Batteries To Wall

[Dark Painter]

hey guys, so ive got a project.

taking a crappy baby swing on batteries and converting
it to something less expensive hopefully.

its got 4 C's and 2 AA's, i just dont wanna cook the kid so
i'd like some advice first.

thanks

[EDIT]
**broken link removed**
google search was unsuccessful.
thanks for the help. hope someone can open me up for posting, i dont want
to edit my first post forever.

 

[dknguyen]

HOw does a swing run on so few batteries? DO you have a photo of the swing? And more importantly, where the batteries fit into?

 

[Dark Painter]

haha thanks dknguyen. i found an ebay listing since a google search was unsuccessful.

**broken link removed**

to my understanding the 4 C's must power the motor,
im sure the AA's are for the buttons, music player,
and lights. 'just want to get them off battery power and onto
house current. thanks again for the help!

 

[duffy]

I'm guessing the C cells run the motor and the AA's run the music and lights. Probably split the dang 6V supply to a +/-3V to save the cost of a couple of drivers, too. Crappy Chinese design, I am painfully familiar with them.

Open 'er up and see if this is the situation.

 

[Dark Painter]

i believe youre correct duffy. i just need to make this thing run
on wall current. no more batteries. any ideas?

 

[dknguyen]

Make a cylinder thing shaped like a battery where a wall wart output plugs into it and splits the the + and GND to each end.

 

[Dark Painter]

im used to working with two wire stuff,
like adding the electronics to cars.

maybe you could spell this out some more dknguyen?

 

[dknguyen]

Make a battery space holder with a wall-wart output plug in in the middle so you can stick it into the battery slot and plug a wall power supply into it.

Or maybe it's just easier to split the wires from the output of a wall-wart and solder them directly onto the each battery contact in the chair so then the chair becomes a plug in chair.

 

[Dark Painter]

dknguyen, the plug-in chair is what ive been trying to accomplish

i just want to know how to do that properly so i can be confident
that the chair wont go up in flames after some one walks away from it.
it will probably be on constantly, and occasionally w/o supervision.

like i said, i dont wanna cook the baby

 

[duffy]

"The" wallwart? He's going to need at least TWO if it's wired the way I suspect it is, possibly three. To do it off one he's going to need a rail splitter and some other junk.

 

[Dark Painter]

nothing new? youre right duffy thats exactly what i thought.
im pretty sure ill need two, and i can do the two wire hook up and all that,
i just need to know what to do to make sure the wall current
is regulated down to whatever each battery tray requires.

thats the only thing i need help understanding. all help appreciated =)

 

[dknguyen]

Just pick a wall-wart that has the same DC voltage as the battery you have...1.5V x however many batteries go into that tray.

If the thing is picky about it, it will have a regulator inside to do the job more (batteries aren't clean power either).

And it's a wall-wart, so it's transformer isolated. So you don't have much to worry about as long as you don't open up the wall-wart.

 

[Dark Painter]

so the one for 4 AA's would be.... 6.0?

how about the C's? those cant be the same... o.0

 

[dknguyen]

Same thing. THe larger cells just have a higher current capability and higher storage capacity.

THe voltage of a single cell is determined by the chemistry. THe only way to get more voltage from that chemistry is to put cells in parallel. A bunch of cells in series makes a battery...you know, like a laser battery or a battery of missiles.

A 9V alkaline battery is achieved by stacking 6 cells, and if you open one up it will fall apart into 6 little cells.

 

[Dark Painter]

hah wierd. i never opened them cause i thought they
might hiss if they were packed with pressure. i dont know.

so using the speaker wall wart as a template it says:

input: 120V AC 60Hz 95mA

output: 12V DC 500mA


assuming i understand, the two plugs i need to splice to the battery
pack outputs in the chair are:

AA Battery Pack (2 AA's)

input: (? same since its house current ?)

output: 3V DC? & how many mA?


C Battery Pack (4 C's)

input: (again ??)

output: 6V DC? & the mA question again...

if its as easy as this, all i have to do is find the right 3V and 6V wall warts.
right?

 

[duffy]

Probably. You may need a big capacitor - in a device like that, a peak draw that wouldn't bother the batteries may load down a wallwart. Get a transformer that puts out 6V at 1 amp or more and just jumper it in there and try it.

A larger issue is whether they split that 6v supply. See if there is a wire connected to the contacts (if any) between the second and third battery. If not, you are good to go on 6v.

Have you tried running the swing without the AA batteries? There's a good chance the swing will still work, it's just the lights and sounds that will be missing. That will tell us a little more about how it's wired.

 

[Dark Painter]

oh duffy youre absolutely right.

the 3v 80mA DC wallwart worked fine for the two AA's.

and the C's are wired the same as the doubles im pretty sure.
just requires more disassembly that i cant do right now.
the baby needs it until i get the wall wart, then i can pillage
and plunder and dismantle all i want.


thanks for your help guys. the one for the AA's worked fine.
now i just gotta do the C's.

what were you saying about 1 amp for the C's? howcome?
and how would i get a transformer or a jumper and work those into
my newfound knowledge of wall wart modification lol.

 

[duffy]

It's a guess based on battery life expectancy, consumer expectations and C cells. I doubt the average draw will even be 1 amp - it's the peak draw that may be a problem, but that can be fixed with a capacitor. Question is: will it run on 6V, or does it really need +/- 3V?

 

[Dark Painter]

when i broke open the AA battery assembly it had four prongs.

two were blank with no wires leading from them and the other two
had 1 wire each,a red and black.

lets pretend this example is my AA batt assembly.

+ (pos) --[______] <-- prong empty | blank | no wires
[ ]
- (neg) --[______] <--prong empty | blank | no wires


i doubt the 4 C cell batts are wired any differently, but if it will
really help i can crack the ****** open and see for sure.

im just not sure what the diff between a 6v and two different -/+ 3V
wall warts would be. wouldnt it be possible to wire it like the AA hookup?

unless your saying that its possible two batts could be wired together,
leaving the remaining two C cell batts to be wired up the same way.
as if we were working with the two AA's all over again, just in C cell.

regardless it would be a big help to lay out each of these possible applications. you are both awesome Duffy and dknguyen.

i'll post pics when its done just so yall can see watta big help ya been

 

[duffy]

The AA's don't tell us anything about the 6V supply. Yes, two 3V transformers would do it, if it's necessary.

Have you got a 4 C cell battery holder? You could just hook them up externally so it doesn't have that center contact and see if it still works.