12v to 6v

[Dave_Rolfe]

Is there a simple way of wiring up a connection to run a 6v battery from a 12v boat supply. Ideally I would like to be able to plug it into a normal 12v outlet socket a la cigarette lighter type.

I want to be able to run a radio that can receive short and long wave transmissions from the boats 12v supply to lose the risk of always having a flat battery when I want to use the radio. It would normally take four C cell 1.5v batteries.

 

[jwilson]

Put 4x NiMh rechargeables in the radio, and make up a lead to the 12volt supply with a simple resistor in it, to limit current to say 200 milliamps even if the batteries are dead flat. From 'O' level physics about 50 years ago that should be 60 ohms. A 5 watt rating resistor should be fine and won't get too hot. Just don't leave 12 volt power on forever or you will cook the batteries - 12-24 hours should recharge them if flat, or half an hour top them up if near full charge. Crude but will work and very, very cheap. And you will find the NiMhs will power your radio far longer than throwaway cells so you'll have flat batteries far less frequently.

Waiting to be shot down by proper engineers!

 

[ccscott49]

Go to maplins, you should find just what you need there, ask.

 

[Billjratt]

Go to maplin or RS components or whoever, and get a 7806. This is a 3 legged device which will give 6.0 volts stabilised output from an input voltage of about 9 -17v There are various sizes to account for current capacity, so I would suggest either a big one, or one on a heatsink. Charging batteries using bogus equipment could be dangerous (fire hazard) and should be avoided. If interested there are many devices in the "78" range, the last two figures being the output voltage. The connection is simple ; one input to positive, a common negative, and the output.... easy-peasy. I use several on the boat and in the shack for (normally) hand-held equipment.

 

[Vara]

The Grundig Yacht Boy wont work on NiMH as they dont have enough volts to overcome the auto switch off. The only downside of a very good little radio.
And AFAIK inserting the ext power isolates the internal cells.

Unless anybody knows a way of overcoming this problem which doesn't involve taking it to bits.

I bought a 12-6v reducer in a French petrol station for very few euros which solves the in boat prob.

 

[Solent sailer]

Maplins do a nice switchable dc to dc converter cigarett plug on one end and multy plug on other. Switchable output 1.5 to 12v output should be plenty big enough for the radio.

 

[pappaecho]

If you go to Rs you can buy Traco stabilised power chips with a variable 18-12 volt input, and a stabilised output of varying voltages including 6 volts. I use then in cars to step down 12 volts to provide power for mobile phones, GPS, MP3 players etc without the need for huge great 12 volt cigar lighter type plugs, of which three would be needed for the above electrical gadgets

 

[rob2]

You should be able to get a DC/DC adaptor from the likes of Maplin they come with a selection of plugs to go in the DC input socket of the equipment you're powering.

 

[Dave_Rolfe]

Thanks everyone. It looks like Maplins is my best bet. Fortunately they have just opened a branch here in Exeter.

Thanks again.

Dave

 

[VicS]

[ QUOTE ]
It looks like Maplins is my best bet. Fortunately they have just opened a branch here in Exeter.

[/ QUOTE ] Maplins is only ever as far away as your computer.


If you are actually going to a store I think you can check the stores stock on line.