Ramblings of a Techno-Viking

Loscon 2010

As usual, I spent the Friday through Sunday after thanksgiving at Loscon. It's a general SF convention, with more authors attending than movie/TV people. The past several years it has been at the LAX Marriott.

Chaz Boston-Baden at the Anime LA table
Anastasia Hunter at Gaslight Gathering table

None of the panels seemed much of interest, so I did the usual looking through the dealers room, checking out the fan tables (where you can find out about other conventions), talking to friends in the halls, munching and talking in the con suite, some open filking, and talking and munching at the various room parties.

Victoria Shapero

I sold a couple of boxes of books to Marty Massoglia who has relocated to Tuscon after closing the store in San Fernando. He now only sells at conventions and online. Marty had fun looking through the "Faces of SF" book, and identified about 80% without cheating and looking at the names.

The only book I bought was the latest in the Kris Longknife series Redoubtable. Mike Moscoe (who writes the series under the pseudonym Mike Shepherd) looked pleased at how many copies of his books Book Universe had sold, and joked that I had one of the rare unautographed Mike Shepherd books when I mentioned my copy was in my car.

Allthing with other vikings
I'm the one with the beard and horned helmet
Shawn Crosby
Colleen Crosby

There is now a page for events I am considering going to. While mostly SF cons at the moment, I expect to add some RV related events. It is linked to in the sidebar.

Posted Thursday 02 December 2010 04:04 UTC
Last edited Thursday 02 December 2010 04:09 UTC

Upgrading the Converter/Charger, part 1

The Magnetek 6345 Converter/Charger that came in my Aerbus was never a good design, and is far inferior to what is available today. It's a single stage converter that feeds totally unfiltered and unregulated power to most circuits, and only a portion of the power is used to charge the battery slowly with a cheap and inaccurate voltage limiter. Not only is it slow charging the battery, it will overcharge it if left on too long.

To replace the original converter, I purchased an IOTA DLS-55 with IQ4 from BestConverter. This upgrades the output to 55 amps, and all of the output is regulated and will be used to charge the battery if there is no other load. With the IQ4, it is a 3 stage converter that will charge the battery quickly and then drop down to a maintenance level that should not overcharge the battery. Delivery was quick with the $0 slow shipping option -- I ordered it Wednesday evening and it arrived Saturday afternoon. The output terminals are a #2 recessed square that made me spend $9 on a tool to use it. (Home Depot keeps the tool in electrical, the tool department has no clue about it.) The IQ4 has the status LED and the connector on the same side, so you can't mount it showing the status LED and looking nice. The short cable included for the IQ4 has phone handset modular connectors, so it might be possible to use a phone handset cord to mount the IQ4 further from the converter. There is no provision for a battery temperature probe or adjusting the voltages from its preset values. Mounting in the space of the original converter will take some creativity, but it is smaller.

Since I haven't been running the generator enough to recharge the battery from whatever phantom loads there are, I took the new golf-cart batteries out and brought them home to charge. The dollar store jumper cables (purchased years ago when copper was cheaper) are undersized for the task.

See Converter2 for the rest of the install.

Posted Friday 10 December 2010 01:14 UTC
Last edited Wednesday 05 January 2011 03:54 UTC

I'm looking for some LEDs

[There are lots of articles about changing RV bulbs to LEDs that tend not be very technical, and lots of technical articles on LEDs aimed at people designing such bulbs and fixtures. This is my attempt to give RVers more technical information.]

Older RVs, like mine, use incandescent auto bulbs for interior lighting. My RV has four types of light fixtures, and I've found two types of bulbs in them: 1003 and 1141. Both use the BA15s base, as does the 1156. Unlike standard 120 volt incandescent bulbs, the life expectancy of these 12 volt bulbs tend to be longer for the higher wattage bulbs, as well as giving more light per watt. Here is information on such bulbs summarized from a couple of makers.

LEDs are diodes that emit light when they conduct. All LEDs are monochromatic (single color) and the color depends on the chemistry making up the diode. The chemistry also determines the voltage needed to get the LED to conduct, so red LEDs are about 1.7 volts, and blue LEDs are about 3.2 volts. White LEDs are blue LEDs that have a dye that fluoresces and creates additional colors. "Bright White" LEDs have less of this dye so more blue light gets through, "Warm White" LEDs have a thicker coating so there is more yellow-green light and less blue. (They tend to be less bright for the same power.) Some other colors of LEDs like pink also use this dye trick.

How bright a light is at a single point is measured in candella (cd). One candella is about as bright as a candle flame. The total amount of light is measured in lumens (lm). Both of these units may be prefixed with the metric prefixes, so you may see a LED rated as 5000 mcd, or about five times as bright as a candle. Larger LEDs used as lighting tend to be rated in lumens. All LEDs will have a display pattern, frequently a cone measured in degrees. Some LED bulbs are made of many small LEDs arranged to mimic the radiation pattern of an incandescent bulb.

White lights have a "color temperature" that measures how reddish or bluish the light is. Incandescent lights work by heating a piece of tungsten white-hot. Cooler is more reddish, hotter is more bluish. White LEDs, like fluorescent light fixtures, only produce light of a few frequencies that the human eye interprets as white since it only samples colors at three (or in rare cases four) frequencies. Sunlight is more reddish at dawn/dusk since it filters through more of the atmosphere. Bluish light can seem harsh and unnatural, since we are not used to seeing things in a (relatively) dim blue light.

LEDs are rated at a maximum current, normally 20mA for small ones. High power LEDs need to be kept cool by using heat sinks and maintaining air circulation. Beyond their rated current, they tend to overheat and have a very short lifetime. Usually they are most efficient at 80-90% of their rated current, as long as they are kept cool. There are several different techniques used to limit the current supplied to a LED:

  • No resistor. Used on disposable LED flashlights that use the battery and wiring resistance to limit current. Tends to have short lifetime.

  • Resistor. Cheap, power wasting, and not good in situations like an RV where the voltage may vary a lot.

  • Constant current regulator. Fairly cheap, wastes power.

  • Switching regulator. More expensive, uses less power. Can create interference with radio and TV signals.

Many LED manufacturers sort their high-power LEDs based on efficiency and color temperature. Low-quantity buyers get what others don't want, or pay significantly more for better quality LEDs.

While most LEDs are rated for 10,000 hours of use or more, some tests of cheaply made white ones have noticed the brightness is significantly less after 1000 hours. This is due to use of inferior dyes. Good ones will have 90% of their original brightness at the rated life.

Some of the places you can buy LED replacement bulbs online are: (I have not done business with any of them, please do not consider this a recommendation.)

Note that none of them give enough specs on their product to allow someone to do a good comparison. It would be nice to have light pattern, color temperature, light output, and efficiency at 10v and 15v. (If it can't handle that voltage range, it shouldn't be used in an RV.) Some of the specs given are doubtful, like having a warm white and cool white equal brightness. Due to this lack of usable specs, and differences in application and opinion, I'll agree with those that recommend buying a few and trying before making a large purchase to replace every bulb in an RV.

When buying a LED bulb to replace an incandescent, you need to find one that fits in your fixture and aims the light in the desired direction. The omni-directional ones almost always aim a good portion of their light where it is not of use.

While the efficiency of a white LED is not as much better than an incandescent as many claim, you need to take into account that the LED will usually have most of its output aimed in one direction. So a 100 lumen LED bulb may put more light on what you want to read than a 400 lumen incandescent. Colored LEDs, such as red used for tail lights, are much more efficient than using a filter over an incandescent light.

When I priced out making my own LED fixtures, minimum orders and shipping make that economicly impractical for less that 100, not including my time and discarded experiments.

Posted Thursday 16 December 2010 05:10 UTC
Last edited Thursday 16 December 2010 05:10 UTC

Robots and Spiders and Bots -- Oh my

Looking through the access logs for my web site, I find that most of the accesses are from robots and spiders and bots. Some of them I know about, others I've never heard of before. Somehow I don't think my site would be very relevant to "ichiro/mobile goo;+http://help.goo.ne.jp/door/crawler.html". Several of them have broken URL parsing code that assumes that all links are relative, "Purebot/1.1; +http://www.puritysearch.net/)" is one example. "Baiduspider+(+http://www.baidu.com/search/spider.htm)" frequently fetches the top-level page from multiple IPs, and doesn't get anything else.

There are also a significant attempts to break into php and/or sql, neither of which I have installed. One of them has "whitehat" it it's URL, as if anyone would be stupid enough to believe that.

Of the over 1700 IPs that have accessed my site so far, I think several hundred are real people that looked at my web site at least once. My use of a picture in an rv.net forum post accounts for a bunch of the IPs. Several people are checking back manually, and only one has subscribed to the rss feed via google.

Posted Friday 17 December 2010 02:42 UTC
Last edited Friday 17 December 2010 02:42 UTC

First "Mod" and Service

Since I don't know the last time my RV was serviced, I took it to a professional to be checked out and have the fluids changed. I used Alert Auto and RV in Saugus. There are other RV service places closer, but I decided to go with an independent that had good reviews on http://www.rvservicereviews.com/. The work was done promptly (3.5 hours) and they came in under their estimate. ($384 -- not cheap)

The gas tank is full for the first time since I owned it -- 47 gallons for just over $150. Since predictions are for prices to keep going up, I decided to fill now at $3.239/gallon at the Burbank Costco. The pump made me re-swipe after the first $100. Hopefully this will be enough to make it to Quartzsite next month for the Rubber Tramp Rendezvous.

My first "mod" was to remove the coffee maker. (I don't drink coffee.) This frees up some counter space in the kitchen.

Posted Wednesday 29 December 2010 00:38 UTC
Last edited Wednesday 29 December 2010 00:38 UTC