GP3000 Voltage

I'm running my GP3000 with the standard 6V battery (about 6.3V fully charged). Would there be any improvement in performance if the voltage was increased slightly ? I've read here that members are running SD's at higher voltages, with good results. For some reason, (I think I read it on this forum, but can't find it), a figure of 6.8V sticks in my mind. Is it worth mucking around with the voltage ?
panhead

panhead wrote:I'm running my GP3000 with the standard 6V battery (about 6.3V fully charged). Would there be any improvement in performance if the voltage was increased slightly ? I've read here that members are running SD's at higher voltages, with good results. For some reason, (I think I read it on this forum, but can't find it), a figure of 6.8V sticks in my mind. Is it worth mucking around with the voltage ?
panhead

Hi Mate,
I would check your battery I have 4 standard batteries that charge to 7+ volts but settle down to 6.8v if left for a day or so. The ML-3000 has an internal voltage regulator and will work down to near 6.0 volts. Due to the weight of standard batteries both the wife and I use Reed Lion. Batteries.

Hi Panhead,
I used a Coiltek Pocket Rocket and it has a switch that flicks between 7.3v for SD and 6.7v for GP. Althought he GP has an internal regulator, I think it can handle 6.7 volts as it's limit, but a GP expert will correct me if I am wrong. The idea is that a standard 6v Minelab battery is 6v when almost flat, but will be about 6.7v when fully charged (and under load). So as you use the battery, after a while it reduces in voltage, hence maybe slightly reducing in depth performance. The idea of the regulator is that it supplies 6.7v constantly, whether the battery is fully charged or almost flat, giving you peak performance until the battery stops working from going flat.
Hope that answers something...
Cheers

Thanks for the replies guys. I didn't know about the internal regulator. I'm going to check my standard batteries Geof. I've got one on the charger now. So I'll be very interested in what it charges up to.
panhead

Keep in mind panhead, that the voltage you get with a voltmeter across the battery will be different to when you put a load on, ie the detector connected and turned on. The load could drop the voltage by a further .3volts.
Cheers

G'Day
Fully agree with Costas Dee When i had my 3000 i changed to the coiltek regulated battery system,light as,lasts all day ,quick charging and best of all the gold tally went up,it all worked so much better, the next best thing was a coiltek 14inch coil,gold tally went up again,hope this all helps.
Big Fella

I've had both my standard batteries on the charger now. They are coming off the charger fully charged at 6.8V, then after a short time they are settling out at 6.35V. Bearing in mind the voltage drop of 0.3V mentioned above that means they are putting out 6V. One battery came with the machine when I bought it, so I don't know how old it is. The other I bought new about 10 months ago. It looks like that's about the best they can do. I better start looking at getting the Pocket Rocket power supply. More volts=More gold (I hope )
panhead

Panhead, if the voltage regulator is the way you would want to go (that's what I would do), then you do have some options as I have outlined in another post re SD machines. Your options are:
-Coiltek Pocket Rocket
-Reeds Lucky Lark
-Ismael Jone's new wireless regulator
-older type 12v to 6.7v regulator.
Your decision would be based on whether wires are annoying enough, to need to go to the wireless system, weight would favout the Lucky Lark or Pocket Rocket, price would favout the older regulator. Once you've checked your budget and ticked the list, then you can narrow down which of the above best suits you.
Cheers

Wrong move Panhead. The voltage on all the GP series detectors are internally regulated to accept no more than 5.9 volts input.So 6.8 volts won't change the time of day on it,nor increase depth or sensitivity on targets as compared to say a fully charged gel cell at 6.3v. Different story if you were using a regulated battery system on the SD Series though,for they lack internal voltage regulation,so the higher regulated voltages as compared to the standard 6.3volt gel cell,can and do play a role towards the machines output performance.The only advantage you'll get,is in battery weight factor as in the "Pocket Rocket" or "lucky Lark" as compared to the weight of a 6 volt gel cell and the fact that regulated battery systems run a steady and constant set voltage all day,whereas power taken directly from a gel cell,steadily decreases in voltage with machine use over time.Pending on ground conditions,finding the right compatible coil to use with the 3000 is the key here.

Cheers kon61.

I stand to be corrected Kon, I did think the voltage regulator in the GP series was set to about or just over 6.7v. I believed that if you applied too much voltage to the GP, the regulator would blow and you would need to replace it. I also thought the "sweet spot" for GPs was 6.7v as that is the option for the switch on the Coiltek Pocket Rocket or the preset voltage for the Reeds Lucky Lark.You may be quite correct though as I have never owned a GP so therefore haven't learnt all the intriquencies of that series and I am only making asumptions on things that I have heard (which could be totally wrong).
Would be great if Ismael (or possible Mechanic) to maybe comment with their knowledge...
Cheers

No sweat Costas. You see the reason they went on to a regulated 6.7v Li system is so that people would believe that they're getting more performance when set at 6.7v,or as you say better sweet spot but when in fact they'er not.The fact remains that,as in the case of all GP series machines,their acceptable input voltage is capped at 5.9 volts.So whether an external voltage regulated power source is used such as the Lucky Lark for example, set on 6.7v,the machine gains nothing more or less than what the regulated 5.9 volts delivers in output performance,regardless of whether the Lucky Lark is set on 6.1v or anything in between to 6.7 volts. Yes,I too would like to hear from the electronic gurus if there's a difference on this one.

Hi Guys,

Well, the gp series should work on 7.2v as this is what a fully charged 6v battery can go up to. I don't know what the upper limit is for input voltage on the gp's, but there is a protection feature that will prevent the detector turning on when too much voltage is applied to the detector. At some point above the upper limit, there will be smoke, but I'm not sure how many volts that would be either And not willing to find out!!! Don't try this at home, or out bush for that matter, and don't jumpstart it from your car battery

Now internally the voltage is regulated to +5v -5v and -15v, and a few other ones in between too! So at minimum the battery input would need to be about 5.5v, however I think the low battery alarm kicks in at about 5.8v. The -5 and -15v supplies are below the battery negative. This is done using a switchmode power supply, so it can actually make a smaller voltage into a larger voltage.

So in my opinion I don't think changing the battery input voltage is going to make any difference to the performance of the detector as long as it is within its set limits.

Oh and Panhead, which battery charger are you using? The mains or car charger? Also have you checked the voltage with a different multimeter? Some can be inaccurate.

Cheers Mick

Thanks Mick, it sounds like I now owe Kon an ouzo.
Why then do they make the regulators for the GP series 6.7v religiously?
This is not the same theory for the SD series though is it, as they say the "sweet spot" for the SD is 7.3v?
Cheers

Hi Costas,

Don't know why they make it 6.8v, but probably because it is below the max voltage and above the minimum With a slightly lower than maximum voltage, when you turn the detector on the switch on current won't be quite as high, therefore less stress on the switching parts.

With the SD's a slightly higher voltage won't hurt, 7.3 sounds good to me, however on the 2200 it will not start up if the voltage is too high, once again, I don't know what this "high" voltage is. If anyone knows feel free to chime in! As the voltage drops on the sd series, the performance and ground balance will be effected, unlike the gp/gpx series.

Cheers Mick

Thanks Mick for the info.
I have tested my 2200 when I built a voltage regulator and found that at 7.77v (under load) the detector would sometimes turn on, and sometimes wouldn't turn on. Of course I only tried this a few times and quickly reduced the voltage to the next step down which was 7.3v. Here it worked fine. So 7.77v is still, in my opinion, no good and too much for the 2200d and probably slightly above it's limit. I have heard though, the 2000 and possibly the 2100 can handle a voltage in excess of 8.0v, but as that doesn't effect me, I have never followed that up.
Sounds like I still owe Kon that ouzo....
Cheers again

Hi Costa,

Yes the 2000 will go up to 8.4 and I suspect even more than that but I have never pushed it that far. I found that at 8.4v ground noise started to become a real problem, so never desired to go further. Also I don't like blowing things up for no reason! I generally run mine from the 6v gel cell, but if I'm using a large mono coil I will run fro a Li-ion pack that starts at 8.4v.
I think also the original green 2100's will take the same voltages as the 2000, but the newer v2's won't as they have the same protection as the 2200's and gp series.

Cheers Mick

Some day we'll have that ouzo out there in the field Costas. Your are also quite right about the 2200 switching off when approaching the 8 volt mark but not beyond it.My one switches off at 7.95v. One reason they made it a 6.7 volt regulator is as Mick said,a safe working voltage below the above allowable maximum and above the minimum required for the detector to switch on and function properly.Besides one has to think of how would it look,in terms of aftermarket GP Series battery regulator sales,if they were set on say 6.3 volts as a standard.In other words who would want to buy them (apart from the benefits of their lighter weight) when a fully charged 6.3v gell cell does the same job as the Lucky Lark or Pocket Rocket on 6.7v after charging,but at a fifth of the cost of both the other two? Costas,here's a tip,run your dd coils on the higher 7.3 voltage and your monos (where the ground allows),on 6.5 voltage.These 2 different voltages I've found,run each type of coil at peak performance,without making either coil to sensitive or to noisy.The reason they made the a safe working regulated voltage of 7.3volts is so you can safely use their accommodating in-line enhancers,for they fail to function or even blow up when pushed to the 7.4/5 volt limit. And Costas the earlier SD2000 will still function at close to 10 volts,but that's pushing all circuitry to the limit and a safe working voltage of about 8.0 volts was found to be more than appropriate for all round use.As for the 2100,same as the 2200,close to 8 volts,before one starts shiskabarbing the circuits.

Cheers Kon.

Well guys I'm not too proud to say I've learnt something new, and I thank you for it. One thing from this, I will certainly take this new found knowledge into the field with me, for those rare times I use the mono coil.
Thanks guys and cheers
PS I better buy that bottle of Ouzo and keep it in the car, in case I bump into you into the field, and Mick I think if I recall, you're a Bourban man...

Boy oh boy I'm glad I asked the question. I've learned a lot from this thread. I've been experimenting a little bit. I got my hands on a 2nd hand coiltek 12v/6.7v regulator, and got a 12v gell cell battery. With them connected I'm getting 6.72v coming out of the regulator. (Mick, I've only got the one multimeter, so I'm hoping that this reading confirms it's accuracy. Also, I am using the car charger to charge the 6v batteries. I don't have a mains charger). In order to save weight I went for a 3.2ah 12v battery. It's a lot lighter than a 12v/7ah, and the original 6v standard battery. I don't know how much detecting time this will give me. Maybe 2 to 3 hours ? But if I'm happy with the setup, I can always have another battery back at camp on the charger. After a couple of hours I'll be ready for a cuppa anyway. (I'll still have my 2 6v batteries as emergency backup). So given that the GP has an internal regulator, and I can't increase the voltage anyway, my little arrangement should give me a steady constant power supply, and a weight saving. If I use the 3.2ah battery.
panhead

That's the great thing about this forum panhead, we all learn things from each other that hopefully increases our chances out there in the field.
Cheers

Panhead my 6v batteries are rated at 12 amps at 20 hour discharge rate that is 72 watts capacity. Your 12 volt batt. is 3.2 amp that makes it about 38 watts capacity if the efficiency of your voltage reg is high you should get about half the running time of the standard batt. ie 4 hours or so. Best of luck mate.

Hi Panhead,

Sounds like your multimeter is working just fine. Might have to check to see what my car charger charges up to for curiosity sake. Its a good thing you don't have a wall charger(unless they improved them for the gp series) as the ones for the sd series, if you plugged them in and forgot about it, 2 days later you put the battery in the bin! Well that was my experience anyway.

Cheers Mick

My lack of a mains charger bothered me. But it was just one of those "I must get one someday" things. Coincidentaly, Aldi had one on special yesterday. $24.99. So I nipped down and got one. It charges/trickle charges 6v and 12v batteries. So now I've got the lot. Must try and go for a swing this week.
panhead

Gday Panhead,
If the 12vlt 3.4a/h gel battery dosent give you long enough running time,maybe upgrade to a 12vlt 5 a/h AGM battery. I sell them here for $35,so you should be able to pick one up for around the same price.

Fellas,
I always thought having a 12vlt battery regulated down to either 6.7 or 7.3 vlts would ensure your detector was running at full voltage all day.All 6vlt batteries are fully charged at 6.5 vlts.
MAXIMUM recharge voltage is 7.25 volts!
Standing surface voltage cannot be accurately measured until 48 hrs after charge,and should settle to about 6.35 vlts.

Gus,it is the batteries amp/hrs that determine how long a battery lasts under a specific laod.Your probably thinking because its a 12volt batt,regulated down to say 6.7 volts will almost double amp/hr usage but it don't.What actually happens is that regulated or not,a 12 volt battery quoted as having say 5Amp/hr running time,means it will run under load at 12 volts for a full 5hrs,nothing more nothing less.The missing 5.3 volts remaining(if regulated down to 6.7v),get dissipated in the form of heat through the componentry and heat sinks. For a 6 or 12 volt battery to run say 12 full hours under full working load,their Amp/Hr usage must be rated at 12 Amp/Hr.The only benefit as you say,is that the detector will run constantly on what ever regulated voltage you run through it,till it reaches the end of it's Amp/hr usage or cycle.

Cheers kon61.

I disagree Kon.
A 12vlt-7•2amp AGM battery will run( through a coiltek voltage regulator) a gp 3000 for up to 16 hrs from a full charge. I know because I ran one on a SD 2200,a GP Extreme and a 3000 for many years. 2 full days swinging from a full charge.
Your explanation states I should only get 7 hrs from a full charge.Remember that amp hrs are also measred at the Australian standard of a/h@ 20hrs @ 25°c,and no deep cycle battery will deliver its full amp hr rating.

Interesting Gus.I just don't recall ever getting 16 hrs on a full charge from a 12 volt 7.2amp,set on 6.7 or 7.3,but you could be right and I'm way off mark.It's been so long since I've used the 2.9kg 12v 7.2Amp/hr battery,that I've forgotten how many hrs running time I use to get on a 2200 or GP Series set on either voltages. First chance I get,I'll have to go back to the future and do some further re-testing with a new 12v 7.2Amp/hr gel cell and see what figures I come up with when regulated to 6.7v. I remember getting the 2 days or so running time without regulator from a 6v (4.5Amp max initial current) gell cell,but that was because the 6volt gell cell clearly stated(6V15Ah/20HR).Anyway it will be interesting to see what a 12v 7.2Amp/hr batt gives me in running time when regulated to 6.7 volts through my voltage regulator.Which comes to my next question,I wonder if there is a difference in volt/amp output draw,between one make of regulator and another?,for you clearly state "Coiltek Voltage Regulator",in which mine is not.Anyway I'll let you know what I come up with when I get the chance to put this theory through its practical test.And yes and I do agree that no deep cycle battery will deliver its full Amp/hr rating.

Cheers Kon.

I'm a little confussed too as as Kon previously stated, 5.3v (for the GP) would be "wasted" as heat across the heatsink whilst leaving the 6.7v to supply the detector. As a detector uses roughly 0.75A whilst working, then you would think that an 5a/h battery would last approx 6.6 hours. If you could run this 12v5a battery down to 6.7v without wasting the 5.3v across the heatsink, then you would get a much longer time, ie 12x5=60/6.7=8.95x0.75= 9.7 hours (if I've done my sums right). But, saying all that, I didn't think it was a possibility...
Cheers

Your sums are quite right Costas. 7.2 Amp/hr divided by 0.75A = 9.6 working hrs and that's about what I recall getting on my 2200 (between 9 to 10 hrs use).But once again,I do state,it's been quite some time since I had the old 12v 7.2 Amp/hr gel cell up and running.
Any body else out there wish to shed some light to this god forsaken situation of ours?

Cheers Kon.

Gday Kon & Costa,
Both your sums are correct,but it seems a voltage regulator pulls off a bit of magic somehow.
Its true the regulator heats up and perhaps sheds some voltage through this process,although minimal.
The biggest factor is if we are using a standard 6vlt-12a/h dome top battery, the surface voltage will shed within the first 3 hrs,leaving us running the detector at its minimal voltage for the remaining hrs.
Maybe the regulator can squeeze out more running time,even if the 12vlt unit has dropped to a flat reading of 8vlts? Im not sure and I may be wrong.
The only downside is the weight factor of the 12v-7.2. It dosent worry me because Im a big Unit,but to many others its a pain in the back.