Making a SCR-625 103 volt battery

Making a 103 volt battery:

Make and use a temporary battery first, until you are certain your mine detector works. You would need a minimum of 10 batteries, and battery clips, and some jumpers to work. A picture of a mock up battery, but just using 5 batteries, and taped connections instead of soldered.:

You will need some typical shop tools and soldering skills here. You will need eleven (or ten) 9 volt battery clips, a 1"x1" inch ”L” shaped aluminum stock from a home supply store, cut to 11 1/4 ", two pieces of 1"x2” oak x 1 5/8" long, small wood screws, electrical tape, and the copperclad. You will probably need to reduce the thickness of the 1x2 to about .65 inches (1.75 cm), or reduced by nearly the thickness of a power saw blade.The copperclad can be purchased from Mouser. A very thin piece of steel might work in place of copperclad, with a ring terminal to attach the wire.  The construction is too difficult to describe, just look at the pictures and think about it. A lot of trial and error is required. Ebay has the best price on 9 volt battery clips, but the quality may be poor. Be sure to get battery clips with the wire coming out the side - look closely at the pictures. 3/32 heatshrink is needed to insulate solder connections, do not rely on electrical tape to insulate connections.Wrap the whole battery, except the ends, in electrical tape, when complete. Scotch Super 33+ vinyl electrical tape is a top quality electrical tape. Some cheap brands are good, others are bad.

Use a good, name brand battery. Based on some specs I've seen online, they might last about 25 hours.

June 2022 - Eleven new 9 volt batteries is about 105 volts, if you wanted to use just ten batteries, you would have 95 volts to start. That will work fine, but not last as long. The SCR-625 will operate with a battery voltage as low as 75 volts.

When inserting the 103 volt battery into the amplifier box, place the positive end in first, push the negative end down last. Remember, the battery voltage is 103 volts, touching one live place at a time is OK, touching two live places at a time can be surprising.

1.Be sure to put a layer of electrical tape between the layers of batteries.

2.The battery is a larger circumference than the original, so you will need to remove or shave down the battery holding block in the amplifier.

3. Be careful not to pinch or kink the wires.

4. Adjust the negative battery contact of the amplifier in or out for a snug battery fit.

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