Hello,
the Whites Surfmaster PI Pro detector comes standard with a 8 cells battery holder that is meant to be used with alkaline batteries.
Unless you want your wallet be eaten out by the cost of always buying new batteries, you should use rechargable batteries.
The original battery older, as I said , holds 8 alkaline batteries that have a nominal 1.5 Volts each voltage that translates to 8X1.5V=12 Volts nominal output.
Rechargable batteries have a lower nominal output that goes down to 1.2 Volts each. Just replacing the 8 alkaline cells with 8 rechargables would mean to have a 8X1.2V=9.6Volts pack, that would be weak to power the PI Pro if you consider that the "pulse" is obtained by letting all the available battery voltage and current flow directly to the head windings for a very short time (a pulse).
The "induction" pulse strength is directly related to the initial voltage applied to the coil so having the right voltage is crucial for maximum detector performance.
This means that if you want to have the original 12 Volts nominal that a alkaline battery pack delivers, then you have to use 10 rechargable batteries (10X1.2V=12Volts).
Also the available battery current is important to have the highest possible current flow freely in the head without being slowed by the internal resistance of the battery. Nicads provide the highest current flow by allowing up to 20 X capacity max current compared to Ni-Mh that can provide just 5 x capacity max current. Also NIcads have a flatter discharge curve so they provide the nominal voltage for a longer time.
Having said that, I built a battery pack that overcomes the PI Pro battery compartment limitations by allowing use of 10 Ni-Cd batteries.
I used 10 Sanyo KR-1100AAU 1.2V 1100 mah Ni-Cd rechargable batteries that I got from RS-Components http://www.rs-components.com/index.html .
Since a 10 AA batteries holder does not fit in the PI Pro battery compartment, the batteries have been glued together with silicone, soldered in series and tape wrapped for solidity and assembled in such a way to let 3 of them fill the 3 slots that are on the bottom of the PI Pro battery compartment
!.
I also replaced the weak original battery connector (9 volt type)with a quick disconnect, locked, RC Tamiya type for a rock solid connection.
A note: you need a battery charger able to handle 10 cells at once. I got one from Robbe (Austria) http://www.robbe.com/ that can charge almost anything.
Here are pictures...
The batteries..
[attachment 17635 P1240124.jpg]
Battery Specs
[attachment 17637 cell.jpg]
Assembled Pack...
[attachment 17638 P1280139.jpg]
The pack in its place
[attachment 17640 P1280140.jpg]
Professional Rechaging
[attachment 17641 P2090145.jpg]
Cheers!
the Whites Surfmaster PI Pro detector comes standard with a 8 cells battery holder that is meant to be used with alkaline batteries.
Unless you want your wallet be eaten out by the cost of always buying new batteries, you should use rechargable batteries.
The original battery older, as I said , holds 8 alkaline batteries that have a nominal 1.5 Volts each voltage that translates to 8X1.5V=12 Volts nominal output.
Rechargable batteries have a lower nominal output that goes down to 1.2 Volts each. Just replacing the 8 alkaline cells with 8 rechargables would mean to have a 8X1.2V=9.6Volts pack, that would be weak to power the PI Pro if you consider that the "pulse" is obtained by letting all the available battery voltage and current flow directly to the head windings for a very short time (a pulse).
The "induction" pulse strength is directly related to the initial voltage applied to the coil so having the right voltage is crucial for maximum detector performance.
This means that if you want to have the original 12 Volts nominal that a alkaline battery pack delivers, then you have to use 10 rechargable batteries (10X1.2V=12Volts).
Also the available battery current is important to have the highest possible current flow freely in the head without being slowed by the internal resistance of the battery. Nicads provide the highest current flow by allowing up to 20 X capacity max current compared to Ni-Mh that can provide just 5 x capacity max current. Also NIcads have a flatter discharge curve so they provide the nominal voltage for a longer time.
Having said that, I built a battery pack that overcomes the PI Pro battery compartment limitations by allowing use of 10 Ni-Cd batteries.
I used 10 Sanyo KR-1100AAU 1.2V 1100 mah Ni-Cd rechargable batteries that I got from RS-Components http://www.rs-components.com/index.html .
Since a 10 AA batteries holder does not fit in the PI Pro battery compartment, the batteries have been glued together with silicone, soldered in series and tape wrapped for solidity and assembled in such a way to let 3 of them fill the 3 slots that are on the bottom of the PI Pro battery compartment
!.I also replaced the weak original battery connector (9 volt type)with a quick disconnect, locked, RC Tamiya type for a rock solid connection.
A note: you need a battery charger able to handle 10 cells at once. I got one from Robbe (Austria) http://www.robbe.com/ that can charge almost anything.
Here are pictures...
The batteries..
[attachment 17635 P1240124.jpg]
Battery Specs
[attachment 17637 cell.jpg]
Assembled Pack...
[attachment 17638 P1280139.jpg]
The pack in its place
[attachment 17640 P1280140.jpg]
Professional Rechaging
[attachment 17641 P2090145.jpg]
Cheers!