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Thread: My Ghettomobile

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    My Ghettomobile

    I am posting it in this forum for the gadgets, home-made jerry-rigged setup. Light and GPSbars.jpgbatterypak.jpg

    The GPS is held on by a rubber band to a custom wood mount. The reason I did it this way is so I can take the GPS off the bike easily and put it my pocket to go into a into a store. I have a black flashlight that I am going to replace the blue one with. I used the blue one because I didn't know if it would work as I wanted, and that flashlight has a really loose switch which is why that piece of tape is there. The tape on the handlebars in other spots were where the old mini-lights were attached and I used the tape because I was using metal hoseclamps and didn't want to scratch the paint, I just have to cut the tape off. Also, the taped connections to the 9V adapter thing will be soldered. I really wanted to test this in the worst possible conditions before I started soldering and using shrink wrap. For me, the worst possible condition is Roosevelt Blvd, it is heavily tree-lined and pitch dark (on the pavement, you'd have to have a death wish to ride on the blvd in the street) and the tree roots push up the pavements and crack it up and leaves uneven spots and downed branches. It performed perfectly. I will probably also use black wire for both the positive and negative since it will match the bike. Also, that battery pack is going to be moved to my rack, once it arrives from Amazon.

    The drawback of using the GPS is it isn't very accurate with heavy cloud cover and the backlight kills the battery life. But I can attach the GPS to the computer and do stuff, though I haven't done any of that.

    So I wanted to put up a couple pics of my ghettomobile and how I had to make due with what I had and made it work.

    Chris

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    Senior Member tpolley's Avatar
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    i use my garmin etrex vista c via a handle bar mount. i haven't had any acuracy issues either by tree cover or cloud cover, and i'm under tree's 75% of the time. i also use my phone running map my ride and after a 25 mile ride both the phone and gps are within 2-3 10th's of a mile of each other. i don't think that's bad. i can get at least 2 hours out of a set of AA's with the back light on on the gps.

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    The reason I said it wasn't that accurate with trees and clouds is because it will say "ready to navigate 44ft" or "ready to navigate 4 ft" or 100 ft, all depending on how many satellites it can "see". This GPS is from the mid 90's from the Marlboro "miles" program.

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    Senior Member 01 CAt Man Do's Avatar
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    I'm a little confused; What is being powered by the 4-cell battery pack, the GPS?

    ...i can get at least 2 hours out of a set of AA's with the back light on on the gps.
    I would think the battery pack would last more than two hours but if the working voltage on the GPS is greater than 6volts that would help explain things.

    Some tips: Cheap torch holders are available from any Chinese web sites and work very well. Back in the day when the first LED torches were coming out I use to just use an old Marwi bar mount as a platform, sit the torch on that and use rubberized hair bands to keep it in place ( DiNotte style ). Worked very well with the smaller torches but a dedicated torch holder is better.

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    Quote Originally Posted by 01 CAt Man Do View Post
    I'm a little confused; What is being powered by the 4-cell battery pack, the GPS?



    I would think the battery pack would last more than two hours but if the working voltage on the GPS is greater than 6volts that would help explain things.

    Some tips: Cheap torch holders are available from any Chinese web sites and work very well. Back in the day when the first LED torches were coming out I use to just use an old Marwi bar mount as a platform, sit the torch on that and use rubberized hair bands to keep it in place ( DiNotte style ). Worked very well with the smaller torches but a dedicated torch holder is better.
    It's actually a 6 cell battery (it's double sided and has 8 cell spots) with 2 of the cells spots shorted that are wired to the flashlight which has a 5 D-Cell bulb in it. The standard 2 cell bulbs are bright enough to be seen, but not bright enough to be able to see the road conditions.

    I tried the Chinese made flashlights and they are really unreliable and not nearly as bright. The bulb I put in the flashlight is a Magstar 5 Cell Xenon bulb 5.5 watts 150 lumens 3100k. The reason I am using 6 cells on a 5 cell bulb is that 5D cells is 7.5V and 6 NIMH cells are 7.2V. Now, obviously, a 5 cell flashlight bulb can run on as low as 5V (Alkaline cells are considered dead when their voltage drops below 1V), but that tends to draw higher amperage which would more likely to overheat the element and shorten the life of the bulb.

    The GPS is just using 2 standard rechargeable AA batteries that fit inside the unit. My LBS had a device that was designed for phones that would mount the GPS just fine, but they wanted $30 for it, plus 8% sales tax.

    When my bike rack comes, I am going to use 12 C NiCad cells to make a battery pack for the light. NiCad batteries love to be deeply discharged, have MUCH lower internal resistance and perform well under high load and I have dozens of them from a hobby I have and that would give me a 25 watt hour battery (2 sets of 6 in parallel). What's more, they are all well matched, so I don't have the problem of a single cell reversing on me.

    Chris
    Last edited by christo930; 02-16-13 at 02:27 PM.

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