the cordless tool systems have a way of using them when all your batteries are flat? eg. a "fake" battery that contains an 18v transformer and a long mains cable?

 

[foxhole]

Do any of the cordless tool systems have a way of using them when all your batteries are flat? eg. a "fake" battery that contains an 18v transformer and a long mains cable?

No point

 

[JohnD]

My BiL, who has a couple of boats and a motorhome, takes all my old cordless tools and runs them off a wander lead on the vehicle battery. These are tools that would otherwise be binned when the battery or charger fails. he solders on connections. He says they accomodate voltage fluctuations, but they are essentially free and don't need to last long.

 

[Ryler]

Do any of the cordless tool systems have a way of using them when all your batteries are flat? eg. a "fake" battery that contains an 18v transformer and a long mains cable?

Yes Dewalt have such a device.....
Available in 240v or 110v.

It just means that where power is available, you have the option.
Personally I rarely use 110v. The lack of power and lugging a transformer around are the big cons.
Dewalt also do 110v chargers.

 

[thewinelake]

Thanks! I see that's quite an expensive item. I like the idea of making one's own adapter from old batteries.

 

[thewinelake]

My BiL, who has a couple of boats and a motorhome, takes all my old cordless tools and runs them off a wander lead on the vehicle battery. These are tools that would otherwise be binned when the battery or charger fails. he solders on connections. He says they accomodate voltage fluctuations, but they are essentially free and don't need to last long.

I wonder how much current they draw at 18v?

 

[opps]

Why not just buy a second battery? Probably the cheaper option.

If you do decided to DIY one, you will need an old battery for the housing anyway, and then you will need a suitable transformer and circuitry to step down from 230v to 18v

 

[thewinelake]

I already have 2 batteries. Sometimes if one is doing intensive work (or has been careless with charging regimes!) one can get stuck. I had naively assumed that a mains adaptor would only be about £20 or so, so a useful insurance policy, but I was wrong!

 

[big-all]

bosch do a 10.8/12v one
https://www.powertoolworld.co.uk/bosch-aa1-battery-adaptor-10.8v-12v

 

[thewinelake]

Preferably looking for a “power 4 all” connector, but thanks

 

[thewinelake]

A battery seems to hold just 27Wh. I wonder if one could assume it will last 30mins continuous so I’d need to find about 50W transformer? So just 3A? That’s not too bad. But it’s odd that the mains powered tools (eg jigsaw) tend to be about 700W!

 

[big-all]

a 2ah battery holds 2x18x60=2160w
so 10 mins at say 216w or 3 mins 720w knock off perhaps 10% for losses so perhaps 650w

you would need a 25-30 amp source or around 450w output for this drill as an example
https://products.dewalt.co.uk/powertools/productdetails/catno/DCD795M2/
look at specification its 370w output

 

[catlad]

Hi Big all
I was interested in the 10.8 adaptor for a moment, and then I read the spec and its not for power tools its for usb charging or things with low draw.

 

[big-all]

Hi Big all
I was interested in the 10.8 adaptor for a moment, and then I read the spec and its not for power tools its for usb charging or things with low draw.

ahh must admit i wondered how 2x3.6 cells would give out 10.6v without any visible electronics

thanks for the helpful correction

 

[thewinelake]

a 2ah battery holds 2x18x60=2160w
so 10 mins at say 216w or 3 mins 720w knock off perhaps 10% for losses so perhaps 650w

you would need a 25-30 amp source or around 450w output for this drill as an example
https://products.dewalt.co.uk/powertools/productdetails/catno/DCD795M2/
look at specification its 370w output

That's a lot! I think this idea is a non-starter for me.... It's cheaper just to buy a mains version and a battery powered version if I've too much charge anxiety!

Although, hang on a minute, why are you multiplying by 60? Surely the battery capacity is just 2 x 18 = 36Wh. If that's all gone in 10 mins, then that would be 36 * 60/10 = 218W. My thought of a separate transformer supplying the fake battery at low voltage is a bit of a non-starter, as we're looking at about 20A.

Still, fun trying to work it out!