6 VOLT DC TO 12 VOLT DC CONVERTER TO DRIVE A SAT NAV ONLY.
While in France on holiday in BBM69 we visited Keith and Carol Fair, (See Holidays 2005). During our chats Keith Pointed out the possibility of using a DC to DC converter to power a Garmin Satellite Navigator. Some time later I obtained the hardware then forgot about the project. However, on sourcing a new charger for BBM I realized that the connection would be ideal for the sat nav project as well.
The charger is an AccuMate 6-12, it is a versatile, 4-step automatic charger and maintainer for 6V and 12V lead-acid batteries. (See photo 1).
In addition to the standard clips the charger comes with a fused lead that can be permanently attached to the battery terminals (See photo 2). The lead terminates in a Tamiya connector, I made up a matching socket and lead attached to the board of the converter. Care is needed as I was using the charging lead socket as a power out connection instead of a power in one. This reverses the normal male/female positive/negative pin arrangement. Connect the leads after the isolation switch as the converter draws a small idling current.
The DC to DC converter is a TRACO POWER THB 3-0512 This converts 4.5 to 9 volts DC to 12volts DC at a maximum of 250 mA. This has proved ample to run my sat nav. We had a proving run with the screen brightness and volume on 100%. I made it work hard re-calculating as we went along. I estimate that the converter uses about one amp. (See photo 3).
I have recently looked for the newest version of this converter (TRACO TEL 3-0512) and it is for sale at around £10.40 plus vat.
This version has a different pin layout but is basically the same. A 2 amp slow blow fuse is required on the input side. I chose to put this on the PCB but it could well be in the input lead. I also chose to add an LED to indicate power was on. Only because I had one in the junk box.
I attached the leads with a plug but they could just as well be soldered to the PCB. The output is through an in car connector to match the Garmin set up. I use the hole and grommet for the horn cable as an entry to the dash board. (See photo 4).