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ASAP!!! Converting an 120v AC charger to run off 12v? Answered

Basically, I have a camera battery charger that runs off of 120v AC. On the charger it says it outputs 8.4v at .43 amps. I have a solar panel that does 12v at 300ma (or 6v at >1A). Could I take the charger, and wire it into the solar panel? I know the output of the panel at 12v is less than the charger, but it might be able to charge. Has anybody done anything along the lines of this? I would be really happy if I could charge my camera batteries from the sun, as I am going on a trip soon, and they don't have a great power system :)
The batteries are LI-Ion, so they DO need a charger...

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icengBest Answer (author)2012-02-15

If the charger can be popped open ( ie not solid encapsulated )
Just insert your solar panel after or before the rectifier that feeds
the regulating guts used to charge your Lion.

A

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iceng (author)iceng2012-02-15

Hey, the fourth ible on the right of this page
shows how to hack into a lion charger ======>>>>>>>>>

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astroboy907 (author)iceng2012-02-15

hmm- makes me wonder- do the batteries contain a charge regulator, or the power supply? I know the battery should have a discharge regulator, but I wonder if it has a charge circuit... It has 4 pins, V+, D, T, and GND (in that order)... Do the D & T mean anything? Also- it says to charge with specified charger only--- if that makes a difference. Thanks for the answers..

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iceng (author)astroboy9072012-02-15
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astroboy907 (author)iceng2012-02-16

Charger is encapsulated.... Not going to go through with tearing it apart... I see some knock off 12v chargers on ebay :)

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Re-design (author)2012-02-15

NO! Unless your charger has an input for 12 volts. Some do so they can be used in an auto.

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astroboy907 (author)Re-design2012-02-15

could you explain (scientifically) why not? logically I would be able to tie in after the voltage converter, and source an 8.4v line into it..

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Re-design (author)astroboy9072012-02-15

Sorry. I didn't realize you were willing to go to the trouble of reverse engineering to power up the charger. I (wrongly) assumed that you were looking for and easy fix.

There is certainly no reason why you very probably could open up the box and locate the correct points to add the solar power cell to your charger.  There is a chance that in weak lighting your charger will be underpowered and the protection circuits might not work properly though, a bad scenario when charging li-ion batteries.

In the end you might end up with a portable charger or just a paper weight.

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astroboy907 (author)Re-design2012-02-16

Shoot- the charger is encapsulated, so I might as well buy a knock off 12v one (I dont want to go through all the dremeling as of yet). Thanks for the tips :)

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lemonie (author)2012-02-15

If you could isolate the low-voltage charger from the transformer & LV power-supply, it'd probably hook-up to 12V OK.

L

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Kiteman (author)2012-02-15

There are pages and pages of solar charger projects here

Something there should hold the answers you seek.

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