Saving Space with an overhead shop vac

I have a 12 amp wall mounted shop vac, but I’m not allowed to screw into the walls of my rental garage. I also want to use it at the same time as other high power tools, like my table saw or drill press. This is a problem, because if the tool and the vacuum are both running on the same 15 amp circuit, the breaker trips. My rental garage has a single 15 amp circuit for all of the outlets. Except this one, which is on the same circuit as the lights.

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I doubt I’ll be opening or closing the garage door at the same time as I run the shop vac, so putting the vacuum on the lighting circuit solves a lot of problems.

I bolted a 2×4 to the metal rail with 5/16″ screws and nuts and then mounted the vacuum to that.

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My countsink bit was too small to fully fit the head of this 5/16 screw, so I drilled a 1/8″ pilot hole, then used my 5/8″ spade bit to drill a small impression before drilling with 1/4″ and 5/16″ bits and then using the countersink bit for the bottom of the conic section.

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I needed somewhere for the hose, and the mount needed stabilizing along the Z axis so it doesn’t wobble when you turn the vacuum on or off, so I put another 2×4 on the other side for the hose mount and connected them together with deck screws for stability. I wired up a switched outlet that I can (just barely) reach from the ground, with an extra outlet in case I want to plug anything else into the secondary circuit.

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Now I can run the vacuum at the same time as other high current shop equipment because they are on different circuits, and it’s off the floor and out of the way.

A video of the same content on YouTube:

 

Building a lofted storage shelf

The new garage I moved into does not have an attic to store all of our boxes. But, it does have 10.5 foot ceilings. I am converting some of this overhead space into usable storage by building a series of lofted overhead storage shelves and platforms (the largest is 4′ x 8′, or a piece of plywood in size).

This post will explain how to build a single lofted shelf (to go over a table or desk for example). My primary support material is 2×4 studs, and the shelf material and some sheathing brace pieces are made from 3/4″ (nominal, 23/32 actual) subfloor plywood.

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Improve your photos by using professional framing choices

The two photos below are of the same subject. The first photo was taken by an amateur photographer, making rookie mistakes. He decided to use a vertical layout to capture the pool, but this chopped off the near corners. He does not include the sky or a visible horizon, and the background is an uninteresting wall of green. The center of the photo falls in the water, with no interesting details.

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Below is the same subject photographed by a professional photographer. Notice how the landscape orientation she has chosen complements the vertical layout of the pool. By moving to the other end of the pool she includes sky and an implied horizon. Notice also how she has placed the vanishing point at the splash of color inside the pool shed to act as a focus point. Simply by changing the focus point, orientation, and camera location the subject is made to sparkle!12 1293 Berkeley Pool

Sexist Google Image Search filters

I was sitting next to my wife who was goggling for images of haircuts. (I have to admit,  I’ve never performed this type of search before tonight….)  She showed me a few of her search results, and I noticed that she had some super cool search filtering options across the top of her Google image search results that I had never seen before. (I had thought I knew all the tricks of how to use Google image search…..I was wrong.)

As it turns out, I just hadn’t been using the right search terms, like “for women”. Here is an image of what I’m talking about.

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That’s right, when you search for “short wavy haircuts for women” you can filter by “over 40”, “over 50”, or face shape!  But why can’t I filter images of men by age or face shape when searching for  “short wavy haircuts for men”?

For that matter, how come I don’t see any men when searching for “short wavy haircuts”… Continue reading

Sink Drain Sizes

Repeat after me: 1-1/2″ for kitchen sinks, 1-1/4″ for bathroom sinks. Or, you could construct an adapter like this….

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Follow along with me from left to right:  we start with a 1-1/2″ to 1-1/4″ drain and trap connector, which is required to connect to the steel drain pipe. But then things go downhill, as we have a 1-1/4″ to 1-1/2″ adapter, a 1-1/2″ (kitchen sink) P-Trap, followed by a 1 1/2″ to 1 1/4″ adapter to connect to the bathroom sink drain.

I’d like to think that somebody decided they really wanted a larger P-Trap on the master bath sink…but I suspect that the plumber only had a kitchen sink P-Trap in his truck and didn’t want to make a special trip

Since I needed to change the length I went ahead and used 1-1/4″ throughout. I think it looks a bit nicer. (I also sealed the hole into the wall with expanding foam while I was under the sink.)

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Secret birdhouse camera

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This ratty old birdhouse has a secret. It was actually an “outdoor enclosure” for an indoor WiFi security camera (D-Link DCS-920). The birdhouse worked well over the last five years protecting the camera from the weather. (I lost one power supply, which hangs outside the birdhouse, so I waterproofed the replacement with hot glue and lots of layers of electrical tape.)

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It looked better five years ago (the perch was gnawed off, probably by a squirrel), but it was never operable as a birdhouse, as the entry hole is covered by clear Plexiglas and acts as the viewport for the camera.  It’s basically the opposite of Dennis Nino Clasen’s birdhouse camera:

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Now that I’m retiring it, I can post the secret on the internet. It was relatively difficult to notice the camera inside the birdhouse. Over five years of operation, I only know of one person who noticed that it was a camera (and then called over the whole crew to take a look…)

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I did feel (only slightly) guilty about the number of birds that flew to the perch and tried to go inside….

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One of these animals is not the same….

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96 °F charging

I tested my 80% profile (limited to 25A) on a very hot 92 °F day. The chargers reached 65 °C but did not shut down due to overheating. (My 80% profile ends charging when the draw reaches 10A.)

A charger temp of 65 °C is still much hotter than I would like, so I don’t plan on charging in 90 °F heat very frequently.

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Cooling Ducts – Mostly successful for charging at 30 Amps

Adding cooling ducts to my chargers was mostly successful. I am still able to make the chargers overheat (and shutdown) when charging in hot 95-100 °F outdoor temperatures at the maximum 30 A rate, but it takes them longer to do so. I can work around this by charging at a lower rate or delaying charging until the day is cooler.  I have my “80%” charging profile set to use the recommended 25A rate instead (and may even lower this depending upon the results of future temperature logging sessions).

However, on rare occasions I may need to charge as fast as possible for one to two hours at a charger away from home (to extend my range). I would typically not be making long trips in 100 °F temperatures, so I tested charging at the full 30A rate on an 80°F ambient day, which generated the following graph. (I have two chargers, so they each have their own watts and temperature line.)

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Current imbalance with dual chargers – TSM 2500 / EVCC

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This graph shows the temperature (in C) of my two chargers, as well as the watts of power they report providing over time (in minutes) as they charge the Nissan Leaf battery pack in my truck.

For the first 23 minutes of the charging session, both chargers are putting out 12.5 amps (at around 129.5 volts) or around 1600 watts. The 12.5 amps is limited by my MaxC (maximum current) setting of 25 amps total by the Thunderstruck motors EVCC (Electric Vehicle Charge Controller). So in the first 23 minutes, the amount of power drawn is limited by the chargers.

From the 23 minute mark until the end of charging, the battery bank begins to accept less than 25 total amps (because the cells are getting charged, and the pack voltage is getting closer to the MaxV (maximum voltage) that the chargers are putting out.

So for example, at minute 32, charger A is still supplying 12.5 amps (1600 watts), but charger B has dropped down to supplying around 4 amps (500 watts).  (The difference in power output also has an effect on the temperature of each charger, shown in the yellow and blue lines…) I have been having overheating issues causing my chargers to shut down, hence the detailed logging….

My hypothesis is that the power difference is due to one charger providing a slightly higher actual voltage (e.g. it’s voltage sensor reads just slightly less than the other charger) so although they both claim to be limiting voltage to 129.5 volts, one of them is actually putting out a slightly higher voltage than the other, which causes more current to flow from the “hot” charger to the battery bank.

This graph is evidence that the ThunderStruck motors EVCC does not do “active” balancing of the chargers. I suspect that the EVCC probably just sets the “maximum” amps and volts for both chargers and then turns them loose.

The chargers report back the amps/voltage/watts they are providing, so the EVCC could in theory dynamically change the maximum current settings on the “hot” charger to only provide an amp or so more than the “cold” charger, more evenly balancing the load. However, this would add complexity and require extra code and testing. And as you limited the current provided by the “hot” charger the “cold” charger would start providing the extra current, and over time the identity of the charger providing more current would switch back and forth.

This active balancing would only be needed (or be useful) when the battery pack was drawing less than the maximum current capacity of your charger array (near the end of the charging session, in the 80-100% SOC range).

The limited potential benefits to this added complexity could be:

  1. Your chargers (and wires) would presumably stay closer to each other in temperature (only really an issue if you are suffering from overheating, which is why I was logging this data in the first place).
  2. If your chargers are more efficient at a lower current, it could save you some energy / heat. (Conversely, if your chargers are most efficient at full current, it may be better to run one charger at full current and just use the other charger to “fill in” any extra current needs.)

In short, I can understand why the ThunderStruck motors EVCC does not perform active balancing (at least with the version of the firmware I’m using — v2.3.1), but I would certainly be willing to test a current balancing feature in future firmware releases.