Tdi Pro 5 x 18650 high voltage battery build.

[karelian65]

I've played around with a modified Tdi Pro now for some time, smoother threshold and a bit of extra sensitivity. I have upgraded my Tdi Sl battery to 16 volts with a decent gain in performance so the idea of boosting the Tdi Pro is interesting. Looked at the Reidman battery pack made a long time ago in the USA, 21 volts fresh off the charger for a consistent 18 volts plus.
Five cells in series with a heat shrink wrap, a dedicated charger etc. All the parts have finally arrived in the mail, so I am good to go. Will built the battery pack during the coming week and follow up with more information to let you know how it performs. That will push the modified Tdi Pro to its limits.
All the best, Karelian.

 

[Joel418]

Hi Karelian,

Just wanted to see if you had made any progress on the battery build?
Thanks

 

[karelian65]

Just waited for the heat shrink wire covers, purely cosmetic. Had to chase after the plugs as well, the ones that plug into the machine. Too many distractions.. Parts are assembled and ready to go.

Soldering iron kit.
Heat shrink plastics and rubber for a tidy look.
Again I'll get it done pretty quick, now that I remember...

 

[karelian65]

Just checked my parts, everything located and ready to go. I'll take a few snaps as i go and include diagrams, so if anyone wants to do the same it should be simple enough.
Lots of distractions this year, so I forgive myself for forgetting about this little project. Ok, all systems go.

 

[Joel418]

Thanks for the update, looking forward to the test results
Joel

 

[karelian65]

2.1mm connector wiring instructions.

 

[Joel418]

Hi Karelian,

Have you got a link to where you got this kit from or did you custom make it yourself?

 

[karelian65]

The idea came from an American named Reidman who made 4 x 18650 battery pack for the TDI SL and 5 x 18650 pack for the TDI PRO. He didn't post OS and is no longer in the game. Just researched 5 x 18650 power packs and found the chargers and circuits. All purchased on EBAY. Just need to make sure it fits inside the PRO and has the correct 2.1mm connector. So no kit, enough parts to build one more battery as extra if the first is a success. I'll do a parts list and links etc when I do the full write up later.

 

[Joel418]

Fantastic, thanks

 

[karelian65]

First stage assembly, soldered tabs together as per diagram. Hot glued cells in position and placed PCB where I want it. Next step is to wire up the PCB and connect the plug.
Final stage is heat shrink wrap etc. Stage 1 soldering and gluing is now complete.. moving along..

 

[karelian65]

Connected the PCB and taped over all the connections.

Tape offers peace of mind and added protection.

Did a bit of a rough job with the heat shrink, hair dryer on hot works the best.

Just needed to connect the plug.

Not a hard project, fiddly though with the soldering.

It will be interesting to see what the added voltage means in terms of depth.. More to come..

All the best.

 

[karelian65]

Just images of the factory battery and the higher voltage battery. Being a bit smaller the 18v battery has more room whilst the factory one is a tight fit.
Testing and parts lists etc to come in the next day or so.

 

[karelian65]

Tested three standard factory battery packs, all charged a couple months ago. All three were close to 16.5 volts. Fully charged the 5 cell pack should come in just over 20 volts. Looking back to the Tdi SL there was a small but noticeable improvement in depth and performance going from 3 x 18650 to 4 x 18650. With the Tdi Sl there was the knowledge that the machine was running at its best for hours. So will there be the same improvements with the Pro? Early Reidman battery users in the US indicated that there was an improvement. I'm in Melbourne, so an air test is the best I can do for the moment. Reg the Tdi Guru (RIP) made the point that higher voltages lend themselves to using either White's or Miner John coils, something to do the the resistance on Minelab compatible coils.. So tests will be with the White's and Miner John coils I have. More soon.

 

[Joel418]

Thanks for the update,
I've bought a second hand 14x9 NF advantage (in the post). I figure it's got to be an improvement over the standard 12inch whites mono

 

[karelian65]

That NF 14 x 9 is about the perfect size, huge improvement over the White's 12" mono.

 

[karelian65]

So a quick air test today using the modified Pro and higher voltage battery. Used the Miner John 14 x 8 mono. High EMI today, looks like everyone is working from home today. The Pro was stable and smooth at a gain of three.... I pushed it to six for the test. Pulse delay was 10, Ground Balance was OFF, conductivity was in ALL. Played with the frequency in an attempt to minimize the EMI, to no avail..

There were no issue with the machine, it ran normally, no heat or explosions. Battery worked fine, I'm guessing at this early stage that it is going to work out and the higher voltage is not damaging the machine as far as I can tell.

A 1 grain gold ingot came in at 10 cm, just a 1 cm increase from the stock battery.
The half gram gold coin was 37 cm or a 2 cm increase over the stock battery.
A half Sovereign came in at 46 cm or a 1 cm increase over the stock battery.

The Tdi Pro in both stock and modified varies in performance from day to day, sometimes I can get gain really high, then other days they play up and I'm pushing to get three or four on the gain.
In contrast the Tdi Sl consisitently hits max gain regardless of EMI etc. A far more consistent machine, but still outperformed by the Pro machines.. These factors are mostly evident in the suburbs, take them bush away from the EMI and they do better.

So even under difficult conditions there is a small increase in performance, marginal but real. A full days detecting would see me use two of there higher voltage battery packs, ensuring peak performance at all times.. Parts list etc more to come.

I've removed the heat shrink wrap from my first attempt. Will apply lessons learnt and give it another go.

 

[Joel418]

Excellent, I was a bit worried it might be too big but I really wanted to cover a lot of ground when I head to Mogo in a couple of weeks

 

[Joel418]

Bummer about the EMI being so bad but a 10% increase on the small ingot and gold coin is nothing to sniff at. Well done. Once your parts list is up I think I'll give it go myself.

 

[pulsetrain]

Hi Karelian, very interesting project you have built and nicely set out instructions. :Y:

I was thinking of building one myself to see if I could get a bit more depth.

I took some readings from my TDI and found that power usage went up from [email protected] to 13.9W@18V.

I also gave the TDI 22V for a while and didn't notice any problems (or smoke).

Some rough calculations for your NCR18650 pack came out at 4 hours 12 minutes before the pack drops to 15V.

Just wondering how close that number is to what you are seeing.
I usually only hunt for a few hours at a time, so a four hour capacity would be ideal.

 

[karelian65]

I will do a full review or field test after the travel restrictions are eased November 8. Still need to test the charger and make sure everything works as it should. When i go prospecting I'll take an amp meter with me. Four hours sounds about right, max performance and longer battery pack life etc. Parts list to follow with the full field test. A day or three out of Melbourne will do me good, modified Tdi Pro with high output battery pack will see some use as will the GMX. I'll post results not long after I return from the trip. All the best.