External battery, will this work?

[Bravo25]

This is an idea I came up with for the Sams HID, I wanted an external battery pack for longer run time, and to be able to charge it via the on board circuitry. Can anyone tell if this will work?

Thanks

 

[Bravo25]

Anybody got an opinion on this?:candle:

 

[rdh226]

Your diode breaks everything. *OK, not everything, but...

Depending on its orientation, you will either never be able to use the onboard
battery, nor correctly charge it
(or will overcharge the outboard battery if the onboard charger is set 0.6V high)
--or--
you will discharge the onboard battery and never be able to charge it.

The diode limits current to one direction. It further accounts for a 0.6V (nominal) voltage drop across the diode.

You want to parallel the batteries plus-terminal to plus-terminal and minus-terminal to minus-terminal, direct.

You also want "identical" (as near as practical) batteries, obviously technology (SLA vs NiMH vs LiIon), but also
rated capacity. Don't parallel a 3AH internal battery with a 120AH external battery and expect good charge results.

-RDH

 

[Bravo25]

They are the same battery. I thought charging would occur through the negative side(but admittedly don't know which is why i am asking). If there is not a way to direct current flow, wouldn't the external battery discharge faster because it is just dumping into the internal one?

 

[Norm]

Don't forget you will drop .6 of a Volt through the diode (assuming it is silicon).
Norm

 

[yellow]

if You are able to insert the connections and the diode, it should also be possible to somehow completely switch between internal or external batt.
:thinking:

 

[Daekar]

if You are able to insert the connections and the diode, it should also be possible to somehow completely switch between internal or external batt.
:thinking:

That's what I was thinking. If you're looking for a good external battery that would fit in a backpack and leave plenty of room for other goodies, you might want to try one of these. They're 13mmx230mmx300mm in size, 120-130Wh... They'll require a little adapting, but should be light and powerful. The only thing you might need to worry about is the correct output voltage...

 

[Bravo25]

Anybody know where to get a barrel plug, and jack that disconnects a circuit? Kind of like a headphone plug, and jack. I think that would solve my problem. When the external was plugged in it would disconnect the internal. Conversally when it was plugged in the onbaord charger would charge it. When unplugged it would bridge the connection to the internal, and charge, or run of from it.