power consumption

[Tibuck19]

Is it just mine or maybe my coils, But is your minipluse plus power hungry ? With 3 18650 fully charges I get about 3 hours max! of use time , as compared to my surfPi that does 8 hours easily, if not more with same 3 cells. I would also like to point out my Mini has the R7 and R8 mod which I started fiddling with from one coil to another, maybe my "fine turning" abilities or lack of, is causing drain ?

[Tibuck19]

George how can I delete a post after more then a half an hour?

This may help some or my not, Anyways here is what happen, After a little more then 3 hours of detecting the batteries had run dry which I thought was odd, but I did tune R 7 and R 8 to to match a spider coil I just made, (Which once tuned work ok! for a small 6 inch coil, I have no problems digging out 4 inch targets lol granted the been mostly pennies and bottle caps and I few nickels,) My problem was a combination of two things, sight over tuning the mosfet was little warm to the touch and out of 2 sets of 3 batteries I had two that were kaput. which isn't so bad considering they were used batteries out of old laptops and I had used them in many little projects as well as in my detectors, So after retuning and replacing the bad battery I started at 11.5V after one hour of detecting , I ended up at 11.4, so ten millivolts for one hour! that even better then I was getting with my 10 inch coil. If nothing I hope this post helps someone out in the future ! I hope im not cluttering up the forum !

[homefire]

Coil size should matter NOT . All your coils are going to have about the same resistance. Just for Chits and Grins run your battery leads through a Amp meter and see what it does pull . That would give you a fare gestimate on what your batteries should be able to do.

Running Idle.

Responding to Target.

[Qiaozhi]

George how can I delete a post after more then a half an hour?

I believe that the time allowed for editing a post is 1 hour.

[green]

Coil size should matter NOT . All your coils are going to have about the same resistance. Just for Chits and Grins run your battery leads through a Amp meter and see what it does pull . That would give you a fare gestimate on what your batteries should be able to do.

Running Idle.

Responding to Target.

I blew a fuse on my better meter trying to measure battery current. Short the test leads together to allow the large capacitor to charge when connecting the battery, then open leads to measure current. The circuit draws about 110ma, but I think charging the 2200uf capacitor caused the fast blow fuse to open.

[Tibuck19]

Im Pulling 0.20ma idle and from 0.20ma to 0.26ma when I swing something over the coil and up to 0.29ma with a big pair of wire snips. SO if my math is right ( lol which im sure its not hahah ) my 18650 I think are 2200 / 0.23= 9.5 hours on a charge ?? or does the fact are that they are in series change anything ?

[Tibuck19]

I believe that the time allowed for editing a post is 1 hour.

Thank you , I will try not to clutter the forum with my beginner questions Esp the fact I solve them myself in mean time . I sure the Aim of geotech is to share ideas and concepts , not I a metal detectors for dummies

[homefire]

LOL, You should see some of the Doozies I've Posted.

[Tibuck19]

LOL, You should see some of the Doozies I've Posted.

im sure they can't be any worst then what I come up with lol but thank you for the sympathy.

[Tibuck19]

I believe that the time allowed for editing a post is 1 hour.

Good evening , What is the Max voltage I can use the minipulse at? Right now im using 3 18650 which give around 3.8 V = 11.4 ish, if I use 4 that will bring me up to 15.2 Would it make a difference , Because again from 11.4V I hunted only 2 hours and it drop to 7.45V granted I picked up a lot of trash nails and bolts and such, I could swear I was getting longer use time with my ten inch Mono loop, then I do with a 6 inch spider coil.

[green]

Good evening , What is the Max voltage I can use the minipulse at? Right now im using 3 18650 which give around 3.8 V = 11.4 ish, if I use 4 that will bring me up to 15.2 Would it make a difference , Because again from 11.4V I hunted only 2 hours and it drop to 7.45V granted I picked up a lot of trash nails and bolts and such, I could swear I was getting longer use time with my ten inch Mono loop, then I do with a 6 inch spider coil.

What brand battery are you using? There has been a few threads discussing poor quality of some brands.

[Tibuck19]

What brand battery are you using? There has been a few threads discussing poor quality of some brands.

They are Samsung, I know they are good because I use them in the surf Pi and they last for 8 plus hours on a single charge. I first I though I had 2 of them were kaput out of the gang I have but after giving them a full charge they seem ok. but those were not the once I used this evening.

[Qiaozhi]

Good evening , What is the Max voltage I can use the minipulse at? Right now im using 3 18650 which give around 3.8 V = 11.4 ish, if I use 4 that will bring me up to 15.2 Would it make a difference , Because again from 11.4V I hunted only 2 hours and it drop to 7.45V granted I picked up a lot of trash nails and bolts and such, I could swear I was getting longer use time with my ten inch Mono loop, then I do with a 6 inch spider coil.

The upper operating voltage for the LT1054 (which will be the limiting factor) is quoted as 15V, but the absolute maximum supply voltage is actually 16V. In that case you should probably be ok at 15.2V, as I suspect that is the open-circuit (no load) voltage on the battery, and this will drop at bit when under load.

[Tibuck19]

The upper operating voltage for the LT1054 (which will be the limiting factor) is quoted as 15V, but the absolute maximum supply voltage is actually 16V. In that case you should probably be ok at 15.2V, as I suspect that is the open-circuit (no load) voltage on the battery, and this will drop at bit when under load.

where you guys having a debate about the LT1054 vs 7660 chip, you seem confident the 1054 was the better one. BTW when I replaced the 79L05, I replaced it with MC79L05BP which on the data sheet says it a fixed output of -5 100ma, Do you think that might be the source of my power drain ?

[Qiaozhi]

where you guys having a debate about the LT1054 vs 7660 chip, you seem confident the 1054 was the better one. BTW when I replaced the 79L05, I replaced it with MC79L05BP which on the data sheet says it a fixed output of -5 100ma, Do you think that might be the source of my power drain ?

What that means is that the maximum current it can supply is 100mA, not that it always consumes 100mA. The "fixed output" refers to the voltage.