For my bicycle touring, I have a Cannondale touring bicycle, Garmin GPSII+, Toshiba Libretto 50CT 1.8 pounds computer and DeLorme Street Atlas 6. I have extracted the entire US CD to the hard drive and I install a virtual CD drive for Topo US CD. I have a 6 gig HD. I can get voice in the car with a CD to tape adapter. I use the GPS for traveling and when a route change or location is needed I will look at the Libretto's screen. The Libretto is most useful on new routes. The GPS is sufficient for establish route that can be uploaded prior to starting. With the external battery described above, I expect more than a days use. Previously I used a 7 pound GRID that required 24 volts external battery supply. Pictures are at the bottom of this page.
My external battery supply is a 12 4Ah Gel cell. The Libretto mail list at http://libretto.basiclink.com has discussed three ways to use 12 volts external supply for the 50CT. I am using all. The cheater circuit link to below, I tried first. The load was to much for the one amp diodes, I bought a car adapter to use, thinking that it had more reliability. I found that my unit shut down when the supply fell to 11 volts. ( the Libretto will operate to 9 volts. I replaced the diodes with 3 amps and continued to used the 9 volt battery cheater system. Another poster suggest using the AC adapter for the cheater voltage. I made a four position jack that terminal to one Libretto plug. The sequence is to plug the four in one into the Libretto, next plug in the DC plug from the adapter, next the dc from the battery, then unplug the DC adapter jack. If the right green light is on, you are on external power. The Battery and adapters is in the bottom of my standard handlebar bicycle bag, a sheet of form rubber is between the battery and the Libretto, a perfect fit. I will use the adapter on my six day trip later this year, it will save the need to carry a battery charger on my bicycle trip. I will stay in hotels. With the four jacks, I can power the GPS and my light system from the gel cell also.
DC jack adapter. The insulator are 1/8 plexiglass. The internal pin were turned from 10-32 threaded brass rod. A piece of 1/2 steel was chucked in the lathe, drilled and tapped for 10-32 thread. A 1/2 length of the threaded rod was turned into the threaded hold and a nut locked the rod in place and 3/8 of the rod was turn to .120". The plexiglass was saw in to a 1 1/4 strip and cut to 1" long. the plate were pin with 2 roll pins. Four #21 drill holes were drilled, tap drill for #10-32. The plates were witness marked, then separated. The top plate was drill to 1/4 and expansion reamed to the plug OD. The next two were drilled to 5/16. the fourth was tapped. the fifth plate was drilled to 7/14 to chear the nuts. A piece of weather stripping brass was cut to formed a ground between the top and next plate, with a tab extending for soldier. The bottom of the pins which has lock nuts one each, were connected via a wire to the positive wire, and the brass tab formed the ground.
To jumpstart the Libretto for using the 12 volt Gel-cell battery, I plug the muti jack into Libretto, then plug the wall adapter or the auto adapter (being fed 12 volts from the car or Gel-cell), into the muti jack. The power light should come on. Now plug the Gel-cell into the muti jack and unplug the wall or auto adapter, whichever is being used. the power light should stay on.
8+ hour battery: Air/auto adapter, the Libretto. My mail order source of my gel cell batteries, Hosfelt Electronic 888-26464. 6 volt 4Ahr are $12.95 ea. and the 12 volt 4Ahr are $23.95 each.
This auto alternator tester is great for measuring the battery voltage. a series of five light indicate the battery status. light number 4 is marked low out for an alternator is a fully charged indicator for my Gel-cells. Another indicator is to allow the wall adapter to charge the Libretto battery and the Gel-cell at the same time. When the orange light turns green, both battery are charged and the Gel-cell lights #4 on the tester. the tester was bought in an auto supply store some where in New England as I was on my 750 mile bicycle trip with moving map.
