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[Pragmatist]

Hi all,


Being a not too great modeler I am slightly stuck with the best way around this. I have a radar running on 2 double A batteries and a flashing light on a 9v battery. The whole thing looks a mess as I have a connector for my 9v with a switch and also a switch box which contains the 2 double A batteries. All works great but looks a mess and takes up a lot of room. Wondering if the red and black of both light and radar can somehow be spliced into one so i can have both running on one switch but not sure if 9v would run both. Putting the wires into the hull is not an option on this build.

[Stan]

Reading your post you have 3 volts running the radar and 9 volts running the L E D. Surely connecting the radar to 9 volts will see a huge increase in the speed of the radar. If you have a spare channel on your radio you could use a Action twin switch could you fit this in the hull and and use a flying lead to connect the two functions. The twin switch will allow both voltage to be used it will also allow each function to be turned on/off separately hope this helps.


Stan. [size=78%] [/size]

[malcolmfrary]

Double pole switch.  Connecting two batteries of different voltage is not an option, either.  The lower voltage battery drains the higher very quickly, at some intermediate point the radar rotates at warp speed and the lamp doesn't.
One switch, run both off the 9 volt battery and use an adjustable voltage regulator for the motor would allow one single pole switch.
Or, to run both off the 3 volt supply, a step-up DC-DC converters.  They tend to need more space than a 9v battery, but then, its not a perfect world.

[john44]

Hi reading your post you didn’t say if  you wanted the light and radar switched independently.
If not you could use a Y lead 1 leg to the 9v battery, 2 nd leg to the 9v led, 3rd leg to a component
shop voltage reduction unit which are very small, then to the radar motor.
If you do choose this method turn the VR TO MINIMUM before switching on.
Once powered up turn the VR adjustment screw to achieve the required radar speed.
Hope this helps.


John

[roycv]

You could have a common negative connection and a switch on the plus side for 3volts to the radar and another switch on the plus (red) side for the 9 volt flashing light. 

This should reduce the wiring to 2 wires out to switches from the 2 batteries and a common black negative return to both batteries.
Not drawn it out but it should work.  It could be that with a metal mast if isolated, this could be the common negative return.

You only need miniature switches for the job as the voltages and current are very low.

Roy

[Plastic - RIP]

I would dump all the other batteries - just fit a couple of DC-DC converters in the hull driven from the main battery and have a lead from the superstructure to plug in - something like a 3.5mm stereo jack would be ideal as you can buy the lead and the converters from ebay for pennies.   Mount the socket in the hull so you can just unplug for maintenance.


If you want something really fancy, some converters have an led display for output voltage.         https://www.ebay.co.uk/itm/152805595170?hash=item2393ec5822:g:se0AAOSwsFpaHNoh 

[roycv]

Hi plastic glad you are still with us.  Do not agree with your thoughts however!  First buying votage converters increases the number of parts in the system. 

I also urge people NOT to connect a DC connection using the plug as suggested.  Everytime you pull the plug out ot put it in there is a momentary short circuit.
I did this myself many years ago in a not disimilar way with a rechargeable battery and you get quite a big flash!
Good luck
Roy

[Plastic - RIP]

Hi Roy - I'm still here!     I start my 9th chemo on Friday.   

The DC converters vastly simplify the whole installation - in my opinion - all neat & tidy in the hull with short wires.   

The 3.5mm connector would be on the down-side of the DC converters - low power only - any short would be handled by the foldback protection system in the converter - you could stick a screwdriver in the socket and nothing would even get warm.     

It's way safer than mucking about with connecting to a battery.    If you were really panicky, you could always bung a fuse between the main battery and the converters - but they are a perfect way of supplying safe, low-voltage power.

[roycv]

Hi james nice to know you are still around and still kicking!  I use a DC converter myself, the expensive one from Component shop with meter reading, got change from £4.  Still a lot of fuss for a flashing light and a radar.
All the best
Roy

[Plastic - RIP]

Hi james nice to know you are still around and still kicking!  I use a DC converter myself, the expensive one from Component shop with meter reading, got change from £4.  Still a lot of fuss for a flashing light and a radar.
All the best
Roy

I'm managing to get out and about - got to jump around in some DH Mosquito cockpits recently.   
The converters are a one-time fit and forget - less wires, short-circuit protection, variable voltage, no messing around with in-and-out of extra batteries and risking damage to the superstructure and it lowers the centre of mass - I'm having difficulty thinking of any downside.   

[roycv]

I can see where it all comes from James!  You never give up!!!!
Keep going mate, I will probably still argue with you though!
Roy