Can you use battery charger to run drill?

[lago]

Wierd idea but I have a Ryobi 18v drill with 3 batteries: 2 totally dead and last one on last legs. I have the drill mounted in a jig to turn the case trimmer that I use to trim rifle cartridges.

The drill has 2 contact points for the battery. The battery and charger both have 3 contact points. I can't read any voltage on the 2 contacts that correspond to the +/- on the battery.

Anyone know what the significance is with the middle contact? Was thinking about making contact with it but don't want to do any possible damage to the charger in case I have the batteries rebuilt.

[frumper64]

I believe it is used by the charger to test the battery, but am not 100% sure. The outside and inside terminals should be the + and -.

[pelligrini]

The charger might not be able to provide enough current to power the drill under load. A multimeter would tell you which contacts are which.

You could make a corded connector out of one of the dead batteries. Remove the cells and hook up a properly sized power supply to the terminals.

[LCHIEN]

agree with Erik. charger won't run the drill under any kind of load - designed to charge at low current. You need a big power supply to run it. probably 18VDC with at least 10 Amps current capability.

[Cochese]

The charger might not be able to provide enough current to power the drill under load. A multimeter would tell you which contacts are which.

You could make a corded connector out of one of the dead batteries. Remove the cells and hook up a properly sized power supply to the terminals.

There's a third party supplier that sells cord to do this without the battery. Haven't seen it in awhile though, will look tomorrow.

http://www.lcdpayless.com/ryobi_one_power_adapter.php

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2

[ivwshane]

You could also try converting it yourself to A/C power. I want to do this to some old craftsman drill I have.


https://www.google.com/search?q=conv...&client=safari

[lago]

Thanks for the info. I was thinking about getting a transformer but not sure of amperage needed. Will be checking into that.

Lago

[LCHIEN]

for starters, take a look at a typical AC-powered drill. I have two, one is rated for 5A, the other for 2.2A. That gives an operating range of 270W to 600W.

Assuming your drill has similar torque and power they would also need 270-600W, from an 18V source, it would need then 15A to 33A. If its weaker than a corded drill then it may only require 10A. That's just simple physics. Don't forget that your transformer to drill cable to carry 30A needs to be 10Ga wire or so minimum for a run of 5 or six feet, or else you will lose significant fraction of the power in the wire. If its more like 10A, then probably 14Ga wire might do.

Also you know of course that a transformer converts AC to AC so you will also need a 10 - 30+ Amp full-wave bridge rectifier to convert that to DC. If you have a 30 amp rectifier it will likely need heatsinking so as not to burn it up. Selecting an appropriate finned heatsink would take another paragraph or two, or you could just bolt it to a piece of 16 ga. sheet steel about a foot square (educated guess) with heat sink compound between it and the rectifier. Good luck!

[chopnhack]

Some chargers have built in circuitry that checks for a chip in the battery before it starts charging. Chargers so equipped would be useless to you.

[LCHIEN]

Rechargeable cells for power tools like drills are usually in the 1.5 to 2.5 Amp hour capacity.
Slow chargers that take 15-16 hours usually charge at around .150 to .250 amps.
FAst chargers that charge in 3 hours or so usually should charge at about 1 Amp.
A drill will draw 15-30 amps as I said before. this should be obvious in that you can probably drain the battery in 10 minutes of hard use, compared to the 2,3, or 15 hours it takes to charge it. CHargers only put out continuously, around 1/10th or less the power it takes to run the drill continuously. The only way they can work is you spend a lot more time charging than you can working. Power is stored in the battery and released at high current when needed.

a regular charger will not usefully power a battery drill.

[cabinetman]

Here was an interesting post from a dear departed friend...

I'm using a 12V-5AH Sealed Lead-Acid battery used for toys or motorcycles.

I even use the 12V on drills that where originally 4.8V and it works (with higher speed and torque) already more than 10 years.

I connected the battery also to a 9.6V jig saw and it works better than the original.

When I'm in the garage, I connect the drills to a step-down transformer rectifier that can supply 12V up to 300W (25A)...I measured the power consumption with locked shaft and got 7~8 Amp (same as they do on the shop vacs to get "6.5 peak HP" ).

I think that any transformer that can supply 10A (120W) will do the job...

Regards

Niki
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[capncarl]

Ryobi 18v batteries are about the cheapest batteries on the market today. If you have to go to any expense to convert this drill to ac you could well exceed the cost of a replacement battery.

Capncarl

[cabinetman]

Ryobi 18v batteries are about the cheapest batteries on the market today. If you have to go to any expense to convert this drill to ac you could well exceed the cost of a replacement battery.

Capncarl

Makes you wonder why they don't come both ways.

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[jking]

Makes you wonder why they don't come both ways.

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Several years ago, Skil had a cordless drill that came with an alternate power cord setup. If the battery ran down, you could take it out & plug a corded adapter into the drill, plug the other end into an outlet & you're running again. It didn't last very long, though.

[lago]

After reading the last few posts, I think I will just modify my jig to use my corded DeWalt drill. If I need to use the Ryobi cordless in the future, will probably have a battery rebuild.

Lago