Battery Charger / Power Supply (Voltage, Amperage) Requirements for Phones, Laptops, Etc

When looking to buy a battery charger or power adapter for a device such as a phone or laptop, you may be unsure whether the one you buy will be sufficient or even blow up your device. Here are basic guidelines to keep in mind.

  • INPUT VOLTAGE TO CHARGER
    The input voltage from the outlet to the charger should match or be very close. In the US, this is 110 volts. Unless you are buying a charger in a foreign country where the voltage is different, e.g. 220 V, this should not be a problem.
  • OUTPUT VOLTAGE FROM CHARGER
    Like the input voltage, the output voltage of your charger should match or be very close to that of the device you are plugging it in to. The input voltage requirements of a device can usually be found on the device itself. At the bottom of my Lenovo Yoga 910 laptop, it says “Input 20 V, 2.25 A”. Therefore, this particular device needs a charger that outputs 20 V.
  • OUTPUT AMPERAGE FROM CHARGER
    The output amps from the charger should be equal to or greater than the input amp requirements of the device you plug it in to. My Lenovo Yoga laptop has an amp input requirement of 2.25 A.

    • A charger with lower amps may charge a device but slower. Or, it may not charge it at all and the power supply may just turn off as it would not be able to adequately supply the load (laptop).
    • A charger with higher amps may charge a device faster than it would with a charger with amps equal to the value specified for the device. A device will not blow up if the chargers amp output exceeds the amp value specified for the device. The device will just accept however many amps it can handle.
  • POWER
    Power (wattage) is calculated as V (Voltage) x I (amperage). P = V*I. Therefore, for my Lenovo laptop, the minimum power requirements to power it is 20 V * 2.25 A = 45 W (watts). Therefore, it can take any charger that puts out 45 W or more as long as the output voltage is 20 V.
Conclusion:
  • Input and output voltages should always match
  • Power supply amperage should be equal to or greater than the amps required by the load

Kitchen Remodel Project

  1. Preparation and Dust Management
    Covered floors with plastic. Put up plastic walls.
  2. Demolition
    Removed existing kitchen cabinets, wall, popcorn ceiling
  3. Wall Removal
    Removed a load-bearing wall by building two temporary walls, and installing a 10’ long 6”x12” special engineered wood beam and two 4”x6” posts. This opens the kitchen up to the dining room.
  4. Custom-Built Pony (Short) Wall
    Created two short walls by a post where a kitchen island was to be located.
  5. Plumbing
    Moved a copper sink drain and a cast iron toilet drain. Replaced outdated parts (copper and cast iron) with ABS. Small soffits were created as necessary. A hole was dug in the cement foundation to cut a cast iron drain pipe. The pipe was cut and capped off and the hole was refilled with cement.
  6. Electrical
    Since I removed a wall, I moved all wiring, outlets and switches to the short pony wall and rerouted some wiring between ceiling joists.
  7. Lighting
    The old light box with fluorescent tubes were replaced with 4 recessed lights.
  8. Popcorn Ceiling Removal
    The outdated popcorn ceiling was removed and retextured with an orange peel finish.
  9. Painting
    Walls and ceiling were repainted.
  10. Kitchen Floor
    The old vinyl sheet floor was removed and replaced with durable ceramic tile.
  11. New Cabinets
    I installed new kitchen cabinets
  12. New Countertops
    I installed quartz countertops
  13. Backsplash
    I installed a backsplash
  14. Debris Disposal
    I hauled all construction debris away for dumping at the San Leandro / Davis St. Transfer (Dump) Station.
Continue reading Kitchen Remodel Project

Sound Insulation in Residential Walls

There will always come a time when you wish the noise outside your room in your home could go away and that the sound that you are making, e.g. from playing music to watching a movie, could not be heard by people in other rooms. There is a unit of measure called STC (Sound Transmission Control) that indicates how much of a sound can penetrate a wall. According to Wikipedia, here are common levels.

STC What can be heard
25 Normal speech can be understood quite easily and distinctly through wall
30 Loud speech can be understood fairly well, normal speech heard but not understood
35 Loud speech audible but not intelligible
40 Onset of “privacy”
42 Loud speech audible as a murmur
45 Loud speech not audible; 90% of statistical population not annoyed
50 Very loud sounds such as musical instruments or a stereo can be faintly heard; 99% of population not annoyed.
60+ Good soundproofing; most sounds do not disturb neighbouring residents.

and here are different STC values by partition (wall) type.

STC Partition type
27 Single pane glass window (typical value) (Dual pane glass window range is 26-32)
33 Single layer of 1/2″ drywall on each side, wood studs, no insulation (typical interior wall)
39 Single layer of 1/2″ drywall on each side, wood studs, fiberglass insulation
44 4″ Hollow CMU (Concrete Masonry Unit)
45 Double layer of 1/2″ drywall on each side, wood studs, batt insulation in wall
46 Single layer of 1/2″ drywall, glued to 6″ lightweight concrete block wall, painted both sides
46 6″ Hollow CMU (Concrete Masonry Unit)
48 8″ Hollow CMU (Concrete Masonry Unit)
50 10″ Hollow CMU (Concrete Masonry Unit)
52 8″ Hollow CMU (Concrete Masonry Unit) with 2″ Z-Bars and 1/2″ Drywall on each side
54 Single layer of 1/2″ drywall, glued to 8″ dense concrete block wall, painted both sides
54 8″ Hollow CMU (Concrete Masonry Unit) with 1 1/2″ Wood Furring, 1 1/2″ Fiberglass Insulation and 1/2″ Drywall on each side
55 Double layer of 1/2″ drywall on each side, on staggered wood stud wall, batt insulation in wall
59 Double layer of 1/2″ drywall on each side, on wood stud wall, resilient channels on one side, batt insulation
63 Double layer of 1/2″ drywall on each side, on double wood/metal stud walls (spaced 1″ apart), double batt insulation
64 8″ Hollow CMU (Concrete Masonry Unit) with 3″ Steel Studs, Fiberglass Insulation and 1/2″ Drywall on each side
72 8″ concrete block wall, painted, with 1/2″ drywall on independent steel stud walls, each side, insulation in cavities

Note that a typical interior wall has an STC value of 33.

Some options for increasing the STC value in your walls:

  • National Gypsum makes a board called “SoundBreak XP Retrofit” which you place over your existing standard drywall. This increased the STC value from 33 to 36.
  • Adding fiberglass insulation in your wall increase the STC value from 33 to 39.
  • Adding another layer of 1/2″ drywall to your existing 1/2″ drywall and adding batt (pre-cut fiberglass) insulation between the studs will increase the STC value from 33 to 45.
  • For doors, try placing a soundproof curtain in front of it along with a door gasket / sweep and automatic door bottom or a draft stopper

 

Home Improvement Tool Tips

Cutting curves in ceramic tile, plywood, and plexiglass / acrylic

Cutting straight lines in ceramic tile is easy with a tile saw. But cutting curves, e.g. for toilet drains, can be tricky. Diamond hole saws are expensive. Instead, use a rotary tool (e.g. Dremel) with either a tile cutting bit or a tile cutting wheel.  Or, use a jig saw with a carbide grit blade. You can also cut wood and plexiglass using the appropriate bits as well.

Drilling a hole in ceramic tile

Drilling a hole in ceramic or porcelain tile can’t be done with a regular twist drill bit. Use a diamond or carbide-tipped masonry bit. To keep the bit from slipping off the glossy surface, put masking tape on the surface.

Cutting drywall

Cutting drywall can be done manually with a drywall saw but you can also use a power tool. Though oscillating tools and reciprocating saws can do the job, they won’t give a fine cut. Instead, use a rotary tool with a drywall bit.

Trimming drywall

If you cut drywall that is slightly too large to fit an opening, instead of trying to trim it with a utility knife or saw, use a rasp plane.

Measuring long distances by yourself

Put a nail into one end of the distance you want to measure. Put the end of the measuring tape into that nail to keep the measuring tape end in place. Pull the measuring tape end into the nail and pull.

Drawing circles

Put a nail into the material at the center of your desired circle. Hook the end of a tape measure into the nail. Hold a pencil against the tape measure at a distance equal to the radius of your desired circle. Rotate the measuring tape to draw a circle.

 

 

Cleaning Tips

Microfiber cloths (available at Costco)

  • for wiping kitchen, windows, glass, etc

Pressure Washer (available at Costco)

  • clean driveway
  • clean house exterior
  • clean fence

Clorox Disinfecting Wipes (available at Costco)

  • clean glass, including hard (mineral) water stains on shower glass
  • clean soap scum on shower tiles
  • clean dirt and soap scum on vanity and sink bowls
  • clean stainless steel appliances
  • clean kitchen countertops
  • clean microwave interior
  • clean faucets

Continue reading Cleaning Tips

Easily Unclog Drain with Hair and Grease Drain Opener

Recently my shower drain wasn’t draining water as fast as it used to. I normally use Drano but heard about the good reviews that Hair and Grease Drain Opener got which also comes with a money-back guarantee so I gave it a shot. Turns out it worked perfectly the first time. Here’s what I did:

  1. Poured 2.5 cups of the Hair and Grease Drain Opener liquid down the drain
  2. Waiting 6 hours (you can also just wait overnight)
  3. Boiled a pot of water
  4. Poured the boiling water down the drain
  5. Clog was gone

Starting a Small Engine Equipment with Choke Control

tl;dr

  • Put the choke in the off position.
  • Pull the start the engine.
  • If the engine doesn’t start after two pulls, put the choke in the on position and pull to try to start the engine again

Normally

  • when the engine has been off for a long time, e.g. after storage, you need to choke the engine by turning the choke to the on position and then pulling the rope to turn the engine on.
  • when the engine has been running and you temporarily turn it off for, say, 15 minutes, then the engine is still warm and you don’t need the choke to be on to restart the engine. if you restart a warmed-up engine with the choke on, the engine won’t start because there will be too much fuel going into the engine.

Continue reading Starting a Small Engine Equipment with Choke Control

Calculate Max Wattage a House Can Handle

If you open your circuit breaker, you’ll see a bunch of breakers with tabs. Each breaker controls a circuit for a certain part of your house, e.g. a circuit for the kitchen, a circuit for the bathroom, etc. Each breaker has a max amp rating, e.g. 15A or 20A. If you multiply the amp rating by 120 volts, you’ll get the max wattage the circuit can handle. e.g. 20×120 = 2400 watts. So if you have 14 circuit breakers that each can support a maximum of 20 amps (or 2400 watts), then your entire circuit breaker panel for your house can handle 14 x 2400 watts = 33,600 watts. However, this is all theoretical. If someone replaced a 15A breaker with a 20A breaker, you’ll have problems, e.g. a possible fire.

Continue reading Calculate Max Wattage a House Can Handle