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Hi Simon
Sorry to keep nagging about this, but how did you testing go? Have you managed to do a write up yet? I'm still needing a solution for my old bike and adding another battery or etc as others have managed is not an option due to space considerations (no "back seat" to hide stuff under I'm afraid 
)
Location: Germany
Feb 7th, 2013 - 9:49 AM
Simon Jansen
I made up the little regulator circuit in the weekend and am testing it out now. I'll put a write up on my blog.
It's LDO regulator and it's pretty much made for car type applications. It will give you a fixed 5 volt output (at up to 1 amp) from an input voltage right down to 5.3 volts (up to 26 from memory?). Once it goes below 5.3v it will give you whatever the input is minus 0.3 volts.
I've been testing it using my ancient GPS unit (from the days when they were rare and expensive and power hungry) and that works fine. That unit shuts down when the input drops below about 4.7 volts.
The circuit is simple, one three pin device and two capacitors. It has reverse polarity, short circuit and thermal overload protection built in. It does need to be installed on a little heat-sink, especially at higher input voltages
I don't know what the voltage range is on a standard 6 volt car though? If someone can tell me that I can do some more testing.
All the details are at home and I can't remember the actual part number of the top of my head but I think I mentioned it earlier in this thread.
Simon
It's LDO regulator and it's pretty much made for car type applications. It will give you a fixed 5 volt output (at up to 1 amp) from an input voltage right down to 5.3 volts (up to 26 from memory?). Once it goes below 5.3v it will give you whatever the input is minus 0.3 volts.
I've been testing it using my ancient GPS unit (from the days when they were rare and expensive and power hungry) and that works fine. That unit shuts down when the input drops below about 4.7 volts.
The circuit is simple, one three pin device and two capacitors. It has reverse polarity, short circuit and thermal overload protection built in. It does need to be installed on a little heat-sink, especially at higher input voltages
I don't know what the voltage range is on a standard 6 volt car though? If someone can tell me that I can do some more testing.
All the details are at home and I can't remember the actual part number of the top of my head but I think I mentioned it earlier in this thread.
Simon
Hi Simon,
Your solution is certainly the best as no 6V battery should be allowed to drop under 6.00 V there's a lot of margin left with your 0.3 V regulator drop to give the required 5 V output. Then it is always advisable to get the 6 v source to the regulator from a good feed preferably close to the battery (both on plus and minus side) which will be cleaner and devoid from losses due to high beam etc. currents.
If one does that one should not remember to unplug the GPS when not in use!
By the way I guess your circuit is minus to ground Simon? That said with caution it could be used as well with plus to ground as long as the GPS is not connected to ground elsewhere (external aerial for example but who uses them?)
Renaud (another adept of the soldering iron
)
Location: Brittany
Feb 7th, 2013 - 5:28 PM
renaud
Simon Jansen
I made up the little regulator circuit in the weekend and am testing it out now. I'll put a write up on my blog.
It's LDO regulator and it's pretty much made for car type applications. It will give you a fixed 5 volt output (at up to 1 amp) from an input voltage right down to 5.3 volts (up to 26 from memory?). Once it goes below 5.3v it will give you whatever the input is minus 0.3 volts.
I've been testing it using my ancient GPS unit (from the days when they were rare and expensive and power hungry) and that works fine. That unit shuts down when the input drops below about 4.7 volts.
The circuit is simple, one three pin device and two capacitors. It has reverse polarity, short circuit and thermal overload protection built in. It does need to be installed on a little heat-sink, especially at higher input voltages
I don't know what the voltage range is on a standard 6 volt car though? If someone can tell me that I can do some more testing.
All the details are at home and I can't remember the actual part number of the top of my head but I think I mentioned it earlier in this thread.
Simon
It's LDO regulator and it's pretty much made for car type applications. It will give you a fixed 5 volt output (at up to 1 amp) from an input voltage right down to 5.3 volts (up to 26 from memory?). Once it goes below 5.3v it will give you whatever the input is minus 0.3 volts.
I've been testing it using my ancient GPS unit (from the days when they were rare and expensive and power hungry) and that works fine. That unit shuts down when the input drops below about 4.7 volts.
The circuit is simple, one three pin device and two capacitors. It has reverse polarity, short circuit and thermal overload protection built in. It does need to be installed on a little heat-sink, especially at higher input voltages
I don't know what the voltage range is on a standard 6 volt car though? If someone can tell me that I can do some more testing.
All the details are at home and I can't remember the actual part number of the top of my head but I think I mentioned it earlier in this thread.
Simon
Hi Simon,
Your solution is certainly the best as no 6V battery should be allowed to drop under 6.00 V there's a lot of margin left with your 0.3 V regulator drop to give the required 5 V output. Then it is always advisable to get the 6 v source to the regulator from a good feed preferably close to the battery (both on plus and minus side) which will be cleaner and devoid from losses due to high beam etc. currents.
If one does that one should not remember to unplug the GPS when not in use!
By the way I guess your circuit is minus to ground Simon? That said with caution it could be used as well with plus to ground as long as the GPS is not connected to ground elsewhere (external aerial for example but who uses them?)
Renaud (another adept of the soldering iron
)Hi Simon & Renaud,
Simon's approach is certainly the most electrically efficient but, the vast majority of forum users without any electronic background would probably baulk at making up a new lead just for use in the old car. I still think that the easiest route for the majority is a DC-DC up converter (or "buck converter" as the Aussies and Americans seem to prefer) giving anything between 10 and 24v from the 6v battery on load into a standard cigar lighter socket which would enable them to use the same lead for their GPS/'phone as they already do in their modern??
Ian Mc.
Location: Shropshire
Feb 7th, 2013 - 5:53 PM
A last update on this subject:
Simon's solution works like a dream! Even the vibrations of a 700cc single cylinder BSA haven't managed to destroy it yet.
Many thanks once again! 
Cheers
Pete
