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TDI Beachhunter..... Going Back To 12v And Why

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I opened up my TDIBH the other day for some fiddling around and checking out a few things. I powered up the detector with all of the guts and board opened up and had it hooked up to the 14.8v (4 x 18650 cells) battery pack. I had it going for just a few minutes when I gripped the circuit board as part of my “fiddling” around......well I dropped the board and swore a bit in response the burn I was expecting on my fingers. Well it turns out that on the opposite side of the board behind where the big capacitors sit is some sort of heat sink and I can tell you the heat from this spot was something else. The detector has and runs just perfect but the hotspot really surprised me. 
I decided to hook up the 12v battery pack and let it run for a decent amount of time and it never got past a mild warm on the back of the board. That extra couple of volts is generating some serious extra heat.....bit like on the heat sink area of the CPU chip in your computer.

I honestly don’t know if the detector can handle this extra heat long term but I’m not taking any chances. I’ve moved back to the 3 x 18650 battery pack which I knocked up when I first got the detector. There is a slight loss in depth but surprisingly not too much. I feel the performance of the 11.1v Lithium setup is maybe 1 to 2 inches behind the 14.8v “hot pack”.

You can see in the photos the big caps on the detector and where the heat comes from. The other photo is my 11.1v pack which packs some punch and lasts much longer then the stock NiMH pack.





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Always wondered about that. Wonder if the older TDI's had that issue with heat and maybe that is the reason Whites toned them down?

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  • Steve Herschbach changed the title to TDI Beachhunter..... Going Back To 12v And Why

This issue is likely more extreme in the Beach Hunter model than the dry land versions because of its water tight enclosure preventing convective cooling.  Were the 'big box' models, particularly the Pro which ran out-of-the-box at higher voltage (and current??), a significantly different circuit (and with different heat dissipation solutions)?

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I’ve never owned other TDI models so can’t make much comment regarding that. So the board was seriously hot even completely exposed to the outside air so I can only imagine with it all sealed up. My electronics is quite basic but the spot behind the 4 big caps was the area of concern. There is no discolouration or noticeable problems on the board in relation to the heat and the detector runs just fine but I weighed up my options and decided to err on the side of safety by throttling back to a 12v setup......with the serious heat and 4 Lithium cells.....well you know where I’m going with this 💥 

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8 hours ago, GB_Amateur said:

This issue is likely more extreme in the Beach Hunter model than the dry land versions because of its water tight enclosure preventing convective cooling.  Were the 'big box' models, particularly the Pro which ran out-of-the-box at higher voltage (and current??), a significantly different circuit (and with different heat dissipation solutions)?

I suppose I could wedge the detector inside of my wetsuit and be very happy with the inbuilt heater 🥵

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For those that PM me regarding the battery setup.....very easy but remember this is for a 3 cell @ 3.7v (nominal per cell) for a total 11.1v nominal. The 3D printed 3 cell packs do not fit the TDI BeachHunter or BeachHunter ID 300 battery compartment.

Parts needed are the Whites AA battery holder and an 18650 3 cell battery holder. The 18650 holder has to be trimmed down in height on both short ends (seen in photo) and the Whites AA holder has the floor taken out to accommodate the 18650 battery holder. Very easy and then solder up +- leads.

Just support the whole setup with your hand and she slides in perfectly or maybe tape the 18650 holder flush with the bottom of the Whites battery holder.


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No problems at all........the last thing I wanted was to be leaving a smoke trail behind me. Personally, the extra depth of 1” to 2” by running at 14.8v just isn’t worth it.

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I have used the 14.8 since day 1   I have never used the 12 volt battery.

I have countless hours on it in 2 years it is working just fine. 


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