Battery level vs. Performance

[squeak16]

Does anyone know if there is a drop in detector performance as the battery level goes down?

 

[INSAYN]

I haven't noticed any until it is just about to die.

Tones get weak and kind of fluttery in the last 10-20 minutes of battery life.

 

[squeak16]

thanks for the feedback, wasn't sure what to expect, battery seems to last pretty good, WM10 not sure what will happen, i'll plan to charge same time as detector

thanks
Philip

 

[INSAYN]

Don't remember ever having the WM10 dieing before the detector battery.

I usually recharge both together regardless, and well after 8-10 hours of detecting time.

 

[Digger]

The detector regulates the output voltage so that its performance remains constant regardless of the charge remaining in the batteries. The 5-segment battery icon on the screen displays the amount of voltage available in the battery. As the voltage in the battery diminishes, the segments go away. When the last battery segment disappears, an empty battery" message appears on the screen, and you will hear a tone about every 20 seconds. When the battery level is unable to provide sufficient voltage to the detector, it turns itself off. HH Randy

[attachment 289860 batteryinfo.jpg]

 

[squeak16]

thanks digger, I was nervous about this machine, being complicated, but with advice and the great videos and the training search modes all made it quite smooth

 

[Johnnyanglo]

You may find, if you use the Grey Ghost headphones, that if the voltage drops sufficiently then the headphones shut off. The internal speaker will still work. I've had that problem when using semi-drained batteries - the headphones cut off but the detector can still operate.

 

[AngelicStorm]

The detector regulates the output voltage so that its performance remains constant regardless of the charge remaining in the batteries. The 5-segment battery icon on the screen displays the amount of voltage available in the battery. As the voltage in the battery diminishes, the segments go away. When the last battery segment disappears, an empty battery" message appears on the screen, and you will hear a tone about every 20 seconds. When the battery level is unable to provide sufficient voltage to the detector, it turns itself off. HH Randy

[attachment 289860 batteryinfo.jpg]

Is this true for 2,500 mAH rechargeable NiMH batteries? I recently purchased eight 2,500 mAH batteries for my Canon 150is camera due to the camera needing higher capacity batteries to run properly and they have made a drastic difference. From what I understand the average rechargeable batteries are 1,300-1,700 mAH.

Good these batteries they have 1,500 cycles. That means I can go out detecting with them 1,500(Higher Performance)=Better Finds if what you said is false for higher capacity batteries.

 

[Digger]

I don't mean to bore you. But in regard to voltage, amperage and resistance........ the replaceable cell pack takes eight AA cells. You can use eight 1.5 volt alkaline, eight 1.2 volt rechargeable NiCd or eight 1.2 volt NiMH cells. These cells connected in series comprise the battery. Regardless of whether you start out with eight alkalines with a total output of 12 volts ( 8 X 1.5) or eight rechargeable NiCd or NiMH with a total voltage of 9.6 volts ( 8 X 1.2), the voltage applied to the electronics is constant, due to the voltage regulator in the CTX 3030. Voltage is the "electrical pressure" placed on electron flow within the CTX3030. The current that flows is measured in amps. One milli amp (mA) is one one-thousandths of an amp. One amp per hour = 1000 mAh. Amp hours (or mAh) represents how long a battery can deliver a certain amount of charge before it runs out. The opposition to the flow of electrons is resistance. In this example,resistance is the electronics of the CTX 3030. So if the voltage is regulated, and the resistance is constant, the measurement of mAh ( you said yours were 2500 mAh) will determine how long your CTX 3030 will operate, without having to recharge the cells. The higher the number.....the longer it will operate. HH Randy

 

[AngelicStorm]

So say the stock ctx rechargeable battery pack is running at 9.6v and xxxx mAH, would my 2,500 mAH or 2.5 amp per hour 1.2v batteries x8 last just as long or longer than the stock rechargeable "battery"? What are the specifics of the stock battery? I have noticed that starting off on a full charge the CTX will keep going for about 12-14 hours. Also, staying in that range (9.6v - 12v) the voltage regulator must do a good job of protecting the circuitry from overload "erractic responsiveness" or rather surging. If exceeding the 12v threshold I imagine that maybe the regulator would "leak" out excess voltage causing less resistance due to less opposition from the electronics.

Thanks Digger. Information that is very useful as always and well taken.

 

[Chris(SoCenWI)]

Digger,

It is true that higher Mah will run longer, but with standard NiMH cells the cells will self-discharge even when you are not using the detector. I've been using the low self discharge versions that run down much much slower when not in use. I find for my style of detecting- two three hours here and there- that a pack of these can last for several detecting sessions, and will stay pretty much fully charged for a year or so. I was recharging the higher Mah style much more frequently because they would go dead just sitting around.

 

[laplander]

I have personally found great finds just minutes before the detector shut down. I don't normally push the battery life envelope but I am having issues with a recharging station (minelab) and thought I was starting with a fully recharged batttery Luckily I had the backup and minelab is replacing the faulty unit 10 plus hours from both the wm 10 and the factory rechargeable is norm for me.

 

[Digger]

You are correct. I was basing my response to the maximum mAh capable of being charged. As you noted, various technology offers "longer" storage capabilities. According to the manual, the Li-Ion pack that is available for the CTX will last up to 13 hours, without recharging. NiMH or NiCd batteries are more along the line of 7+ hours. For those interested.......alkaline AA batteries have a mAh rating ranging from 1500 - 3000 mAh. But as many of us have found out when replacing batteries in our smoke detectors...those spare alkaline batteries sitting in the closet won't always be as fresh as you had hoped. HH Randy

 

[Digger]

Don't let the terminology of cell vs battery be confusing. A battery can be a single cell, or a group of single cells connected in either parallell or series. If you connect two 1.2 volt cells in series, the total voltage is 2.4 volts. If you connect them in parallel, the voltage is still just 1.2 volts...but they will "last" twice as long. Examples of a single cell could be an AA alkaline, NiMH or NiCd. When we place those cells in a battery compartment, they become the battery. Individually, however, they are simply cells within that battery. As an example, if you had a flashlight that took two AA cells, those two AA cells are the battery. If you had a flashlight that took only one AA cell, that one AA cell is the battery.

To answer your question "would my 2,500 mAH or 2.5 amp per hour 1.2v batteries x8 last just as long or longer than the stock rechargeable "battery"........I doubt it, because of the maximim capacity of the initial "full" charge. What I have seen is that the Li-Ion pack and AA alkalines will allow the battery icon to show a full charge. From my limited experience using NiCd or NiMH cell packs, they do not. That would indicate to me that the "meter" that controls the number of bars in the battery indicator is capable of measuring 12 volts. Since we know the 8 AA alkalines total 12 volts, that seems logical. Since the NiMH and NiCd batteries only allow for a full charge of 9.6 volts, it won't fill up the bars in the indicator, even when fully charged. Lithium Ion batteries are a different breed of cat. I don't know how many cells are used to make up the LI-Ion pack in the CTX3030. I would guess it is three, based on the battery indicator showing a full charge with the Li-Ion and AA alkalines. And, a Lithium-ion is charged at approximately 4.2 volts......+/- 0.05 volts. This would indicate that a fully charged Li-Ion Battery pack would be at about 12.6 volts. But again, with the voltage regulator, this slightly higher voltage is irrelevant. In addition, NiMH cells each having 1.2 volts doesn't mean the detector is pushing electrons at a voltage of 9.6 volts. It just means that there are 9.6 volts available to push those electrons. Again, the voltage regulator "limits" the amount of voltage put to use. If someone felt compelled to take it apart to measure the current flow through the electronics, we could learn how many milliamps the CTX 3030 requires. If we knew that, along with the resistance of the electronics, we could mathematically figure out how much voltage is required to push those electrons through the detector. JMHO HH Randy

 

[AngelicStorm]

Thanks Digger.

Your statement "And, a Lithium-ion is charged at approximately 4.2 volts......+/- 0.05 volts. This would indicate that a fully charged Li-Ion Battery pack would be at about 12.6 volts. But again, with the voltage regulator, this slightly higher voltage is irrelevant." This must mean there is a .6v surplus available, an indication to why the battery icon reads full for a longer time before dwindling down faster than the first x amount of time the battery icon indicates a full charge. Maybe using NiCd or NiMH batteries with 9.6v presents the same problem I had with my Canon 150is camera where the 1,300 mAH batteries I was using only gave it a charge that would last maybe five minutes versus the mentioned 2,500 mAH batteries that now give the camera a 2-3 hour charge. With that being said to put it simple considering what has been said, using rechargeable batteries with a voltage of 9.6v/8 per cell would have negative effects as the stock battery is probably more energy efficient due to the voltage regulator and a higher mAH.

It would be great if someone took apart a CTX 3030 and measured the current flow and resistance of the electronics like you said. Imagine the possibilites if we could control the current flow to our benefit without over doing it.

 

[mcb613]

From an electronics standpoint Digger has it correct. The beauty of ICs!

 

[Digger]

Imagine the possibilites if we could control the current flow to our benefit without over doing it.

If we were to connect multiple AA battery packs in parallel, and fill them up with whatever mAh batteries you chose, the voltage would still be the same as one battery pack by itself. But if we strapped enough of them together..(tongue in cheek)........we could hunt for days! Maybe even weeks! Depending on how "big" we wanted to go, we might need a wheelbarrow to carry them around. HH Randy

 

[BchPatrol]

This thread made me curious about the actual capacity(mAh) of the Lithium-ion battery pack. I assumed that this would be easy to find but I was wrong. The ML site provided no clues and google didn't find anything either.

 

[mcb613]

I always use the AA pack. Never tried the Lithium, if that's what it is. I know Lithium powered tools dont work well in cold temps and shut off abruptly. Wouldnt want that !