18v drill battery to 5v regulator?

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Coxyboy
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18v drill battery to 5v regulator??

Hi I have been doing a bit of research but am still a little unsure,
I am trying to charge an iPhone from a dewalt drill battery,

What I have so far is that the iPhone is a 5v 1000ma supply
And the dewalt battery is 18v lithium ion

Can I use a 7805 regulator or will I have to use a 7812 regulator first?
Also what heat sinks etc would I need

Thanks for any help
Sorry not up on the electronics ! Ha
 
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Coxyboy said:
Hi I have been doing a bit of research but am still a little unsure,
I am trying to charge an iPhone from a dewalt drill battery,

What I have so far is that the iPhone is a 5v 1000ma supply
And the dewalt battery is 18v lithium ion

Can I use a 7805 regulator or will I have to use a 7812 regulator first?
Also what heat sinks etc would I need

Thanks for any help
Sorry not up on the electronics ! Ha

It would be much more efficient (the Dewalt battery will last longer, and you won't need heat sinks) if you use a switching DC-DC buck regulator to convert from 12V to 5V. You may be able to find a pre-built one, or there may be simple electronics kits that you could solder together to do this...
 
This regulates the voltage - USB Charger

Any choice of these is the power supply, ensure it is rated at 7.4v or 2s (3.7*2) - Batteries

These are the proper plugs for the battery(s), "female" are for the batteries - Plugs/adapters

Chargers can be had on the cheap too, most are offered without a power supply themselves - Cheap wall charger good for 3000mah (about a 5 hour charging time)

probably total $40-50 incl shipment to an open trade area for a 3000mah power supply for usb charging...not bad at all. Oh but requires mere guerrilla precision soldering skills.
 
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Coxyboy said:
Will something like this do?
http://item.mobileweb.ebay.com/viewitem?itemId=251276533029&cmd=VIDESC
How will I get a consistent 5v supply out and it has a vout range above and below?

I don't see a datasheet at that page (I may have missed it), so it's not clear how to set the output voltage. I'd stick with a fixed version, like the one I posted. Because cars use 12V batteries, 12V to 5V step-down converters are pretty common.
 
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berkeman said:
I don't see a datasheet at that page (I may have missed it), so it's not clear how to set the output voltage. I'd stick with a fixed version, like the one I posted. Because cars use 12V batteries, 12V to 5V step-down converters are pretty common.

Will this be suitable ?

http://uk.rs-online.com/mobile/p/switching-regulators/6664379/

As I am In The uk I have been checking local sites will I need anything else?
Sorry for the questions
Thank you in advance
 
Last edited by a moderator:
berkeman said:
That looks like a reasonable candidate. Check the datasheet to see if you need to add external capacitors --they may be included inside though.

http://www.tracopower.com/products/tsr1.pdf

According to the data sheet an input capacitor is only needed when input is greater than 32v so hopefully this will be all I need I will order it and let you know how I get on thanks
 

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