Getting 6 volts from 12.

[doug748]

This is for my man shed but it could be of use on a boat.

I have some Infra red triggered alarms and lights that are powered by 4 AA cells so a nominal 6v. To save on batteries I would like to run them from a car battery.

There are one or two suggestions for circuits on't web, can anyone point to an off the shelf fix?


Would this make a YAPP - or is it too easy?

 

[lw395]

Loads of pre-built modules on ebay
search for 'step down'

http://www.ebay.co.uk/itm/Ultra-Sma...177?pt=LH_DefaultDomain_3&hash=item2c97836ea1

 

[alahol2]

I've just used a few of these to provide 11V to LED strip lights on the boat. Easy connection and voltage adjustment, seem to do what they say so far.
http://www.ebay.co.uk/itm/151311737680

 

[doug748]

Thanks for that, easy when you know what to look for.

 

[Alpha22]

2 sixes is 12 so run them in pairs in series........ or is that too simple?

 

[William_H]

2 sixes is 12 so run them in pairs in series........ or is that too simple?

No don't try to run them in series. They draw a comparitively lot of current when triggered and not much while waiting. So if one triggers and the other does not you will get almost all the volt drop across the non trigered one. However if you put NiMH rechargeable batteries in each light then you could charge them in series from 12v. Fit a series resistor to limit charge current to quite small for 24/7 charging. I do something similar using a tiny 6v solar panel.
Regulators come in 2 types. The typical regulator chip 7806 has a transsitor which varies in resistance to produce the 6v but wastes as much power in heat as the device draws.
The switch mode type are more efficient but more complex and can give radio interference. The type in the link is a switch mode type.
A cheap sopurce (you may even have one) is the USB port type for cars. 12v in 5v out. I am sure 5v will be enough.Difficulty there is connecting to the USB port and the 12v plug. good lck olewill

 

[elton]

2 sixes is 12 so run them in pairs in series........ or is that too simple?

It's funny how a little bit of knowledge goes ........ absolutely nowhere.

Yes, it's too simple, and it won't work.