Question on power draw ?

[amberjack]

Just wondering if anyone knows what sort of amps the CTX would draw on the battery pack, and how regulated the detector is? I know the li ion pack is 7.2 volts , so 8 AA's at full charge 12 volts, 8 x AA rechargables is 9.6 volts.

so obviously its regulated but what I am looking to find out is the amp draw if anyone knows help would be very kool

just on a side note has anyone experienced differences in performance using the li ion pack to AA recharables?

cheers for the help!!

AJ

 

[Jason in Enid]

I'm sure somebody with more electrical experience than moi can answer this question. I'm sure there are factors such as backlight on, GPS, etc.... but you can look at the starting voltage and amps of the battery pack, then do some math with how many hours of use before it dies to calculate the power draw.

 

[amberjack]

yes some quick maths, as the battery is in watt hours not amp hrs, so conversion is about 26 amp hrs and the manual says 13hrs run time? so that would be about a 2 amp draw all things being equal, I am not an expert so if I am wrong

my battery pack died 12 months ago and wasn't paying the 150 for a new one with 3 cheap chinese li ion batteries in there although I might put some high quality ones in there, but in the mean time I am running rechargables in the other pack and just wondering if anyone knows how the ctx is regulated really on its power supply.

I was reading somewhere that some gpz guys could run the ctx li ion battery but the AA pack wouldn't work on the gpz was going to suggest they try some 1450 li ion batteries in the AA pack they are 3.7 volts or 4.2 fully charged might get them up and running if out in the field and the other one runs out. but if you read this its your risk I am offering an option and not advice.

but I digress really the ctx has to be regulated internally I know the li ion batt has a circuit board but the AA doesn't so it has to be inside so what amps is it drawing and what voltage is it running at so if its 2 amps draw, still that's a rough calculation.

so why am going on about this ??

I want to know I am getting full power to the coil and beyond with the AA pack there are a few battery options and if I have all the facts I can make the best choice in batteries to run in the AA pack.

confusing yes but only because I don't have all the facts and I don't work for minelab and well we all know what they give out in regards to this type of information

I have more chance of finding a saxon hoard in Australia

why am I asking this/these questions I had my eye on some 1.5 volt lithium polymer rechargeables AA size but if its pulling 2 amps they will get hot and I don't want that.

I know I put some nizn batteries in a etrac 1.6 volts AA size and it wouldn't fire up , but maybe they are worth a try on the ctx but again what's happening inside regarding voltage regulation??

thanks again !!

AJ

edited to add more info and fix some facts and spelling.

 

[Jason in Enid]

Yes, it has an internal voltage regulator. The small PC board on the factory recharge pack is probably to help control the recharge process and prevent overcharging. The internal regulator is controling the volts. The detector needs less than the batteries supply when full. I don't have the exact numbers, but for example.... a fully charged batt pack has 14 volts, yet the detector is only letting 8 volts come through. It continues letting 8 volts in to operate everything until the batteries drain down. Once the batteries can no longer supply 8 volts, the machine turns itsself off. This way you get the same performance every minute of operation. MOST detector are designed this way, although one of the excal experts has said that machine does NOT have the limiter, so you could actually get better performance at the start compared the end (but I digress)

 

[amberjack]

went ahead and repacked the li ion battery pack with some laptop 18650's I am no electrician but all I needed was a star screwdriver sure they have a name its like a hex head but a star shape to pull the thing apart, some small dismembering tools for the crimped on strapping and went to putting the new 18650's in what got me started was seeing someone is selling etrac li ion battery packs for 140 bucks so anyway its back together and on the charger and charging nothing weird has happened touch wood sorry for the poor photos its was a 1 am job with a headlight on

so fingers crossed for a new battery pack

still charging so time will tell right

bit of fun with nothing else much to do ! took me about an hr.

AJ

 

[amberjack]

here's an update the batteries charged to full 2 green lights and give me a full green bar on the detector, only thing now is how long will they last, considering they are Sony made in japan batteries and not cheap minmax Chinese cells like in the original pack my hopes are high, so when your pack fails and it will this is a pretty easy fix.

so far so good, I was only getting 3/4 bar on the AA rechargeables and was thinking maybe I am not getting full power to the coil probably am but don't know for sure 100% so all in all a good outcome and I am happy and saved myself 150 so a good day

I put this up for anyone who might have the same problem and so they know there is a fix.

AJ

 

[amberjack]

these are the ones that come out of it as in the minelab ones.

about the only thing I could find on them , minmax


my bad the batterys I put in made in Japan Panasonics plenty of info on them.Panasonics

and that's about the end of the story hope it may have helped someone, if not it helped me and I hope to get a few years of trouble free detecting out of my new pack

AJ

 

[J.D]

HI AJ this is a fantastic post..thanks for sharing ..id love to see someone do a similar mod for the etrac aswell

 

[amberjack]

thanks J.D check this out http://www.findmall.com/read.php?63,1817505

12.5 volts would be the cut off point I think on the etrac so the charger is key I think with the cut off at 12.5 volts so at least you have the numbers to work with sure you will work one out to fit in the etrac pack run 3 batts end to end would work I recon !!

AJ

 

[J.D]

Thank you kindly for the link AJ your a helpfull guy ...let us know how long they last...i also have some lion batteries lying around after reading this post i am also contemplating on making a battery for my etrac...thanks AJ

 

[amberjack]

no worrys JD glad I could help sounds like a good plan making a pack for the etrac, sure you will make a good one !!

I will report back in time on how the new pack lasts sure it will work great !

all part of the fun hey, I learnt something from the whole exercise in that it wasn't that hard

let us know how you go with the etrac.

AJ

 

[DaveMcC]

Very useful info Amberjack. Thank You.

 

[amberjack]

no probs Dave glad it could help.

most of these packs will be not far off packing it in pardon the pun

so 4 x 18650's from Sony, Panasonic, Samsung are going to cost about not to much depending on mah and an hours work and you got a pack that's going to last several years, and save some $$$ so I am happy I opened her up, bit of a battery junkie go for the brand names fasttech stock good batteries at good price. https://www.fasttech.com/category/1420/batteries

have dealt with them to many times torches oh dear but they are fun !! anyway never had an dramas with getting my order.

the ones that come out are 65 mm so wouldn't go much bigger as the sizes do vary.

think that's about it other than my pack is doing great

AJ

 

[Digger]

[attachment 312602 batteriesvoltage.jpg]

 

[Digger]

[attachment 312603 batteryoutputvoltageandcapacity.jpg]

 

[amberjack]

thanks Digger good info , recon I have enough rechargeable AA's and my repacked Li Ion pack to last me how long battery addiction

went for a spin this morning 6" coil as you can see got tricked by a couple bits of iron or I was over zealous

oldest 1921 threepence, so 4 silver, 1/2 doz penny's ...

good few hrs. where I'm at

AJ

 

[N7XW]

Great thread, following...

 

[AngerManagement]

Just a reminder - Not always about Voltage...

Depending on the way the system works it is a combination of Voltage and Current - And a battery with High impedance may measure OK but unable to supply the current.

Not as simple as that - but KISS is a good start.

Also measuring Batteries with no load can give you the wrong impression and some systems take a SURGE at start up... And a system can fail at that point, even though the batteries might seem ok, even under a load test.


As to AA's They are all different and it is often one or two of the 8 in the pack that fail... So a few spare and a DVM can get you over a hump...

 

[IDXMonster]

Also consider(if you haven't) that running no disc will eat batteries faster than running high disc as the speaker or headphones are being driven a lot more. I'm not trying to overstate the possibly obvious....

 

[Goldleaf]

Can't view photos of your April 18, 2015 posts.
Any way possible to direct me to where I can view them?
(I'm needing to operate on my un-revivable CTX battery)