[sdiy] Combined Battery Charger / Power Supply Kit?

[Michael Zacherl.]

Hi All,

   I'm conceiving a portable synth +  fx-box which I'd like to also have battery powered.

My idea is to have 4 rechargeable 9V NiMH blocks to get +/- 15V from the charger/supply unit.
I have no experience with such circuits and charging batteries hence I'm looking for a kit or pcb.

I want to have it this way since charging 9V batteries usually  means to have 2 to 4 chargers,
Even my big Ansmann Energy8 provides only 2 slots for 9V batteries.
And once it works it's much more convenient.

Basically it should be like in notebooks (this synth will be a laptop too ;-) : 
Wall-wart connected, the device is being supplied and the batteries are charging.
Wall-wart disconnected runs the box from the 9V blocks.
The circuit also should work as a PSU when no batteries are inserted and for backup it should 
be able to deal with Alkaline cells (w/ no charging of course) as well.
An optional switch to prevent charging and an accurate status LED would be nice.

I'm also looking at NiMH and Li-Ion battery packs but I'm not sure if I want to go for something proprietary.
(and adding Alkalines wouldn't be possible as well).

Since I'm located in Austria an EU based vendor would be nice.
(but I prefer quality over shipping charges and custom fees ;-)

This is an rough idea and I'm still collecting thoughts, nothing's carved in stone.

Any hints, pointers?

Thanks a lot, Michael.


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