TDI Air Test & Battery Notes

[Mark Gillespie]

After all the excitement and comments about air test I decided to do several test using my TDI SL with stock 12” coil.

First off I charged the battery pack (11.35v).

Set the machine in a very good area with the coil elevated with the following settings:

Gain max

Ground balance off

Pulse 10

Conductivity switch, all

 

At these settings, using a US nickel I got a solid 12 to 12 1/4” air test, light, but repeatable audio.

I checked the machine every half hour and there was no change in air test distances.

After four hours still no difference.

 

I turned machine off and checked the battery pack voltage (9.63).

Amazing discovery, the machine must have a very good voltage regulator, for the machine to perform the same as with a full charge pack.

One notable observation:

Gain of 7 to max gave the same results in air test, no difference, even after 4 hours of continues running.

Drop the gain to 6 and the nickel could not be heard at 12”, but around 11 ¼”.

 

 

Fast forward:

Installed a fresh set of Rayovac batteries in my battery pack

These measured a total of 12.8 volts.

Did the same set of air test and the results are as follows:

Air tested a nickel at 13 1/4”, faint but repeatable audio.

This distance was continues for around an hour, then dropped to 12 ½”.

After 2 hours the air test was the same as the stock rechargeable battery pack.

Shutting down the machine and checking the voltage indicated 11.35 volts.

 

I know you can buy a battery pack with 14.8 volts which will obviously increase the depth performance, but I wonder what the maximum voltage that could safely be used in my unit!

[Steve Herschbach]

The official word from White's was 18V http://forums.whiteselectronics.com/showthread.php?68143-TDI-SL-max-voltage-permitted The battery that ships with the TDI Pro is 14.4V 4.4Ah Li-Ion

Prior thread here on TDI SL and batteries...

 

[auminesweeper]

Good Info Mark, but you should try it using a Quarter with the GB on and sweep slowly because the SL is a Low and slow machine Slow than using an FBS machine in an Iron filled site, at first you will notice that it will signal between 14 to 15 inches and then it will track out the coin and then see it at about 11 and a half inches, when it does that then bring the coin up to the coil where it almost makes the overload sound and take it away quickly and then sweep it in front of the coil again and it should make a soft noise at about 15" plus and then after a couple more sweeps it will track it back out to below the 12 inch mark, Ok

See here,

john