Rechargeable vs Alkaline

[U.K. Howard]

Would anyone care to offer an opinion as to whether the majority of detectors (more specifically Safari, Etrac, DFX etc.) will operate equally as well using standard rechargeables (AA 2400 to 2900mah Duracell etc), as they will using Alkalines (non-rechargeables)? I realise that the non-rechargeables are 1.5 volt and rechargeables are 1.2 volt, so will this reduction in voltage make a significant difference to the depth capabilities of a given machine, or is it more the case that a machine will either work, or won't work, and that some variation in voltage makes no difference? Also, how do manufacturers own rechargeable packs compare with standard rechargeables? Let's suppose machine'A' requires 12 volts to operate. Would one be right assume that the manufacturers own rechargeable battery pack which is physically the same in size as 8 x AA cells, rated at 1.5 volts each, is capable of providing the exact 12 volt requirement of the machine, as opposed to, let's say, 8 x 1.2 volt rechargeables, totalling only 9.2 volts? What gives?

 

[sprchng]

I'm sure someone who actually knows will chime in but I stayed at a Holiday Inn last night and can pretend or at least tell you what my opinon is.
Most machines reduce the 12v down to a lower operating voltage(9.6 or 9.4) and the higher voltage of alkalines just translates into a greater run time versus better performance. I use both in both the 75ltd and e-trac and it appears the rechargeables don't last as long and you have a low battery indicated as soon as the voltage begins to drop below 9.4 or so. They also die faster when they get to that point. Testing shows the rechargeables max out near 1.37v but taper quickly to 1.28v when new. Their "shelf " life is also very bad compared to alkalines so I use them on a constant rotating basis and save the alkalines for those "emergencies" when I stay at a Red Top and forget to plug things in.

Haven't tried the lithiums yet ---too costly.
Best rechargeables I have used are the eneloops

 

[MarkCZ]

The lower voltages will not impair performance!
The electronics inside the detector uses a built in regulator, meaning that they actually run at a lower voltage then the total supplied voltage.

These are not real numbers but rather for example (but close)

A detector that runs on a 12v supply might be regulated down to 10 volts, or maybe even 9 volts, or maybe even 8 Volts.

One that runs on a 9 volt power supply will often times actually run at 5 volts.

Now, you may get less run time with rechargeables then with premium Alkalines. But your performance of operation would be the same.

TIP!
If you go with the rechargeables. get the "LSD" (Low Self Discharge) type, they can be stored for up to a year without being recharged!

Also, you can adjust your math just a bit, the rechargeables are 1.25 volts which the .05 volt isn't much, but it adds up in a group. 8X1.25= 10 Volts.

Another advantage that rechargeables has is they don't drop off slowly, they maintain their output for they life of the charge then drop off all at once. So, the Alkalines start out at 12 volts and are regulated down to somewhere around 8 to 9 Volts, as you use them they start to fall off slowly until they reach the "Dead Zone" of the regulated voltage. The rechargeables don't start out as high above the regulated voltage, but they are well above the "Dead Zone" and don't slowly drop.

Mark

 

[KinTN]

I'm no expert but will relate my own experiences....

I ran my Safari with coppertop alkalines when I first got it. They went bad after about 15 hrs. By that time, I had done some research and decided on Eneloops with a MAHA smart charger. I have run these ever since that first set of alkalines and get about 15 hours a charge on them. I've had the Safari for about 3 yrs iirc and the Eneloops are used for nothing except that machine. I cant tell any difference in Eneloops v alkalines as far as performance in my detector goes.

pls note that the Eneloop tech is different from all the other rechargeable types, or so Sony claims. When saying "rechargeables do xxxxx", it really should be specified what type of rechargeable you are talking about. (not a slam at anyone, just a pertinent observation as I didn't really read the above responses)

 

[sprchng]

eneloops run good , no doubt about it. I notice they last longer than the rechargeable pack supplied by Minelab but if they sit in the holder for a week before I use them I notice the charge indicator on the e-trac loses the top bar just like with other rechargeables. Not so with alkalines. Sony claims a 3 year shelf life---I'd like them to elaborate on that as I see no indication that would be possible , at least with my connotation of the term "shelf life" .

 

[CopyTech99]

You will likely loose a bar quick with rechargables..... but beats buying throw away cells.

Avoid the fast chargers, they will cook your batteries.

I use the lowest current setting on my La Crosse.

 

[KinTN]

Should add that I have 3 sets of Eneloops that I rotate thru my Safari, so any given set sits for weeks after charging before being used.

 

[U.K. Howard]

Thank you to all who have contributed answers to my original post, all of which are interesting, informative, and appreciated. I have been looking at getting some Duracell StayCharged AA Rechargeable Accu NiMh Batteries (2000mAh), or Extreme 2900 mAh AA NiMH Rechargeable Batteries. I am no expert, but I am guessing that the Duracell variety would be better, as they 'stay charged' - but then their current rating is lower at 2000mAh, as opposed to the stated 2900mAh of the Extreme cells. I am guessing that current rating is also important? As for standard alkaline cells, I have shortlisted the following 2 types - AA LR06 AM3 ENERGIZER INDUSTRIAL ALKALINE BATTERIES and AA DURACELL PROCELL ALKALINE BATTERY BATTERIES 1.5v LR6 MN1500. Can anyone confirm these as wise choices, or do you know of a better solution. As for chargers, I have a couple of older slow chargers, and a new fast charger with a digital display. From what you say, I would be best to avoid using the fast charger, which is also supposed to recharge standard (non-rechargeable) alkaline cells - but does anyone know if this is really possible, as the few I have tried seem to show as recharged on the digital display, but only seem to give poor results when re-inserted into such devices as digital camaras, etc. I always understood that non rechargeables should never be recharged, so is this idea not good? As for the Eneloops, I managed to find these on eBay.co.uk, and they appear to be made by Sanyo? They do appear more expensive than the Duracell variety. Are they worth the additional expense? Oh, and how about AA Nimh? I can only seem to find one or two AA Nimh which are being advertised by sellers in Hong Kong etc. Does anyone know when will we be able to buy AA Nimh batteries from reputable makers such as Duracell, and will these charge using standard chargers?

 

[KinTN]

Oops, Sanyo not Sony. Yes, Eneloops are the top of the line as are MAHA chargers imo. Agree with slow charge on whatever you choose. I buy mine from Thomas Distributing (I am only a satisfied customer).

I'm sure that all of the above choices will work well fwiw.

 

[MarkCZ]

Higher current should give more run time!
But, all the Highest current ones I've seen are not the "LSD" type.

The higher current (MAX current) that are not the Low Self Discharge type typically have a two week shelf life, these are also all the normal Nickel Metal rechargeablels.
So, that's means that after they are charged you can leave them laying around very long before you use them. (They have a rapid self discharge rate)

The "LSD" are much better than non LSD's in that they can be also used as backup batteries.
I would recommend a newer "Smart Charger" They do a pretty rapid charge but the LSD's and the smart chargers are matched up pretty good. I would also get a charger that has a "Refresh Cycle".

Yes, you can expect some battery meters that are calibrated for X number of Alkaline's to lose the top one or two bars pretty quick just because the start off voltage of the rechargeables is more towards the dead zone of Alkalines. And if you put them in HOT off the charger that will show a little bit higher charge then they would if you put them in after a day or so off the charger. But ALL batteries HOT off the charger do this and it takes a little while for them to settle down to their own real voltage, that doesn't mean that they are discharging rapidly, it just means that the charger voltage that warmed them up tends to raise the batteries voltage a little higher than the battery can actually hold, or maintain.

Mark

 

[edjcox]

My Safari is running on a rechargeable LI pack.... It keeps going and going...

Minelab now sells the CTX that way...

 

[Tom_in_CA]

N/T