Small Hobby project :)

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So I have a small project on hand. Where, I am trying to convert it to direct DC voltage, instead of using batteries.

Currently, each side is using 4 AA batteries and in total it uses 8 AA, question is, if I directly connect 12VDC input to it, would it work or no?

Any other advice or suggestions for hooking it up with direct DC voltage?

 
It was as if you went WAY out of your way to obfuscate whatever it is you're working on.

1) Whiskey Tango Foxtrot kinda machine are you talking about? I ask so the non-clairvoyant among us (like me) can get in the race.
2) Are both 4-cell battery packs wired in series (creating an 8 cell power source)?
2a)....or are the 2 4-cell battery packs powering 2 different things?
3) I have an adjustable DC source which I use all the time to test and power battery powered things. It works every time I employ it.
ERGO I would think IF your system requires voltage from 8 AA batteries (12V) your power source set at 12 (not 6) will work just fine.

FREE GUESS (because I'm a good person) Is this a Roomba?
 
He he he Lol
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It's actually a trash can, electrically and motion operated, which takes batteries and trying to convert it to DCV, so that no more batteries
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So you want to run your battery powered trash can on 12v wired DC? A AC->DC converter seems like the answer?
 
Originally Posted By: Reddy45
So you want to run your battery powered trash can on 12v wired DC? A AC->DC converter seems like the answer?


Yeah, I do have a few converters, from AC to DC.

So I can use both of them, it seems to be both of these 6 V are connected to each other in parallel.
 
I did the same sort of thing with a Giant Ikea clock that liked to eat batteries. I used a 5 volt power supply with a step-down board to get the voltage to about 1.5 volts.

If your device is using something standard like 12, 6, 9, volts then it should be easy to achieve what you want. The key is figuring out how may volts your device requires. Put the batteries in it and then with a Multi-Meter set to DC try connecting to one positive pin where a wire lead is and another on the opposite supply and keep doing the different combinations until you find the highest voltage.

This will be the supply voltage you need. I can't see you needing anything over 1/2 an amp (500ma) at whatever voltage you need because it's battery powered.
 
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You may need to determine if it's just a motor in the trash can or a circuit board board also. You may need to provide a clean 12V DC.
 
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Originally Posted By: maverickfhs
it seems to be both of these 6 V are connected to each other in parallel.


If that is the case, then you need a 6VDC supply.
 
Right, so it's using 4 batteries of 1.5V on each side, I measured using a voltmeter and each side is using 6V and then both are seemingly connected in parallel(maybe?)

It has a switch also, to turn it on and off, does have a motor and a circuit board too. I'll share a pict shortly.
 
Like other have said, just confirm what voltage the circuit board is seeing from the batteries (12V or 6V) and replace it with an appropriate wall wart power supply.

If you want to get a little fancy, get a panel mount barrel jack, ideally a 3 pin model with a built in switch. Drill a hole, wire the batteries through the switched input, then to the circuit board. That way if you disconnect the barrel plug, it'll automatically switch to battery power. If you want to get fancier, replace the AA batteries with rechargeable Lithium-Ion batteries, install the same barrel plug, and connect the DC input to a lithium-ion charge circuit.

Sample barrel jack (get one that fits the adapters you have)
https://www.digikey.com/product-detail/e...7hoCFZgQAvD_BwE

Or just use rechargeable batteries.
 
Thanks guys, how can I check voltage across circuit? There are a few pictures below, one is for circuit board, motor, then area where 4 batteries are going on each side and a on-off switch.

If I measure across each side of batteries, it's showing 6V on left, as well as right. Does it mean whole unit is using 6 Volts or 12? Another thing, if I take out onside 4 AA batteries, lid still operates, which makes me believe it's utilizing 6V alone. Does current matter in this situation or no?

Thanks for the help.







 
Originally Posted By: maverickfhs
If I measure across each side of batteries, it's showing 6V on left, as well as right. Does it mean whole unit is using 6 Volts or 12? Another thing, if I take out onside 4 AA batteries, lid still operates, which makes me believe it's utilizing 6V alone. Does current matter in this situation or no!

Sounds like it's a 6 volt system. Sure way to check is measure the voltage across the motor while it's running.

If it is a 6 volt system, then the 2 banks of 6 volt modules exist because of the current draw which could be pretty high if it eats up 8 batteries pretty fast.

If you have a clamp on DC amp meter, should try to get a current draw measurement while running with both battery banks installed with new-ish batteries.

Your AC to DC power source will have to be able to supply enough current too, so should measure it to verify required current.
 
Originally Posted By: maverickfhs
Right, so it's using 4 batteries of 1.5V on each side, I measured using a voltmeter and each side is using 6V and then both are seemingly connected in parallel(maybe?)

It has a switch also, to turn it on and off, does have a motor and a circuit board too. I'll share a pict shortly.


What is the polarity? By that I mean is it 2 separate +6V supplies or is it +/- 6VDC?

In a +/- supply, you will get +6V / 0V / -6V on three legs. The middle leg will be tied to ground.

IF they are connected in parallel, you will have two legs, one 0V and one +6V.

IF they are connected in series, you can have the +/- supply of 6VDC (on three legs) or you could have +12VDC (on two legs).
 
From your bottom photo it looks like they are connected in parallel, with a 0V / +6V supply. This is done to increase the current capacity of the battery powered device. That the lid operates but not the motor seems to support this ... the device requires more current than a single bank can provide to fully operate.

However you should confirm this with a DMM ... be sure the + lead of bank 1 is connected to the + lead of bank 2.

IF they are connected in parallel, now your problem is to discover (calculate) the current requirements, and then seek out a +6V wall wart with the appropriate current rating (in mA [miliamps] or A [amps]). If you have trouble sourcing something exactly correct, it's OK to use a replacement supply rated higher than you need but not lower.

Estimate 2000 mAH per 1.5V cell, so 8AH per 6V bank, total 16AH @ 6V.

With a 6V supply that translates to about 2.67A capacity, so that's the size of wall wart you should seek. It will probably work with a smaller capacity wart but you don't know how much smaller (as it eats batteries) so don't cheat too much there.

You are also going to have to do some soldering, one way or another, so hopefully your skills are up to the task and you have a decent iron. Ordinary 60:40 or Eutetic 63/37 tin/lead solder is fine. Lead Free requires higher temperatures and is easier to damage components with, but if you expect to be exporting your device to Holland or Germany, by all means use EU-legal lead free.
 
I am going to check current too. In terms of polarity for left side, there's one + and -, then for other side similarly there's one - and +.

As I said, lid still operates fully if there's only 1 single bank is present. Tested after removing other one, motor at the lid is consuming ~4V.

Also yes, + one bank is connected with + of other and similarly - of one with the other -.
 
Originally Posted By: Johnny2Bad
From your bottom photo it looks like they are connected in parallel, with a 0V / +6V supply. This is done to increase the current capacity of the battery powered device. That the lid operates but not the motor seems to support this ... the device requires more current than a single bank can provide to fully operate.

However you should confirm this with a DMM ... be sure the + lead of bank 1 is connected to the + lead of bank 2.

IF they are connected in parallel, now your problem is to discover (calculate) the current requirements, and then seek out a +6V wall wart with the appropriate current rating (in mA [miliamps] or A [amps]). If you have trouble sourcing something exactly correct, it's OK to use a replacement supply rated higher than you need but not lower.

Estimate 2000 mAH per 1.5V cell, so 8AH per 6V bank, total 16AH @ 6V.

With a 6V supply that translates to about 2.67A capacity, so that's the size of wall wart you should seek. It will probably work with a smaller capacity wart but you don't know how much smaller (as it eats batteries) so don't cheat too much there.

You are also going to have to do some soldering, one way or another, so hopefully your skills are up to the task and you have a decent iron. Ordinary 60:40 or Eutetic 63/37 tin/lead solder is fine. Lead Free requires higher temperatures and is easier to damage components with, but if you expect to be exporting your device to Holland or Germany, by all means use EU-legal lead free.


Thanks for your valuable input and advice
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Originally Posted By: bcossa2001
New topic for me. I have an indoor/outdoor thermometer/clock that eats batteries. How did you connect the power supply,to your clock?


I made a fake battery out of a cardboard cylinder and put wires on either end. I fed this to a adjustable voltage step down board I got off E-Bay for $2 and then to a 5 volt DC power supply. Works great. Been 5 years.

If you want pictures or links send me a PM.
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