Batteries

[Max]

Hi,
Max.
when I use this ac/dc adapther with scale 350ma max when I turn trimer I get from 11 to 12,8V.With other from cellphone charger I get from 12 to 13,5!
Thanks
can you tell me your opinion about this scope C1-68 1Mhz?Is it worth to buy this one?45 euros!
I just went back from a new fortress,from one side the snow were gone and I try to detect.I found 2 small thin pieces from some aloy/modern/,but I think that I get one coin in some leaves!I think no more than 2 cm but it were close to one tree.So its look like I have nulled my coil good?
Thanks

Hi,
about coil I think you nulled well, so you start finding stuff, no matter if modern or ancient... now you can say your TGS actually works on soil.
About scope... well is fairly cheap stuff: 1MHz is more than enough to null coil, but look at minimum voltage you can measure (e.g. 5mV/div) to know if has enough amplification for fine work on nulling coils.

For other stuff 1MHz BW is too limited and you cannot use... but of course if you plan to find faults on TGS and null coils I think is good.

PS: you need higher voltage power supply for charger... it must reach the 14V output easy without load

Best regards,
Max

[tiktak]

hi

Hi,
Max.
when I use this ac/dc adapther with scale 350ma max when I turn trimer I get from 11 to 12,8V.With other from cellphone charger I get from 12 to 13,5!
Thanks
can you tell me your opinion about this scope C1-68 1Mhz?Is it worth to buy this one?45 euros!
I just went back from a new fortress,from one side the snow were gone and I try to detect.I found 2 small thin pieces from some aloy/modern/,but I think that I get one coin in some leaves!I think no more than 2 cm but it were close to one tree.So its look like I have nulled my coil good?
Thanks

[Max]

Hi,
I see, this also work pretty nice... I have 3 of them and use with different lead-acid sealed batteries (1.2, 1.3 and 2.2 Ah... but I have used also with 4Ah battery and always worked OK)

You have to just regulate the trimpot to change output voltage; resistor value change is required only to limit initial current: you can also leave 2.2ohm... don't worry about it at now.

Check if moving trimpot you reach 13.8V for now and let me know.

Best regards,
Max

[tiktak]

Hi

Hi,
Max.
No I talk about this second circuit with LM317T and one TR,led diode,......its here on page one.

[Max]

Hi,
Max.
I have made this circuit for charging today but have a couple of questions.
When I conect to power with no load the led diode is flashing and the voltage at end is 13,45 MAX.!!!???Is my ac/dc adapter week or what?
Where should I conect this ground spot under led diode?To - line?Because I have conected it now directly where ac/dc - wire reach its place on PCB.Is that right?
Thanks
p.s and this tr is with c b e pin configuration right?
Because I dont think that the probleme is in TR.

Hi,
do you mean the LM317 circuit I've posted ?

If so, it's regulator ic not transistor... you must be careful with pin assignment and don't make wrong connections to it...

I've used that circuit for a very long time and made many similar all with good results... don't know why you experience problems with it. Your transformer will give enough ac at input of bridge (usually 14Vac are enough... but you can use 16-18Vac too). If don't use rectifier bridge (so using DC output of a power supply) you need at least 16-18Vdc for right operations cause of dropout of regulator and other factors.

Best regards,
Max

[tiktak]

Hi

I have used 4,7 ohm resistor insteed of 2,2 like you say!
If I change this with 2,2 wont the voltage rise to 13,8 like it should be?
Thanks

[tiktak]

Hi

Hi,
Max.
I have made this circuit for charging today but have a couple of questions.
When I conect to power with no load the led diode is flashing and the voltage at end is 13,45 MAX.!!!???Is my ac/dc adapter week or what?
Where should I conect this ground spot under led diode?To - line?Because I have conected it now directly where ac/dc - wire reach its place on PCB.Is that right?
Thanks
p.s and this tr is with c b e pin configuration right?
Because I dont think that the probleme is in TR.

[Fred]

Hi Tiktak,

when it reaches 12,5v wait more half an hour or 1 hour and its done.
Fred.

[tiktak]

Hi,

Hi,
fred
for how long should I charge?Now the battery shows 11.04V?
How can I calculate?
Thanks

[tiktak]

Hi

Hi,
How should I understand this 1-2 hours;3-4hours???
I am stupid and used this new battery.Damn...............
Hope that haven't damaged it much?
Thanks

[Fred]

BTW, its not good o use battery from factory, first thing to do is to fully charge it.
regards,
Fred.

[Fred]

It depends of how deeply discharged is your battery, but a few hours should be OK : connect your ammeter and check how many mA it takes, then you should easily calculate of how many hours you need.Keep in mind charge rate will decrease with time,its not linear,and at the first minutes it will be much more .dont take this in your calculations.
regards,
Fred.

[tiktak]

Hi

If i were you , i would just connnect the adaptor to the battery, just to be sure check temperature of battery and adaptor for the first hour, and dont worry more.
Of course it is not the academic way to do it, but in practice you will have good resuts.And we all do this but dont want to tell
Those adaptors are not regulated,this is why you get 16V, there is capacitors inside that charges when there is no load.
go for it!
Fred.

Hi,
What do you think for how wong should I charge with this AC/DC adaptor only?
Thanks

[Qiaozhi]

If you're worried about excessive charging current with a 16V supply, then simply put a 20 ohm resistor in the line. This will limit the charging current to the maximum allowable 350mA, even when the battery voltage has dropped to 9V.
However, you are still better off to get one of these ->
http://www.maplin.co.uk/Module.aspx?...arger&doy=7m11
The LED starts to flash when the battery is fully charged, and there is no danger of overcharging.

[Fred]

If i were you , i would just connnect the adaptor to the battery, just to be sure check temperature of battery and adaptor for the first hour, and dont worry more.
Of course it is not the academic way to do it, but in practice you will have good resuts.And we all do this but dont want to tell
Those adaptors are not regulated,this is why you get 16V, there is capacitors inside that charges when there is no load.
go for it!
Fred.