My question concerns the current output of the chosen converter. The battery output is labeled 2. I can't find the amp usage on the various tools' labels. Since the tools are presumably rated at different amperages, how important is it that I get a converter with the appropriate output current? After a quick google, I've located several 18v converters. This site has a plethora of them to choose from and those I've looked into have detailed specs.
So if I assume that the most powerful of the hand tools is rated at 8 watts, I should find a converter that is rated at least that high and go for it, right? I feel so completely ignorant. I learned Ohm's Law in high school 35 years ago but haven't used it since so I have no idea how to make this decision.
Any help would be appreciated. Also, being completely new around here, I may have put this in the wrong forum section. Please let me know if that is the case.
Thanks, Jerry in Knoxville. Ripshod said:. Click to expand At stall you could expect to see peaks of 30 - 40 amps on a 18 volt drill. Your best bet would be to do what I do and just by a cheaper 18 volt generic drill battery and refit the new cells from it into the old Bosch battery case. Hello, I have a 9.
I have to run a cord to the battery, but i can still carry it around with me. It's hard to beat as the original cells were rated at around 2Ahr and the smallest lead acid battery i have is rated for 7. I also use an automobile jump pack made for jump starting cars. These are a bit expensive but they usually have at least a 15Ahr battery inside which works really nice.
You definitely have to get enough current to run the drill or it wont be able to handle heavy jobs like putting screws into studs or similar. You can measure the stall current with a clamp on meter that works with DC make sure you get one that can handle DC or it wont work at all. My drill requires about 35 amps and if i try to power it with a 10 amp supply it doesnt have enough torque so i have to use a 12v computer power supply that puts out enough current to handle the heavy jobs.
An 18v drill might run to some degree on a 12vdc power supply, but i havent tried it. If it doesnt, you might try a 12v lead acid battery in series with a 6v lead acid both of the same ampere hour rating. You will have to keep an eye on the voltage of both batteries however as to avoid discharging one too much. It gets a little expensive trying to build an 18v 40A power supply that runs directly from the vac line.
It's not a tremendously complex circuit, but the parts start to run into some money when you need 40 amp diodes with heat sinks and a nice inductor to handle that much current plus some overhead. If you can find a nice heavy duty 18v transformer in surplus or something you might try a bridge rectifier circuit heavy current diodes and some capacitance and that would do it too. Might want to go with a 16vac output though so the voltage doesnt go too high.
This would be a simple circuit made of the transformer, four 40 amp diodes with two nice size heat sinks, and a decent size capacitor probably made from a few in parallel. I converted one of my drill battery packs by simply removing all the cells inside and running heavy wires to the internal connections for plus and minus and ran the wire through a small hole to a cigar lighter plug. Thus, i can pull the pack out of the drill at any time and use the other pack if i ever rebuild it again.
Last edited: Jan 13, I'm getting tired of getting raped when I buy those replacement batteries, too. Stick 'em in a small canvas bag, and make a 8ft cable to the tool in question. MikeMl said:. I had a 12 volt craftsman that had bad batteries so I wired in a cord and cigarette lighter plug to it so I could use it with my jump starter power pack. It is most commonly in amplifier systems, various power adaptors, soldering stations, testing equipment etc.
Any situations where the input AC voltage has possibilities to fluctuate or if the AC voltage drops significantly, the output AC voltage across the transformer also gets dropped. To address this isse, an additional setting is provided for different input voltage levels.
Another limitation is low conversion efficiency. The transformer gets heat up and the waste unnecessary energy.
The Transformer is heavy stuff which unnecessarily increases the weight of the product. Due to the transformer, the bigger space is required inside the product to fit the converter circuit or at least the transformer. To overcome these limitations, SMPS or switch mode power supply is a preferable choice. Get Our Weekly Newsletter! Helena St. Related Content.
Driverless LED Lights. Comments Log in or register to post Comment. Wire the primary winding of the transformer to the main AC supply. This transformer connection has no polarity and may be connected either way.
Connect the secondary winding of the transformer to a full wave bridge rectifier package. The transformer connections and the connections to the marked inputs of the rectifier package have no polarity and may be connected either way. This rectifier can be built up from 4 discrete rectifying diodes, rather than using a rectifier bridge package.
The diodes will be marked to show a positive cathode end and a negative anode end. Connect the 4 diodes into a loop. Connect the cathode of diode 1 to the cathode of diode 2.
Connect the anode of diode 2 to the cathode of diode 3. Connect the anode of diode 3 to the anode of diode 4. Connect the cathode of diode 4 to the anode of diode 1. Wire the discrete rectifier to the transformer secondary.
The transformer secondary should be connected to the cathode of diode 3 and the cathode of diode 4. There is no required polarity for these connections. The positive output of the rectifier is at the point where the cathodes of diodes 1 and 2 join. The negative output of the rectifier is at the point where the anodes of diodes 3 and 4 join.
Attach a smoothing capacitor. Attach a polarized capacitor across the output connections of the rectifier. The positive terminal of the polarized capacitor must connect to the positive output of the regulator.
This capacitor should be sized such that the capacitance in farads F is equal to 5 times the current to be supplied by the AC DC converter divided by transformer secondary rating times 1. Frequency varies from country to country, but is typically either 50 Hertz Hz or 60 Hertz.
Provide the final regulation. Choose a commercially available voltage regulator designed to control the output of the AC DC converter to the desired output voltage. The regulator will be a 3-pin device. The regulator pins will be a common, an input from the smoothing capacitor and an output of the regulator. This regulator output also will be the final output of the completed AC DC converter. There probably will be a noise suppression capacitor specified in the regulator manufacturer's data sheet.
Acquire and install that capacitor per the manufacturer's data sheet for the regulator. Then clip tip or female plug off the rand and separate the wires. Run a voltage test to identify your ground. Connect the black wire from the back of your stereo to the ground. Then take the red and yellow wires from the back of your stereo and connect them both the with the positive or hot wire from your adapter.
Use heat shrinks to cover and separate wires.
0コメント