Converting Device to Battery Power

Thread Starter

Caches

Joined Apr 9, 2020
18

wayneh

Joined Sep 9, 2010
16,384
You’re going to need more than a battery. I think you may need a regulator on the voltage.

It says 15V DC (16 max) and 150mA when not loaded. It doesn’t mention a minimum voltage and that’s a question mark. Any battery will lose voltage as it discharges. So if you arrange a battery pack to provide a voltage of between 15 and 16 volts when freshly charged, it will shortly fall under 15V. We don’t know what that might do. Might be fine but maybe not.

Fortunately there are options and you could even experiment a little to see how much you need a regulator. If the thing works fine on 12V, a 15V pack would be fine.
 

crutschow

Joined Mar 14, 2008
24,730
You could use a lower voltage battery with a boost converter to get a stable 15V with good efficiency.
The size and type of battery depend upon how long you want it to run before a recharge is needed.
Lithium-ion batteries have the best power to weight ratio, but are also the most expensive and the trickiest to charge.
NiMh batteries are cheaper but heavier.

For example using 10 AA NIMh's for 12V with a nominal 2Ah capacity, would give about 8 hours of operation at the no-load current of 150mA, with a typical 80% efficiency boost converter.
The total battery weight would be about 11 ounces (310 grams).

Edit: Using a 12V battery has the advantage of allowing the battery charger to use the 15V wall-wart that comes with the generator.
 
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Thread Starter

Caches

Joined Apr 9, 2020
18
I'm in way over my head here lol... This is a first time project for me. It will take a little time to piece together the right parts based on the information you guys have so kindly been willing to share. But I'm much closer to the solution than I was before I came here. So thank you very much for your help.
 

Thread Starter

Caches

Joined Apr 9, 2020
18
I have an idea to mount the generator and battery in the black enclosure along with this battery/voltage meter near the face of the generator...

https://www.ebay.com/itm/10-100V-LCD-Acid-Lead-Lithium-Battery-Capacity-Indicator-Voltage-meter-Tester/282683092681?hash=item41d139aec9:g:~iQAAOSwOKVZ1yLt

If I wanted to go all out with a lithium ion battery, can someone make a specific recommendation from Ebay? I of course wanted to be able to charge the battery from the outside without having to open up the enclosure. If I'm ever able to get this thing together and working I'll post pictures of it here. Sorry I'm such a newb. I really appreciate any help.
 

crutschow

Joined Mar 14, 2008
24,730
You'll also have to add a charger circuit specifically designed for the type and voltage of the battery you will use.

Why do you want it to be battery powered?
That's not common for bench instruments.
 

Thread Starter

Caches

Joined Apr 9, 2020
18
I will go ahead and tell you what I'm using this for. I am a treasure hunter and have come to learn how to locate specific types of buried objects using a frequency generator. The whole thing is theoretical at this point and you won't find any scientific evidence to back it up. But I've actually seen it work in the field. Here is an example of a frequency generator being marketed to treasure hunters:

http://gdi-detectors.com/rayfinder-gold-detector-long-range-locator/

As you can see these types of devices are extremely overpriced given the cost of the materials used to build them. So I wanted to piece one together myself and potentially save a couple grand.
 

crutschow

Joined Mar 14, 2008
24,730
Okay.
Well then you have to factor in how much current the search coil and its circuitry takes when determining what battery you need.
 

Thread Starter

Caches

Joined Apr 9, 2020
18
This type of device doesn't use a search coil. The idea is that you connect the frequency generator's output to two metal probes stuck in the ground. Then you walk in a circle around the FG holding two dowsing rods. If there is any buried gold or silver within range of the frequency generator, a "signal line" will form between the FG and the buried object. The FG somehow connects to the buried object when you have it set to emit the frequency which resonates with the specific element you are seeking. When you walk over the signal line, your L-rods will cross as a result of some unknown bio-reaction that takes place when your body is positioned directly above the signal line. You follow the signal line until it ends. The end of the line is the location of your buried object.
 

Thread Starter

Caches

Joined Apr 9, 2020
18
So all I need to power is the frequency generator itself. I think if I had someone point out a lithium ion battery that could power it for a good 8 hours then I would be set. If you have time to make a quick scan of the options on Ebay and supply a link it would be greatly appreciated.
 

wayneh

Joined Sep 9, 2010
16,384
Would it be practical to use removable batteries that you could charge externally? Using the boost converter to get a steady 15V, you could use something like 6-8 AA cells. Maybe using off-the-shelf stuff is a convenience?
 

Thread Starter

Caches

Joined Apr 9, 2020
18
Yes, removable batteries would be fine. If you have time to do a quick search on Ebay and give me the links to what you're talking about that'd be great. Basically whatever is easiest for a total newb to get working would be ideal. I thank you
 

wayneh

Joined Sep 9, 2010
16,384
Yes, removable batteries would be fine. If you have time to do a quick search on Ebay and give me the links to what you're talking about that'd be great. Basically whatever is easiest for a total newb to get working would be ideal. I thank you
Here's a starting point at Amazon:
https://www.amazon.com/Thicken-Battery-Holder-Switch-QTEATAK/dp/B07WY48TFC/ref=sr_1_11_sspa?dchild=1&keywords=6+aa+battery+holder&qid=1586527687

There are many, many permutations. I think you could get away with as few as 4 cells but it depends how many hours between charges you need, and how much room and weight you can devote to the battery.
 

Thread Starter

Caches

Joined Apr 9, 2020
18
I'll start there and keep looking for what might be the best option for me. I really appreciate the information. Hopefully you were able to gain a little something from me as well. You never know, you might pick up treasure hunting yourself one day. ;) Take care
 

wayneh

Joined Sep 9, 2010
16,384
I'll start there and keep looking for what might be the best option for me. I really appreciate the information. Hopefully you were able to gain a little something from me as well. You never know, you might pick up treasure hunting yourself one day. ;) Take care
Here's an example of a boost converter. It's probably overkill for your needs but even so is inexpensive. Just a starting point.
https://www.amazon.com/Onyehn-LTC1871-Converter-Adjustable-Regulator/dp/B07GJDNKG9/ref=psdc_10967761_t1_B0752TRXDC
 
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