replace 9v with 18650 Lion - bounty hunter discovery

[Lavabo]

Hello all
This is my first post, im happy i had find a technical forum on MD.
I was looking to get rid of 9v Battery for my metal detector and i could not find any info on it, so i did it myself....so im happy to share what i did to my Bounty Hunter discovery 2200

Im a computer tech for schools and i have defect battery from laptop where i can then salvage some of the 18650 inside...
Those battery are awesome, i already bought a Fenix frontal light and a laser that use these. For charging im using an intellicharger i4 pro, but i plan upgrading soon.

Since i already made a battery swap on my Roomba to 18650 also, i wish i could make it on my metal detector. I just started with metal detecting this spring with a BH discovery 2200. I really love it and looking to get a better one or build my surf PI
I opened my main circuit to find that the 2 9 volt battery use two circuit .. at first i thougnt it was 2x9V for 18V.
BC1 and BC2 circuit.
Yesterday i tried both circuit, one seems for the main board, and the other for Audio. I found i could put 3x18650 on one circuit and 1x4v on the other (audio) . Well tone are a bit on the low battery side.. but maybe ill add another 18650 (total of 2) and see the improvement.
I had no idea what was the power circuit.. but i was guessing it was protected so putting 12 v wont harm it much.
Enough, here are the picture

i used a 4x18650 batt holder, bought on aliexpress for cheap..


There is 2 screw hidden unther the facia.. just peel off the corner...


Voltage of 1x18650:


Voltage of 3x18650


Used molex connector


I just welded the wire on the 9v connector


Its working


For now i just fixed the battery holder on the stick


Close up of the mainboard.. Rev4 ... is there newer revision


Whats the j5 conenctor for .. its not used here


I will modify the battery holder this winter, this is my version 1.0... im waiting to have more ideas .... maybe i could put them in the main shaft ..
For now i went in my backyard and it worked well

[bernte_one]

dont use the 4* holder

on Internet you con find 3s or 4s charging pcb
https://www.akkuteile.de/4s-pcb-keep...-26a/a-200506/

directly solder the cells together an connect this protection board, so you dont Need to take the single cells off the holder for charging the single cells
you can install this as internal power source just add a charging connector on your enclosure an a Switch on/off/on mode one detector on mode two charging on

[Lavabo]

hey thanks thats a great add on!! thank you!
What about the input voltage on BC1 circuit ? As i said im giving 4V on BC1 and 12v on BC2.
When you use 9v batt, BC1 and BC2 get 9 v each... i guess BC1 only need about 5 volt to operate what i think is the audio circuit.

[kt315]

Bernd is right - you can not so simply charge cells connected in serial. you have to use especial additional board for charge (also at aliexpress and ebay).
a converter gives 9V. all info in RAR.
http://www.avral.ru/50af35b7d3e60eb80672bae1b5108351 (click OK, do not input a password there)

though you can use two cell in parallel and to charge them both. you may too try to use Step Up converters
http://www.ebay.com/itm/XL6009-DC-Ad...UAAOSw~gRVs4zr

[junkhunter]

the bounty hunter is crap i have been told i had a quick silver wish i still had it great metal detectors for the price

[kt315]

i had asked forum but tell again. BH has set some type of converter inside. pics again.
bad thing nobody did not be able to give detail information, but one answered that is used LT1304.

[Skippy]

Connector J5 is almost certainly the serial programming port for the microcontroller IC. There is an almost identical arrangement inside the Fisher F2/F4, which are obviously 'big brothers' of your machine.

[kt315]

ok guys. i got the converter bought at ebay after very long waiting and will tell the mod - how to convert two 9 volts power supply BH.

[homefire]

What kind of current can that supply ?

[kt315]

http://www.ebay.com/itm/DC-DC-Conver...gAAOSwbYZXf2R2

50mA for 12V. must tune it to 9-10V. enough for a VLF. this 5pin chip is noname, so can not tell about the data from a datasheet.

[Skippy]

I've looked at the photo of the module on that eBay link. I reckon the feedback divider network is made from the 220K (224) and 24K (243) resistors. This divides the (12 Volt) output down to 1.23 V, to suit the IC's internal reference.
SO if you replace the 220K resistor with 150 K, you will likely get 9 Volts. Or for a quick test, put 470K in parallel with the 220K (to make 150K). Keep it SMD, long leaded resistors will likely mess things up, it may run at over 1 MHz.

[Funfinder]

This circuit wastes just energy, you also can simply use 3 small
3,7v LiPo-accus in series together with some balance-charger
as the Blisstool has realized it but with more powerful cells.

[Skippy]

"You also can simply use 3 small 3,7v LiPo-accus in series"
Presumably you mean 6 x 3.7 V LiPo, similar to what Lavabo said he tried in the first post in this thread ?? Plus, he wants to use 18650's as he has plenty of them, so using small LiPo's doesn't suit his request.

[kt315]

changed 243 24k to 47k pot. tuning gave me approx 32k for 9+ volts. have to find a SMD resistor to set finally.

[kt315]

This circuit wastes just energy, you also can simply use 3 small
3,7v LiPo-accus in series together with some balance-charger
as the Blisstool has realized it but with more powerful cells.

i did not create new thread, but my case is TWO 9 volts battery power supply in BH QUICK DRAW II.