GS 5 THRESHOLD PROBLEM

[waltr]

I had a closer look at the protection circuitry pcb from battery, it contains a chip marked 2158 which appears to be a monolithic step down switch mode converter. It's on a small pcb strip which could easily be taped on to another lithium battery.( Of comparable specs) This will protect battery from discharging below.

I must respectfully disagree that the chip marked 2158 is a step down converter. It does not make any sense to use that chip.
I am sure that the chip is a Voltage comparator and MOSFET switch specifically designed for Li-ion protection. There is a huge market for such a chip, millions of Li-ion batteries, so a chip with the needed functions would be designed and produced.

Here is the typical ciruit used:

https://www.digikey.com/en/maker/blogs/lithium-ion-cell-protection

Are there any other parts, chips on that protection board?
Can you please post a good photo of this protection board?

[Jose]

I would like to be able to know what the difference between GS5 and GS5C is. If someone can comment, I will be very grateful. José

[dbanner]

I had a closer look at the protection circuitry pcb from battery, it contains a chip marked 2158 which appears to be a monolithic step down switch mode converter. Not sure about what it's doing or even of it's function. Maybe this isn't protecting anything.? The datasheet gives output voltage of 1.2V@1 amp.

[daverave]

i think on a website like this which is open to the general public it can be difficult for some to post say like full schematics or even shots of classic detectors like GS 5 cause for one the material content belongs to the designer and not to any of us..most of us on this website make detectors for our own use but there are some from certain countries who will copy classic detectors to manufacture to make money which is very unfair for the designer of the product who will not benifit in any way from this...so i think its a very grey area so to speak.

[dbanner]

You are quite wrong Mr Banner. I have no objection to anyone who wants to 'pursue their own legitimate entrepreneurial ambitions'. If they wish to back engineer, trace out circuits, lay out pcb's, find alternate and sometimes better ways of doing things - no problem. Since the Goldscan 1 was introduced in 1982, there have been variations and improvements that culminated in GS5 in 2005. Further variations and improvements continued into 2008 (GS5C) when Whites purchased the design as a basis for the TDi. There are a lot of GS5's out there, as well as a host of earlier detectors, some of which will appear on the second hand market. All my designs are double sided pcb's, which are easy to copy and modify. There is no SMD GS5 as KT315 suggests. Why should I get involved with these activities, which take up considerable amounts of time, when I have my own 'entrepreneurial ambitions' in areas of further research? Just looking at posts on the Geotech Forum, the hobby/home experimenter/kit market is alive and well without my getting further involved.

Eric.

Mr. Foster, my comments were never intended for you or anyone on this particular thread, I want to be clear about that.
So please dispel any notion that I was making any reference to you. I have only the highest respect for you.
For clarity, I am referring to another thread which someone posted a pic of gs5 main pcb top side, but when asked if he could put pic of bottom side, went into convenient silence. As I recall, he claimed to have the main board on the workbench from which he took a hi res pic of top side. But somehow could not put pic of bottom side. Ha.

[Ferric Toes]

You are correct. MPP is derived from Eric's Minipulse( two stage preamp added, also some other small changes). But the PCB from silver dog is unique and original to the kit. As for gs5, mr. Foster is simply giving technical support for his own product.
But I personally don't have any knowledge of the fiduciary dealings made between various parties, nor do I care. I simply enjoy the kits offered for sale. People are entitled to pursue their own legitimate entrepreneurial ambitions If that is their pleasure. Perfectly ok by me.
KT315, you can read between the lines, you are smart person. Ask yourself why is there only pic of top side of gs5 pcb here on forum, but no bottom side?
It is just how it is. Different mindset between those who have, and those who have not. It is sanctimonious hypocrisy.

You are quite wrong Mr Banner. I have no objection to anyone who wants to 'pursue their own legitimate entrepreneurial ambitions'. If they wish to back engineer, trace out circuits, lay out pcb's, find alternate and sometimes better ways of doing things - no problem. Since the Goldscan 1 was introduced in 1982, there have been variations and improvements that culminated in GS5 in 2005. Further variations and improvements continued into 2008 (GS5C) when Whites purchased the design as a basis for the TDi. There are a lot of GS5's out there, as well as a host of earlier detectors, some of which will appear on the second hand market. All my designs are double sided pcb's, which are easy to copy and modify. There is no SMD GS5 as KT315 suggests. Why should I get involved with these activities, which take up considerable amounts of time, when I have my own 'entrepreneurial ambitions' in areas of further research? Just looking at posts on the Geotech Forum, the hobby/home experimenter/kit market is alive and well without my getting further involved.

Eric.

[daverave]

just been doing some research on the internet concerning li-ion discharge and it seems to vary according to the brand...but from what i can see most must not be discharged below 3 volts but some down to 2.7 volts...just hope i havent damaged any of my batteries.

[dbanner]

I just took apart an old lithium battery from Android phone. It was rated 2000mAh/7.4wh. very easy to remove the top of battery and there it was- a small pcb containing protection circuitry with label for b+ and b- . Easy hack. If you have these old batteries laying around,. Make use. But obviously test before using as it could be the reason why the battery failed in the first place. I think it's supposed to switch at 2.9 v for 3.7 v battery.

[kt315]

Hack old cell phone battery for protection circuitry board.
-------
Eddy smart buddy gives you a balansir for no money. http://smartelectronix.biz/publ/pros...orov/1-1-0-101
just take and use.

[kt315]

with two batts parrallel i do not need the protection board. i also charge them together in one time. my way is simplest way.
is nothing of reward difficulties on bare place.

[daverave]

Hi Dave, You are correct.
As the battery voltage falls, the converter will draw more current, which will cause the battery voltage fall faster and we have a runaway situation. There is a lot of information on the internet regarding the low voltage point for lithium batteries. This is particularly a point raised for radio controlled models. Some recommend getting the model in for a recharge when the battery is down to 3.5V per cell. My 2.9V even looks too low because as the battery is assumed to be under load, the voltage will fall fast. Cell damage will certainly have occurred at 2.5V. I have had this happen this myself and the battery cannot be recovered. They were not Chinese cheapos either. Whites battery packs for the TDi have inbuilt protective circuitry that prevents the voltage falling below the safe level. You can buy 18650 cells with protection, but the ones I have are longer and need a different battery holder.

Eric.

Hi Eric...i will have to be more careful in future with my li-ion batteries.....normally i discharge down to around 2.7 volts....i have got some protection circuits for the li-ion batteries which i bought from china some years ago but never used them due to them taking up space in the battery box...maybe a better idea is to buy the batteries with the built in protection but i think they are slightly longer due to be button top type cells.

[dbanner]

Hack old cell phone battery for protection circuitry board.

[dbanner]

MPP was been buy (put right verb form), copied and selling on silver dog site. is MPP NOT Eric's made detector?

You are correct. MPP is derived from Eric's Minipulse( two stage preamp added, also some other small changes). But the PCB from silver dog is unique and original to the kit. As for gs5, mr. Foster is simply giving technical support for his own product.
But I personally don't have any knowledge of the fiduciary dealings made between various parties, nor do I care. I simply enjoy the kits offered for sale. People are entitled to pursue their own legitimate entrepreneurial ambitions If that is their pleasure. Perfectly ok by me.
KT315, you can read between the lines, you are smart person. Ask yourself why is there only pic of top side of gs5 pcb here on forum, but no bottom side?
It is just how it is. Different mindset between those who have, and those who have not. It is sanctimonious hypocrisy.

[Ferric Toes]

Hi Eric...ive been the same and had no problems with noise whatsoever....to be honest i do prefer using straight battery power....i think it all depends on how light and compact you want to make the detector....but for high power detectors i think converters will drain the batteries much quicker....you mentioned about li-ion batteries failing below 2.9v volts...so if i risk discharging down to say 2.5v will i ruin the batteries ???

Hi Dave, You are correct.
As the battery voltage falls, the converter will draw more current, which will cause the battery voltage fall faster and we have a runaway situation. There is a lot of information on the internet regarding the low voltage point for lithium batteries. This is particularly a point raised for radio controlled models. Some recommend getting the model in for a recharge when the battery is down to 3.5V per cell. My 2.9V even looks too low because as the battery is assumed to be under load, the voltage will fall fast. Cell damage will certainly have occurred at 2.5V. I have had this happen this myself and the battery cannot be recovered. They were not Chinese cheapos either. Whites battery packs for the TDi have inbuilt protective circuitry that prevents the voltage falling below the safe level. You can buy 18650 cells with protection, but the ones I have are longer and need a different battery holder.

Eric.

[kt315]

MPP was been buy (put right verb form), copied and selling on silver dog site. is MPP NOT Eric's made detector?