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[Goose]

O K battery people, what's the scoop? I have a DFX and after 2-1/2 yrs the original rechargeable battery died. I purchased a used one from the net and it's been going great guns now for 6-1/2 yrs. I have never and will never use the "Quick" charge....just my preference.

When my present battery runs down to 8.7, I recharge it for 6 hrs....then it shows 11.3. The other day, it ran down and I charged it only for 3 hrs, (I wanted to get out to detect) and it showed 11.3....good. What I'm wondering is, is there sort of a 'surface' charge in the battery that might discharge more rapidly than a normal long "Overnight" (slow) charge? The manual says that an "Overnight" charge takes 'as little as 14 hrs' to bring it to a full charge. Does the "Overnight" charge (12+ hrs) seem to last longer than a short 3 hr charge? I don't know.....I only have 5 hrs on that short 3 hr charge and the battery reading is at 10.3....not too bad.

[tr snyper]

Goose - You probably can guess what I'm going to say but I only get on this site once in a while now so I have to say something

Batteries shouldn't really be quick charged in my opinion. They need to charge slow. Slower then the rate the detector can use the power at the least. When you charge a battery (remember I am no engineer for sure) the process causes reactions in the electrolyte to electrify them to be able to put out a charge. And quick charging, from what I had heard heats the molecules to quick enabling it to fully charge. It may read 12v but it sure won't stay long. Yeah that was a bad explanation I just don't know how to explain it.

Did you ever grab a flashlight for something and it turned on nice but in two minutes it dies. That's why I quit using re-charge's. You can't really predict how it will hold up. After it charged and yours read "11.3" how long did it take to hit the 10v range? Now that's just reading the voltage only? There is no load on the battery yet! It doesn't know what program you are going to use! What is the voltage dropping to when the AC and DC are on, and the tracking is thinking and it's balancing all the time, then the disc is reading signals, and the screen is drawing power and the speaker ect. etc. etc...

At the DFX Tuscazoar hunt I charged my battery slow over night after wearing it down to 9.7. It read "good" well I don't remember the number but I wouldn't have used it if it didn't. I can't remember the number exactly. Any way I walked the site for maybe 3 hours swinging with it on. I wasn't hunting I was flagging sites. When I just decided to start this one site I didn't look at the reading I just started hunting. I hit a nickle then I hit a Scout's pocket knife. I got up and I could tell I was having a problem. I read the ground and checked everything then within the static I hit a Buffalo??? Now at this time other hunters were pulling big silver all around me. I shut the machine off put it on the ground smoked a cigarette and drank a beer to re-boot what I thought was me. When I went to start again I saw the battery flashing 7-8 and turned itself off. Twice! I never used a re-charge again and wouldn't consider it.

Alkaline batteries sometimes read 13+ volts and they drain very slow BUT better yet consistently. I know that the machine is designed to run on 8+ volts. But I swear that I can notice a difference when it gets in the mid 9's. On new batteries it takes me over a week to drop below 11v. And at least two more to drop to around 10.2-10.4 which is when I'll change them. But the best thing is if I turn it on "say at 10.2v" I can hunt for the day and right after I turn it off I can turn it on and the power will be at least 10v. The recharges will drop much faster and kind of have to take a break to build up a little. And it's the unpredictable slide down that I don't like.

Maybe this is a good example. You know how your house is running on 120/240. And if power surges you can trip a breaker over heating the circuit. Well this shouldn't happen to a detector but what happens when it's not a surge but an overload draw on the system. The power grid. It drops power for a second. We barely know it but the lights may dim a little or blink. Because the voltage may be there but the kick from the Amp's aren't.

What I guess I'm saying is, I worry while running hot with the machine that I don't know where the power is at with re-charges. The Alkalines will drain at a steady rate where as the recharge can bounce up and down while draining down, and I wouldn't know it happened. So does the detector dim or blink also? If so I wouldn't want it to blink when it's over a target that is already hard to hit. Or momentarily drop the tracking. Maybe I am over thinking but I buy the batteries in quantities where it costs about 10 bucks to run a set. I can get near a month and I log some serious hours on my machines. And half the time with the light on using the DFX. Plus being I use a BHID equally I can always have reliable packs ready at anytime for both detectors being they have the same batteries. I could imagine how many times that I would have to recharge them. Even at every three days that's 10 charges in the month. Per machine. So actually I would spend a lot of time charging back and forth. And the BHID is a project because it's in a chest mount harness. Then how much does it cost in electricity to charge these batteries properly? Then when I take the old ones out they still run flashlights and channel changers since they aren't even dead yet.

I guess most people don't have the time I am lucky enough to have to hunt as much as I do and the re-charge may seem better or be more economical for them. But to me the time alone isn't worth it. ESPECIALLY when you forget to re charge it and you get a chance to hunt a spot you weren't expecting and you have to do it at that moment. At any time I know the machine is ready and I won't stress it dropping power.

Think about this. Would you rather have someone give you $10.00 every hour for 3 hours. Or $3.00 every hour for 14 hours. Well the battery can only be forced to take so much with in a short time. As opposed to be able to handle much more easily over a longer period of time?
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better to search and fail then never search at all

[Goose]

TR S, I was just curious about a short "Overnight" (3 hrs) charge. I never used the "Quick" charge and never will as I mentioned above. Since I had a hunch that a "Quick" charge would possibly shorten the battery's life, I cut a little itty bitty piece of palstic and put it in at the recharger's Quick/Overnight switch with the "Overnight" switch always on. Then I just taped the plastic in place. I will never have problems with a wrong charge.

As for alkaline batteries, I have my extra battery pack loaded with them but I haven't used the pack yet....in 9 yrs. I get off-brand alkaline batteries for $7 for a pack of 24..... to me, a good deal.

[ernie46]

I really like using the lithium batteries when I'm going on a long day hunt. they start at 13 plus volts and only drop to just over 11 after a full day. They are quite expensive though. My local Lowes has off brand alkies at $20 for 100. Haven't tried them out yet, but that seems a real bargain.

[tr snyper]

When I was saying how much the batteries cost I screwed up. I don't know what I was thinking. I was rattled a little about a different post. Anyway. On sale I get the Kodak digital alkiline AA's for $1.24 per 4 pack if I buy 4 packs. But there is a 4 pack limit. So I get 4 and my sweetheart gets me 4. So for about $10.00 ($9.92) I get 8 packs of 4 batteries 32 batteries. I somehow was thinking 8 batteries yesterday and not 8 packs. So to load the detectors pack I spend $2.48 (plus tax) for 8 batteries. 10 bucks fills 4 battery packs. Not 1!!!

Even if I really run the detector very heavy for three weeks straight the voltage doesn't drop below 10.2-10.4. For $2.50? The electricity has to cost something plus there is a lot of time lost involved with charging the pack that much. I can't forget to do it and I know the power won't drop out on them unexpectedly. The clad pays for them anyway.
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better to search and fail then never search at all

[V-tail]

You assumption is correct regarding a "surface" type charge that brings the battery pack to 11.3 volts in a short amount of time. You are also correct regarding the limited capacity that the pack will have if you only charge it at the overnight rate for 3 hours versus 14 hours. This is because at the overnight rate, it requires the extra time to reform the batteries to maximum capacity.

The Whites battery charger that comes with the DFX is not a "smart" charger and simply puts out 11.6 vdc at one of two charging rates (85mA=overnight rate; 280mA=fast rate). The NiCads in the OEM rechargable pack typically have a capacity somewhere between 500 to 1100mA per cell (8 cells in the pack). The problem with charging at the fast rate, as you and tr snyper probably already know, is that it has the potential to overheat the cells and cause damage to them physically and chemically, consequently impeding their ability to reform during the charging process. The resulting damage limits their future capacity.

So.. the short answer is (if you can call it that): if you recharge your pack for 3 hours (at the overnight rate), you will still see 11.3+ vdc when you power-up but your hunting time will be limited. (Also, by not fully recharging the NiCads, you risk limiting their future capacity because they have not fully reformed internally.) And.. don't use fast charge if you can help it because you have a higher risk of damaging the batteries.

Hope this helps.

[tr snyper]

V-tail - I didn't know what the mA revovery rate was so I tried to compare it to money. Everyone relates to that! I didn't know the actual rate you had posted. That's even worse then I had thought. What is another bad thing is that the detector doesn't drain enough to actually truly charge it effieciently. When you use cordless tools you charge when they can't perform. But the detector doesn't pull it down enough. So the re-charge process can actually "cook" good "chargered" electrolyte per-say! Then it becomes like spent car oil. It will never be what it ever was and you won't know until it fails you! And it dies right then!

I notice even when I store the machine for any period of time the power stays there. In the re-charge I would notice a drop in the power. And it would drop off quick if I hunted with it.


I guess it bothered me that day because I drove 950 miles, slow charged it in a hotel over night and it "quits" on me in 3 hours. On top of a hot spot. But the Kodaks saved the weekend.

I'm sold on the Kodak digital alkiline AA's. When I get new machines I give the re-charges away
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better to search and fail then never search at all

[V-tail]

tr snyper- I've experienced the same thing with my rechargable NiCads and I can relate to the long distance hunting trip only to have the batteries fail shortly after the hunt began. My NiCad pack lasted about 3 years before it started showing signs of limited capacity. I tried the various tricks I had researched to reform the pack, but had limited success.

I've gone a little different route and use 2450mAh NiMH batteries and two La Crosse BC-700 chargers. The chargers are the "smart" type and allow me to monitor the individual health of each cell. I typically get 25+ hours per charge (using headphones and not using any screen backlight). When the pack gets low, I run them through a (low current) discharge/recharge cycle which takes about 14 - 16 hours. So far, I'm very pleased with their performance (been using them for ~2 years). The jury is out regarding if the cost of the batteries and chargers will ever break even with just buying AA alkalines, but we'll see. I've always got the AA alkaline option available in any case.

Best of luck on your next hunt! ----V-tail

[mrdee3]

Hello all this is my first post, thought I could help out on this. I’m new to metal detecting but know a lot about rechargeable battery’s. First the charger that comes with the DFX is not a smart charger as posted before, witch also means it has no peak detection. That being said with a good smart charger you can charge the battery at 1 C or 1X its capacity safely, so if it is for instance a 850mah battery could be charged at 850mah and it would take 1 hour to charge it.

I normally charge my AA’s at 2C and use a temp sensing peak detecting charger I normally get a minimum of a 1000 cycles out of good AA’s

The problem with wall wart chargers is that they slowly cook the battery. For instance if you only need 85mah to top off your battery and you let it plugged in over night say 8 hours (on over night charge mode) you just put 680mah into the battery, not good.

One side note to bring a rechargeable battery back if it is not to far gone you discharge it double at what it is charged, then recharge.

Rechargeable AA’s handled and charged properly will well out last alkaline they have a much higher discharge rate and are more stable less voltage drops. But remember NIMH or (nickel metal hydride) do have a higher self discharge rate meaning they discharge themselves sitting around. There are new batteries out that fix this problem as well, a good one in my opinion is Sanyo eneloop I use them and love them.