Charging an 18volt drill from 12volt batteries.

[Refueler]

I did not mean budget vs expensive, but that cordless drills with less voltage also have way less torque, so a 12V drill might not be up to the job. An 18V drill might be just fine through a boost converter at 20 volts or so, but if you wire it directly to 12 volts (without the boost coverter), it will be too weak.

Part of the problem is the batterys used ........... and of course the wiring / circuitry .... most are also brushed motors.

The combo means you need beefier brushes and bigger battery packs.

You could have a 12v drill pack a punch far higher than an 18v one - IF the drill itself is of different form ... put a decent LiION in - not the factory rejects that often get put in (properly balanced packs are not cheap !!) and a brushless motor ...

But even if you upgrade the battery as I did in my drill ... I went from a 14.4V NiCd pack to a 12.2V LiPo and the drill can handle jobs now it stalled on before ... (I did put a 4S pack in ... which gets charged to 16.8V ... but even at nominal 14.4V - it smoked !! so I dropped it back one cell to 3S).

But we are getting of the thread now ...

 

[William_H]

I did not mean budget vs expensive, but that cordless drills with less voltage also have way less torque, so a 12V drill might not be up to the job. An 18V drill might be just fine through a boost converter at 20 volts or so, but if you wire it directly to 12 volts (without the boost coverter), it will be too weak.

Not quite as simple as you say. A DC permanent magnet motor has large torque at low speeds drawing very large currents. At high speed the current falls because the back EMF rises with speed. A higher voltage can then give more torque and so more speed at higher speeds. This higher speed can be translated to more torque by gear ratios.
I think you will find that an 18v drill running on 12v ships supply will give very good torque at high load low speed assuming you can supply a good current ie heavy wiring from the ships battery. Certainly light load speed will be lower. Not much less torque. Worth a try. ol'will

 

[tjbrace]

Thanks to all for your advice. ?
I raised the mainsail with my drill and its li ion batteries last weekend. The machine became quite hot and produced some smoke. Definitely not up to the task, but it still drills holes.
Given up for now, may have to electrify a winch sometime.