Gp3000 Diy Battery Pack

[Dutchman4]

I am considering to build my own battery pack for GP3000.

I plan to eliminate the Coiltek Battery/Regulator unit.  It appears the OEM battery supplies 6V and the Coiltek Battery/Regulator recommends 6.7V for GP series.  I can choose to use Lithium-Ion battery cell at 3.2V with two in series producing 6.4V or choose Lithium-Polymer battery cell at 3.7V with two in series producing 7.4V.  My question/concern is that a fully charged Lithium-Polymer cell can reach 4.2V so twice that is 8.4V so is that too much voltage to supply directly to the GP3000?  I assume the GP3000 has an internal regulator for the incoming battery supply.   

[RONS DETECTORS MINELAB]

The GP-3000 seems to handle up to 7.3v but I have never tried to push it farther than this even though I was told by an electrician that they our internally regulated and will supposedly shut down if over 8 something volts. He also said he would not want to tax this safety feature.

I use a step down converter to regulate the voltages down to 7.2v and can run all SD/GP & GPX series detectors on this voltage using two 3.7v 18650 batteries in series or with more 18650 batteries run in parallel for a longer run time still providing the 7.2v output.

Two 18650 batteries in series do charge up to 8.4v which is fine for the GPX series but like I said before I regulate them down 7.2v as I would not want to run 8.4v on the GP series unless someone could verify that its internal regulator capabilities and limits could handle this higher voltage.

[bklein]

Use a buck boost converter from eBay.

[Doc]

As the person who started this whole thing with being able to use the NPF960 Sony Lithium Ion batteries with a Regulator and now my Nugget Stalker Regulator Amplifier, here's is my position on this.

Back when I first started having Coiltek manufacture them, we were using the SD2200's.  You could over drive the SD2200's and actually kick them up to 7.3 volts.  (A fully charged Lead Acid Battery is 6.7 volts)  Some guys were actually taking two lead acid batteries of 4 volts and running them together to produce over 8 volts with SD machines.  (They were killing it!  In terms of finding gold.  One of them did however burn out a component.)

Those 7.2 V Lithium ion batteries actually charge up to 8.4 volts with a full charge.  The regulators stepped that down to 7.3 volts and kept that voltage constant all day.

Now along comes the GP units and they had Dual Voltage technology which sort of defeated the ability to overdrive the detector with high voltage because the GP's were regulating the voltage.  So we regulated the 7.2 batteries down to 6.7 volts to mimic a fully charged 6 volt lead acid.  Remember we were regulating the Lithium 7.2 volts down from actually 8.4 volts to 6.7 volts which is what that lead acid battery is when fully charged.  With the COILTEK regulator we gave you a switch to choose where you wanted the voltage regulated down to.  6.7 or 7.3.

Dutchman, the answer to your question is go with the two 3.2 volts.  for 6.4 that will probably charge to about 7 volts.  Anything more than that is overkill because the GP just regulates it down anyway.

Or you get the Nugget Stalker Gold Screamer for the GP and use SONY batteries, and get a constant 6.7 volts all day long and 500% adjustable increase in volume.

Doc

When I started manufacturing the regulators I decided to put an amplifier in it that actually allows you to pump up the volume and can give you 500% more volume than the detector itself,  (Way too loud if you run it wide open.)

On the regulator for the SD and GP's (4 pin plug) I decided to only allow the regulator to take that 8.4 volts down to 6.7 volts not 7.3.  You get a constant non-fluctuating 6.7 volts all day long.  This is important because we found that using the standard lead acid battery that is 6.7 volts fully charged, it starts to drain immediately.  Within 2 hours you lose 20% of your depth.  This is also why these machines can sometimes start to become unstable towards the end of the day.

I decided to only allow a 6.7 volt output because these older machines, SD's and GP's can no longer be serviced.  They are old and I don't want to be responsible for overdriving these machines with a voltage that is above and beyond what a stock battery would produce.

Now the GPX series is different.  They use a bank of batteries that equal 7.2 volts and fully charged to 8.4 volts with no regulation.

So keep these things in mind when deciding what you want to do.

To answer your question go with two 3.2 batteries that will probably charge to 7 volts.  There is no sense in providing more voltage than that because the GP will just regulate it down.

Or take a look at the Nugget Stalker Gold Screamer that automatically gives you the correct voltage and a bonus adjustable 500% increase in volume.

Doc

[Northeast]

2 hours ago, Doc said:

Back when I first started having Coiltek manufacture them

Hi Doc, I never realised these were from your stable but glad they are as I can ask you a query  🙂 

I have one of the Coiltek built set-ups and it is used on a GP 3500.  I can plug ear buds directly to it and can also plug a bluetooth transmitter into it and audio works well. However, if I plug a speaker directly into the Coiltek unit the speaker will not work (I can hear a very, very faint signal but that is all).  Are the Coiltek units supposed to be able to run a speaker and therefore something is broken in mine or would a speaker only work on your newer model you speak of above that has had the amplifier built in?  

2 hours ago, Doc said:

Now the GPX series is different.  They use a bank of batteries that equal 7.2 volts and fully charged to 8.4 volts with no regulation.

Another query if I may re: the comment highlighted above that the GPX has no internal regulation.  Over on the DP Minelab forum I had asked some questions re: building a light-weight battery set-up for my GPX 5000 and I have had a few discussions with David at Detectormods about it.  The concern re: building something is that we guessed it would need to have some sort of regulation in it as the GPX is supposed to run at 7.2 volts but fully charged the batteries I was looking at would be about 8.4 volts.  But, is that actually not a concern?  Can a GPX happily run at 8.4?  What is the maximum a GPX will run at without damage?  

Cheers, NE. 

[Doc]

The stock battery of a GPX5000 charges to 8.4 volts.  The detector actually shuts down at 7.2 volts as it senses it as a low battery.

Internally that big ol' aluminum case has exactly the same batteries that a SONY NPF960 battery has.  The only difference is that Minelab puts their charging regulator in that case as well as some circuitry that is supposed to boost a speaker.  It does a nominal job of amplification.  I also think they made the aluminum battery the same size as the old lead acid battery because it fit the case on the back of the harness and they probably had a bunch of harnesses from previous model detectors already made.

A lot of folks don't understand that a AA 1.5 volt battery that reads 1.5 volts is DEAD.  A fresh 1.5 AA battery is 1.58 volts.  Your working voltage is .08 volts.  When that is gone your battery is dead.

Same with a 7.2 Lithium ion that charges to 8.4 volts, 1.2 volts is your working voltage, when the battery reaches 7.2 volts the battery is essentially dead and needs to be recharged.

So 8.3 to 8.4 volts on a GPX is fine that is what it is made to run.  There probably is some internal regulation because I think in the GPX series they are probably still using Dual or multiple voltage technology.  When you mix the pulse length (which is what the soil timings are) with various voltage strengths and you have the ability to find a variety of sizes of gold at various depths.

Steve Herschbach can probably explain all of this better than I.  Steve usually does a deep dive on the patents to see what exactly is going on inside those detectors.

Doc

[Doc]

QUOTE:  I have one of the Coiltek built set-ups and it is used on a GP 3500.  I can plug ear buds directly to it and can also plug a bluetooth transmitter into it and audio works well. However, if I plug a speaker directly into the Coiltek unit the speaker will not work (I can hear a very, very faint signal but that is all).  Are the Coiltek units supposed to be able to run a speaker and therefore something is broken in mine or would a speaker only work on your newer model you speak of above that has had the amplifier built in?  

 

Sorry I didn't see this question.

The Coiltek units do not have an amplifier.  They don't have enough punch to drive a speaker.  There is no amplification.

Doc

[Aureous]

All of my GP's and GPX's that Ive used in the past decade or two have run exclusively on unregulated 8.4V camcorder batteries. The higher the mAh, the better. Just a simple dremel out of the plastic to allow a twin core DC cable and adapt the power connection for a simple twin-plug DC connector. Half hour of work. You get a whole day of use (8 hours) from each battery. The camcorder batteries are cheap and often come with a charger included. Ebay, Amazon, Aliexpress etc.

[RONS DETECTORS MINELAB]

50 minutes ago, Aureous said:

The camcorder batteries are cheap and often come with a charger included. Ebay, Amazon, Aliexpress etc.

https://www.amazon.com/gp/aw/d/B07Z3TGC7B?psc=1&ref=ppx_pop_mob_b_asin_title

https://www.amazon.com/gp/aw/d/B0BZR891KG?psc=1&ref=ppx_pop_mob_b_asin_title

These Vemico packages on Amazon have the good quality Samsung 18650 batteries inside them. The 550 have two batteries in series and the 970 has 6 batteries running parallel for longer periods of use. I prefer the 550 as they are lighter though and I just carry more of them, they even come with a duel charger and a carrying case.

These batteries also have a protection board in them that will protect a lithium meltdown if voltages get shorted or reversed.