I guess I just don't understand

[sws33]

Why it is my CZ 21, with brand new fully charged rechargeable batteries, won't pick up a 15 gram gold wedding band past about 6 inches, but depleted alkaline 9 volt batteries will pick it up at 10 inches. I've tried high discharge rechargeable batteries, low discharge rechargeable batteries and neither, for whatever reason, seem to operate the CZ 21 as stable or as deeply as alkaline batteries. Is it just me? Or have other folks come across the same type of operation on rechargeable batteries? And if so, did you figure out why? I was hoping to save some money by not having to constantly buy batteries, but I don't want to use rechargeable batteries at the expense of stability and depth.

 

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[Irishgoldhound]

I’m sure Casper would know best about your CZ. I only use regular batteries. I put in new ones every hunt. Never liked using rechargeable batteries. In my experience they’re not quite as good as regular batteries with certain electronics. I buy batteries with my clad so it’s not that big of a deal to buy new, good batteries every hunt.

 

[Bill G]

Maybe someone with an electronics background can chime in on this one with an answer. I don't have a clue on what's going on with your CZ-21 concerning what you described.

With that said I gave up on rechargeable battery for my detectors a long time ago. I personally think quality alkalines are hard to beat. I have been buying the bulk pack Kirkland brand alkaline batteries from Costco. I find them every bit as good as Duracell alkaline batteries at a much better cost. I can't recall if I saw the Kirkland brand in 9v last time I was at Costco.

I do honestly feel that all my detectors have performed over all better with quality alkaline batteries in them. The issue as we all know is the hit to the old pocket book.

All The Best,
Bill G

 

[sws33]

I appreciate the replies, thank you. And also a big thank you to the Home Depot where I went to buy some fresh 9 volt alkaline. Lowe's had a sale on rayovac high-energy 9 volt batteries in a 12 pack for $13. I headed over to the Depot, they're much closer, and asked if they still do the "meet or beat" price thing. The cashier said, "I don't think so", and as she saw me starting to put them back said, "but I'll give them to you for 10 bucks a box". Yes please, I'll take two.

 

[stevemc]

I do know some detectors need a certain voltage, and can work better with higher voltage. On the AA batteries a rechargeable is 1.2 volts, where a throw away is 1.5- 1.6 volts. That is why on the ones that use AA, they put 2 more in the soldered together pack. For 12 volt anyway.

 

[madmantrapper]

I find the ROV batteries to be a piece of crap. I hope you have better luck with them then I have.

 

[smokeythecat]

I've had numerous brands of machines that took rechargeable batteries and regular alkaline batteries. I always found more and got more digging time with the regular alkaline batteries.

 

[ARC]

I appreciate the replies, thank you. And also a big thank you to the Home Depot where I went to buy some fresh 9 volt alkaline. Lowe's had a sale on rayovac high-energy 9 volt batteries in a 12 pack for $13. I headed over to the Depot, they're much closer, and asked if they still do the "meet or beat" price thing. The cashier said, "I don't think so", and as she saw me starting to put them back said, "but I'll give them to you for 10 bucks a box". Yes please, I'll take two.

lol... I notice you also got a "jumbo bouquet" per your receipt...

is that for the wife / girlfriend just prior to telling her you want to go metal detecting ?

 

[ARC]

The old recharges seem better... mine are like sheesh old.

Course I don't use them on any detectors... but my 580 uses 9v recharge and lasts eons.

They are the older energizers... which I prefer to Duracells.

My girls detectors both use AA's... also older energizer rechargers ... I am talking at least 10 years oldish.

own prolly 30 AA's 20 AAA's... and 2 9v;s... all have been used to hell.

2 reg chargers and 2 speed chargers.

Notice no differences.

My regular battery collection would boggle most. heh

 

[Rookster]

I've had better luck with the Copper Tops than any other.

 

[OBN]

I find the ROV batteries to be a piece of crap. I hope you have better luck with them then I have.

Amen to that!... Copper top batteries (Duracell Alkaline 9 Volt Coppertop Batteries) or the Energizer Advanced Lithium 9V Batteries Which cost way to much, but are the best is very cold conditions.

 

[Octopulse]

Are your rechargeable batteries rated at 9.6v......I used these some years ago and found them equal to the alkalines. Unfortunately, I got careless with the O-ring seal and salt water got in and destroyed the rechargeables. There's a lot to like with 40 hours run time on alkalines.
Tony

 

[Mudflap]

You may have one or more of those rechargeable 9 volt batteries with a shorted cell. Shorted cells drop the overall voltage of the pack. You might think it is charged however the terminal voltage on the battery is lower which causes issues with the detector. You can measure the terminal voltage with a DC voltmeter, the battery box full and the detector on. I use rechargeable batteries in a lot of things but never liked 9V rechargeable ones in my CZ. Use 9V alkaline in my CZ-21.

 

[Irishgoldhound]

Duracell or Energizer only! I won’t put anything else in a $1000.00+machine.

 

[DJWEHAGE]

CZ 20/21 for years and years. 9V Alks all the way. Duracell or Energizer. Usually change out after 20 hours, 4-5 hunts, or monthly -whichever comes first. Never had an issue with performance. Ever...

 

[sws33]

Thanks for all the feedback, I'll be sticking with the alkaline. I always check every battery with my volt meter before I put it in my toys, so no dead cells.

 

[dewcon4414]

YOu can check a battery ...... but until its put under load you know really know the true voltage. Its as important to find those with MAH too..... like Lith. Rechargables drop off faster than copper tops too... thus the MAH. Good example....... old Xcal 700 mah over time maybe 4 hours hunting.....lith 3000.... almost a week of good hunting same voltage as that 700 got ya.

 

[flgliderpilot]

Why it is my CZ 21, with brand new fully charged rechargeable batteries, won't pick up a 15 gram gold wedding band past about 6 inches, but depleted alkaline 9 volt batteries will pick it up at 10 inches. I've tried high discharge rechargeable batteries, low discharge rechargeable batteries and neither, for whatever reason, seem to operate the CZ 21 as stable or as deeply as alkaline batteries. Is it just me? Or have other folks come across the same type of operation on rechargeable batteries? And if so, did you figure out why? I was hoping to save some money by not having to constantly buy batteries, but I don't want to use rechargeable batteries at the expense of stability and depth.

The voltage of your batteries is sagging trying to supply the current .. you need better batteries. You'll see similar problems with cheap Harbor Freight batteries. I always use Duracell or Energizer for this reason.

 

[stevemc]

Dew, remember last week and my battery on my 25 plus year old Excal went bad? You recommended a brand, and it is coming. Before I ordered I charged it overnight and took it outside and it didn’t do anything. I checked voltage and it was 13.75. Still nothing. I plugged it into my wife’s Excal battery and fine. I plugged her control box in my battery nothing. I plugged in my control box cable and put the probes on it 13.75, then turned it on 1.65. Just like you said under a load voltage, is the only way to truly know. Just like a battery in a car or boat, it must be load tested to really know.

 

[bklein]

One cell bad in a 9V can result in a no load voltage reading in the “good” range.
Rechargeables may have higher internal resistance that does the same for ALL cells. What is the normal mA load on the battery? I’m not familiar with the detector but ideally for long duration hunts you’d want a lipo or li-ion pack with a regulator to give you the 9V or whatever - like what is done for my Minelab GP-Extreme. Is there any extra room in the battery compartment?