Battery charging contact ideas for H/H device

[Andy]

Hello,

I am working on a hand held device containing a rechargeable battery.
When not in use, the device will be placed in a charging cradle /
holder. Charging current is only a few tens of milliamps. I am looking
for a few ideas on how to make the spring loaded connections between
the cradle and the device. I have searched through quite a few
catalogues but have not seen anything suitable as yet.

Maybe someone has overcome this previously and would care to share
their experiences with me? I am open to all ideas.

Andy

 

[David L. Jones]

Hello,

I am working on a hand held device containing a rechargeable battery.
When not in use, the device will be placed in a charging cradle /
holder. Charging current is only a few tens of milliamps. I am looking
for a few ideas on how to make the spring loaded connections between
the cradle and the device. I have searched through quite a few
catalogues but have not seen anything suitable as yet.

Maybe someone has overcome this previously and would care to share
their experiences with me? I am open to all ideas.

Andy

Maybe something like the "Pogo" pins used on PCB bed-of-nails testers?
Farnell have them.
How about an induction coil that doesn't need contacts?
Is this for production volume?

A cheap and somewhat crude solution would be two banana plugs sticking
up out of the charger box which mates with recessed or low profile
banana sockets on the device. That will hold the device securely up in
the air too, no "cradle" required. Some force required to sit it down,
but serves a dual purpose.
Using 2mm banana plugs will save space too.

Dave

 

[Mike]

Maybe someone has overcome this previously and would care to share
their experiences with me? I am open to all ideas.

If you are only looking for a really small current, then why not
just ordinary induction, no need for any exposed pins, you dont
even need a moulded cradle, just sit the h/h device on a pad and
let magentism do the rest ?


--
Regards
Mike
* GMC/VL Commodore, Calais VL Turbo FuseRail that wont warp or melt !
* High grade milspec ignition driver electronics now in development
* Twin Tyres to suit most sedans, trikes and motorcycle sidecars
http://niche.iinet.net.au

 

[Andy]

Maybe something like the "Pogo" pins used on PCB bed-of-nails testers?
Farnell have them.
How about an induction coil that doesn't need contacts?
Is this for production volume?

A cheap and somewhat crude solution would be two banana plugs sticking
up out of the charger box which mates with recessed or low profile
banana sockets on the device. That will hold the device securely up in
the air too, no "cradle" required. Some force required to sit it down,
but serves a dual purpose.
Using 2mm banana plugs will save space too.

Dave

Hello Dave and group,

Thanks for the replies so far. I forgot to mention the source for the
charger will be DC only (from a vehicle). This may complicate the
induction idea somewhat. I haven't looked into this fully but maybe
there are dedicated devices to achieve this without too much extra
engineering?

At this stage only looking at low volumes. I will investigate the 2mm
banana plug idea.

Thanks,

Andy

 

[Mike]

Thanks for the replies so far. I forgot to mention the source for the
charger will be DC only (from a vehicle). This may complicate the
induction idea somewhat. I haven't looked into this fully but maybe
there are dedicated devices to achieve this without too much extra
engineering?

One transistor oscillator and coil - little mtp3055 would be ideal
and transmit more than enough power, dont even need a core, air is
fine, full bridge in receiver with resistor and a zener would prob
suffice.

At this stage only looking at low volumes. I will investigate the 2mm
banana plug idea.

Think big,

<chuckle>

--
Regards
Mike
* GMC/VL Commodore, Calais VL Turbo FuseRail that wont warp or melt !
* High grade milspec ignition driver electronics now in development
* Twin Tyres to suit most sedans, trikes and motorcycle sidecars
http://niche.iinet.net.au

 

[rob]

Hello,

I am working on a hand held device containing a rechargeable battery.
When not in use, the device will be placed in a charging cradle /
holder. Charging current is only a few tens of milliamps. I am looking
for a few ideas on how to make the spring loaded connections between
the cradle and the device. I have searched through quite a few
catalogues but have not seen anything suitable as yet.

Maybe someone has overcome this previously and would care to share
their experiences with me? I am open to all ideas.

Andy

Does it need a cradle - can it possibly be mounted directly into the cig.
lighter? Like the removable / low cost hands-free phone jobbies.

 

[Dac]

The best way is to check out cordless phones.

Basically the base as two horizontal bars that can be depressed down, and
the phone has two horizontal bars sticking out of it perpedicular.

 

[John G]

Hello Dave and group,

Thanks for the replies so far. I forgot to mention the source for the
charger will be DC only (from a vehicle). This may complicate the
induction idea somewhat. I haven't looked into this fully but maybe
there are dedicated devices to achieve this without too much extra
engineering?

At this stage only looking at low volumes. I will investigate the 2mm
banana plug idea.

Thanks,

Andy

You could try looking at some of the bistro food places that have radio
pagers for when you food is ready.
They seem to be quite innovative.
Just stack the pagers in a cradle and they charge up thru the lower
ones.
They seem to be custom made so that may be a problem.
There are several variations and you could try the food at the same
time.

 

[VV4yn0]

Rare earth magnets could provide both the contact and the cradle/attachment
Alternatively, could you get a solar cell in there?
Wayne