Need a custom battery rig for project--Will pay!! $$

MikeGoob

Newly Enlightened
Joined
Jan 19, 2009
Messages
23
Trying to get a series of cells to power a decorative project. Think low output, extended life.
I know numbers needed but don't get Cell Chemistry or all the nuances that goes into it. I need an expert!

Please help--will pay!
Thanks guys!
 

MikeGoob

Newly Enlightened
Joined
Jan 19, 2009
Messages
23
This is to power a series of small LED diodes. Output 12v 3amps or 5amps, 8 hour life.
Im imagining a series of cells end to end, can be 2" diameter, 24" long, this is for a light project, not a handheld light. Something stable that can run for 8 hours, charge in 5-8 hours.
 

bbawkon

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May 20, 2011
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73
12V * 3 Amps = 36Watts, 36 Watts * 8 Hours = 288 Watt Hours Add 20% for Efficiency Losses = 345.6 Watt Hours.

If you do 3.7V Cells, You'll Need a total of 93 Amp Hours (93,000 mAH) of batteries. An 18650 is roughly 2400 mAH (on a REALLY REALLY good day), so if you were to use those, you would need about 40 of them).

For 5 Amps, it's worse.. 155 Amp Hours or about 65 18650 Lithium Cells.

This all assumes a switching power supply with 80% + efficiency.

Ben
 
Last edited:

Ken_McE

Flashlight Enthusiast
Joined
Jun 16, 2003
Messages
1,687
...If you do 3.7V Cells, You'll Need a total of 93 Amp Hours .. For 5 Amps, it's worse.. 155 Amp Hours ....

This puts him into the region of car batteries. MikeGoob, can you run a line to a couple of car batteries sitting off to the side somewhere?
 
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