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Stabilized 12v Pack For TDI Bh

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Hi! after a year of snorkeling with TDI BH I concluded that I can clearly note the sensitivity goes down ones the voltage of my battery pack goes down.

Other conclusion was that even at 12.6V the TDI BH is noisy underwater at maximum settings: it reacts to the waves.

Thus at the moment I really prefer to have just a stabilized battery pack. For my experiment I took a couple of 21700 5aH Li-Ion cells and a dc-dc booster board.

the plan is to get "one hunt" battery pack.






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Could you give a little more explanation?  Those appear to be 3.7V batteries.  Is the circuit board some kind of voltage regulator (switching regulator) that steps up the voltage?  And the switching circuit doesn't introduce EMI?



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right, the plan is to connect 3.7v 1s2p -> bms -> step up converter.

Each cell has huge capacity of 5000 mAh, so the pack will turns to have around 30 Wh (stock battery has 26.4 Wh).

EMI will be one of the points to check. theoretically all the detector's pcb has some sort of stabilizers integrated. these has to work the same way as my pcb.

... wondering why TDIs are voltage dependent? it doesn't stabilizes the voltage? Why?

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Here is an update on TDIBH stabilized 12v Li-ion battery.
Well it works great. The step up module does its job just fine, but the protection PCB triggers immediately when the detector is switched on.
Thus for the moment I had to took out protection board (will search for the replacement).
Here I'm using 6 X 3.7 v batteries in parallel to boost it to 12v. The capacity is around 40.4 wh comparing to 26.4 wh of the stock rechargeble battery pack. ...and the voltage is stable!







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18 hours ago, pjrough said:

The capacity is around 40.4 wh comparing to 26.4 wh of the stock rechargeble battery pack.

By 'stock rechargeable battery pack' are you referring to the orange labelled (and sealed) NiMH pack supplied by White's?  Here I'm referring to what is supplied with the TDI/SL (and works for other White's detectors such as the MXT).  I don't know if they changed the pack footprint for the TDIBH.

So a 50% increase in battery life.  How does that translate into operating hours?


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Right, I referred to 2200 mAh NiMh pack that is coming with your machine.

Logically, the capacity should increase by 50%. But I have never used my NiMh battery pack, thus I don't have exact numbers to confirm.

One's the TDI is not voltage regulated metal detector, I can imagine that the current consumption drops one's voltage of the battery pack drops. Thus standard 2200 mAh battery could last longer compering to identical capacity, but stabilized one. (Just because at some point standard battery pack will provide 10v, so the current will drop, giving you less depth).

My goal was to make a one-hunt battery pack but with stable voltage. I have an extra capacity just in case if I decide to increase battery voltage in the future....

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Regulated battery burned down (step up converter burned down). The reason is too high current consumption when the TDI start. It is possible to solve the problem by placing an extra capacity at the input of the DC converter....


...but I have better idea. 

Here is a new version of regulated battery. 
This time using protected 2s3p Li-ion battery, and high quality step-up converter. I can pump-up battery easily to 16v. For the moment keeping it at 14v. Already tested and it works great.











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Here is a little feedback for regulated battery pack. it works just great! I set 13.4V and ended up with capacity of around 2900 mAh.

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On 7/10/2020 at 5:13 PM, pjrough said:


Here is a little feedback for regulated battery pack. it works just great! I set 13.4V and ended up with capacity of around 2900 mAh.

Nice and clean work...I'm waiting four Samsung 30E cells now. 3450mAh should be fine and last 6 + hours.Talking about noise I ended up raising delay up to 18/19uS to stay quiet without continue treshold retuning. 

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TDI is voltage dependent, so going for 16v battery pack (freshly charged 4s lipo arrangement), you will have to go for even lower delay settings. ...which kinda surprise my, because even diving in rocky areas I rarely go lower then 15uS. 

With voltage regulated pack I can still use TDI with low 10uS delay, just because the voltage is fixed to 13,4 v all way through the discharge cycle.

Lower capacity of the battery pack in my case is due 2200mAh old scrapped cells i am using in it. It was an experiment, that turned quite successful.

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