### Author Topic: Battery Circuitry  (Read 2269 times)

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##### Battery Circuitry
« on: December 26, 2014, 12:58:57 am »
Hi All
I hope I am right posting here.
I am more of a Digital Guy with next to no experience in analog Stuff…  Thus I need help?
To run my circuit I need 18V to 21V with an average current of 3A as well as 5V at 1A out of a Battery. (It would be best if I could choose Start Voltage and cut out Voltage) Due to the weight capacity ratio and the safety aspect I thought of using a LiFe battery. I don´t need to integrate some kind of Charging circuit (Battery will be Charged with a dedicated Charger).
I have done Research but nothing turned out. Besides I don’t want the Battery to blow up in my Face due to my Stupidity.
If someone could help me I would be very thankful!
All the best and a Happy New Year

#### mikerj

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##### Re: Battery Circuitry
« Reply #1 on: December 27, 2014, 07:11:14 pm »
You missed out an important bit of information; what is the battery voltage?

#### Richard Crowley

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##### Re: Battery Circuitry
« Reply #2 on: December 27, 2014, 07:30:20 pm »
Please provide a URL to the specifications of the battery you are asking about. Most (all?) of us don't know what you are talking about.
I found something called "LiFeSource" (lithium-ion) batteries. http://www.lifesourcebatteries.com/  Is that what you mean?
If these things provide only 6.6V, what was your thinking about how to get "18-21V"?  What do you need "18-21V" for anyway?

Perhaps it would be best to start over and lay out the complete game plan instead of asking us to validate your proposed solution to an undefined problem.

• Newbie
• Posts: 2
##### Re: Battery Circuitry
« Reply #3 on: January 19, 2015, 07:36:20 am »
Thank you for the Quick replies! My Computer broke and I didn't have any possibility to reply.
I am planning to use 4 LiFePo4 in Parallel. Fully charged they would supply about 12V and a Cut-off Voltage of 8V is expected.
The Circuit requires the (18-21V@3,5A and 5V@1A) it cannot be built more efficient. In my understanding I would need some king of Boot converter IC nut I have no real clue what I could use…
> I almost forgot the use? I would like to upgrade my Desk Lamp
Cheers

#### Richard Crowley

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##### Re: Battery Circuitry
« Reply #4 on: January 19, 2015, 08:27:02 am »
You STILL have not provided a reference to the battery you are asking about.
Dunno how we can properly respond without that.

Connecting batteries in parallel is a problem both in charging and supplying power to the load.

Using multiple exotic cells, connecting them in series, and using a voltage converter seem WILDLY over the top to simply power a "desk lamp".
From only the details you have provided here, this seems completely unsuitable and impractical.

#### IanB

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##### Re: Battery Circuitry
« Reply #5 on: January 19, 2015, 08:35:49 am »
I almost forgot the use? I would like to upgrade my Desk Lamp

Desk lamps don't seem like they need a supply of 18 V to 21 V at 3.5 A and a second supply of 5 V at 1 A.

You are causing a huge amount of confusion by not providing clear information.

In order to receive help, you need to post a link to the specific battery you are thinking of using, and then explain what you want to power with this battery and for how long.

The simplest answer anyone can give you right now is that what you want to do isn't going to work. If you can't explain how you think it is going to work, there is no chance of it actually working.
I'm not an EE--what am I doing here?

Smf