Convert device from Alkaline batteries to DC

In summary, it is possible to use a 9v phone charger to power a device that currently runs on 6 1.5V D batteries. However, you will need to make sure the current output of the charger is sufficient and you may need to rewire the circuit. It is important to measure the current under load before selecting a power supply, and a regulated power supply is recommended.
  • #1
ppendle
3
0
I have a device that is currently running on 6 1.5V D batteries which I have to replace every 2 months as they drain very quickly. In theory would it be possible to take (say) a phone charger that puts out 9v and connect and make a circuit drawing from current from a wall socket? Obviously some rewiring would be involved -- but does it have a chance of working?
 
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  • #2
Yes, just be sure to get the polarity right. You can buy the little connector bits at Radio Shack (or equivalent store) and solder up an adapter.
 
  • #3
How do I know how much current I need. The current application drives a small motor for a couple of seconds at a time. I am wondering if the 9V cell phone charge will provide enough current.
 
  • #4
ppendle said:
How do I know how much current I need. The current application drives a small motor for a couple of seconds at a time. I am wondering if the 9V cell phone charge will provide enough current.

You should measure it with a DVM. You'll need to figure out how to make a series connection with the batteries in order to make the measurement. There's a trick I can tell you about if you aren't able to figure out a way yourself (I have to dash to a meeting).
 
  • #5
ppendle said:
I have a device that is currently running on 6 1.5V D batteries which I have to replace every 2 months as they drain very quickly. In theory would it be possible to take (say) a phone charger that puts out 9v and connect and make a circuit drawing from current from a wall socket? Obviously some rewiring would be involved -- but does it have a chance of working?

Welcome to Physics Forums! You will find there are lots of interesting topics and discussions on this site. And as you have already found, there knowledgeable and helpful people too.

What is it that you are trying to power? (If you have brand and model, that would be useful)

Do you know if your 6 cells are in series? Another possible configuration for your batteries is, 1st set of three cells in series = 4.5V, and 2nd set of three cells in series = 4.5V, and both sets in parallel = 4.5V. With this configuration you can draw twice the current (mA-hr) from your supply, compared with a single set.
 
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  • #6
"D" batteries are capable of sourcing several amperes of current, so just make sure your DC adapter is also capable of several amperes of current, and you'll be totally fine. You should be able to solder your DC adapter wires to those leaving the (empty) battery holder and the device should operate normally. Drill a little hole in the battery cover and add a little stress relief to make it look professional.

edit: I'm assuming all six 1.5V cells are in series to deliver 9V at a maximum of ~1-2 amperes.

- Warren
 
  • #7
The batteries are in series. I have a digitial voltmeter if that is what a DVM is. But it only measures voltage not current. Is it also necessary to measure the amperage under load? I have a rather crude knowledge of electrical stuff ... but that seems to be the most sensible way to go. Then I put the measuring device in series with the batteries and then put the circuit under load.

The device that I am powering is a garbage can operated a photo-sensor. The motor raises and lowers the lid (which is only two or three ounces. The battery compartment has no specifications in it -- which is not surprising.
 
  • #8
Phone charger wouldn't supply enough current and is usually onlt about 4.5V. It really depends on how much current your device uses and how the batteries are arranged. ie parallel/series. At a guess Id say series, giving you a voltage of 9V. Buy yourself an AC adaptor capable of supplying 9V. You will also need to look at the current rating on it. Usually around 100mA, 300mA 500mA so you know what youre looking for. Sometimes they're labelled in Watts or VoltageAmps, eg 10W, 12W or 10VA 12VA etc. Guessing again and from electronic experience, I'd say you need about 500mA. so that's going to be about labelled something like 5W or 5VA. Anything higher is better. Since its your device is only operated occasionaly you will probably get away with 250mA.. Hope this helps.
 
  • #9
ppendle said:
The batteries are in series. I have a digitial voltmeter if that is what a DVM is. But it only measures voltage not current. Is it also necessary to measure the amperage under load? I have a rather crude knowledge of electrical stuff ... but that seems to be the most sensible way to go. Then I put the measuring device in series with the batteries and then put the circuit under load.

The device that I am powering is a garbage can operated a photo-sensor. The motor raises and lowers the lid (which is only two or three ounces. The battery compartment has no specifications in it -- which is not surprising.

Knowing the current under load is important to selecting a power supply.
Since your DVM does not have a current range, you can fix this by putting a small value resistor in series with the battery pack and then measuring the voltage across the resistor.
A good resistor value might be 0.1 ohms. You can buy one or make one out of some magnet wire.
Warning: The resistor can get very hot.
The current can be found by the equation E=IR.
Or you can buy a better DVM with a 10 or 20 amp range:smile:

For best results the power unit you select should be able to provide twice the current that you measure.
Unless you understand you units sensor circuit the power supply needs to be regulated.
A cheap unregulated 9v DC wall wart actually puts out a peak of about 12v which might damage the sensor (or it could work just fine).
 

1. How do I convert my device from using Alkaline batteries to DC power?

To convert your device from using Alkaline batteries to DC power, you will need a DC power supply. This can be a wall adapter or a battery pack that outputs DC power. You will also need to open your device and identify the positive and negative terminals. Then, you can connect the positive and negative wires from the DC power supply to the corresponding terminals in your device. Make sure to match the voltage and polarity of the DC power supply to your device's specifications.

2. Can I use any type of DC power supply to convert my device from Alkaline batteries?

No, you cannot use any type of DC power supply. You need to make sure that the voltage and polarity of the DC power supply match the specifications of your device. Using the wrong type of DC power supply can damage your device or cause it to malfunction.

3. What are the benefits of converting my device from Alkaline batteries to DC power?

The main benefit of converting your device from Alkaline batteries to DC power is convenience. You no longer have to constantly replace batteries and can instead use a continuous power source. This can also save you money in the long run. Additionally, DC power is typically more stable and reliable compared to batteries.

4. Are there any potential risks or drawbacks to converting my device from Alkaline batteries to DC power?

One potential risk is that if the voltage or polarity of the DC power supply is not compatible with your device, it can cause damage or malfunctions. Additionally, if the DC power supply loses power or malfunctions, your device will also lose power. This can be a concern for devices that require uninterrupted power, such as medical equipment.

5. Can I convert any device from Alkaline batteries to DC power?

In most cases, yes, you can convert any device from Alkaline batteries to DC power. However, it is important to check the specifications of your device and ensure that the voltage and polarity of the DC power supply match. Some devices, such as those with specialized battery compartments, may not be compatible with conversion to DC power.

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