Do you use rechargable batteries?

[+Pat in Louisiana]

If so what do you find is the best?

Do you use different types for cameras vs. GPS?

[+The Find Its]

We use NiMH and they seem to work very well.

We do usually have a couple of Duracells in the back pack as they have a long storage life, just in case.

Nothing worse than being close to a smiley when the batteries die out.

[+StarBrand]

I use the Rayovac Hybrid rechargeables for about 1.5 years now - I love them!!

[+Knight2000]

I use the Rayovac Hybrid rechargeables for about 1.5 years now - I love them!!

What Star said. Pretty inexpensive and they work well.

[+Wild Thing 73]

Did the rechargeable, have all the "stuff", but not worth the effort....Alkaline is the best...long life and dependable....I have them every where...cache jacket, car, coat, pockets, re frig, freezer etc. They are always within reach. Also, they are much more cost effective. Happy Trails

[jholly]

Also, they are much more cost effective.

 

I would like to see the cost analysis to prove this allegation. Seems to me that $18 for four batteries and charger would be a LOT cheaper than say 300-400 batteries at $170-$220. But then maybe my calculator needs a new battery.

 

Jim

[jholly]

I use rechargeable batteries in the 76CSx and my palm. I use duracell and engergizer. Both last for the entire day of caching and charge quickly at night for the next time. When you use them in your GPS just be sure to switch the battery type from alkaline to NiMH.

 

Jim

[+Pat in Louisiana]

Can you mix N match or do you have to stay with brand/charger combinations?

[jholly]

Can you mix N match or do you have to stay with brand/charger combinations?

 

Shouldn't be a problem as long as the batteries are NiMH and the chargers are for NiMH batteries.

 

Jim

[+Airmapper]

I use the Rayovac Hybrid rechargeables for about 1.5 years now - I love them!!

What Star said. Pretty inexpensive and they work well.

Same here, they work great.

[sdarken]

After geocaching for a while I started to feel very guilty about the number of batteries I was using so I switched to rechargables. (I also use the Rayovac Hybrid). I've read that Sanyo Eneloops are very similar. These are a new generation of rechargables that hold their charge much longer that previous types.

[JohnMac56]

I use rechargeable batteries in the 76CSx and my palm. I use duracell and engergizer. Both last for the entire day of caching and charge quickly at night for the next time. When you use them in your GPS just be sure to switch the battery type from alkaline to NiMH.

 

Jim

 

Thanks for the advice Jim, I just started using rechargeables and didn't even remember that there was a battery setting in my 60CSx. Funny thing is that once I changed it from alkaline to NiMH my remaining battery charge indicator jumped from about 3/4 to full!!!

Edited September 20, 2008 by JohnMac56

[+Damin69]

I use rechargeable batteries in the 76CSx and my palm. I use duracell and engergizer. Both last for the entire day of caching and charge quickly at night for the next time. When you use them in your GPS just be sure to switch the battery type from alkaline to NiMH.

 

Jim

 

Thanks for the advice Jim, I just started using rechargeables and didn't even remember that there was a battery setting in my 60CSx. Funny thing is that once I changed it from alkaline to NiMH my remaining battery charge indicator jumped from about 3/4 to full!!!

That is Because Alkaline batteries are 1.5 volt so it is monitoring the voltage as such when you switch to NIMH it knows that rechargeables are 1.2 volts per cell so it monitors the batteries based on that voltage.

[+Night Stalker]

I use NIMH batteries and a MAHA charger. I end up replacing the batteries about every year and a half. I would hate to think how many non rechargeable batteries I would have gone through in the last 6 years if I was using them instead.

[+DonB]

I wouldn't use anything but the hybrids. I have Sanyo, Rayovac, and Kodak, they are all good.

[+xplorer7]

My experience, interspersed with the guidelines I have to offer, are as follows:

 

I use NiMH batteries with a MAHA MH-C401FS, and I've had a really outstanding experience with my strategy. I actually researched my choice of chargers pretty carefully, some are better than others.

 

Always elect a slow charge over a fast charge if your charger supports that choice and have the time: a slow charge is more gentle on the batteries and results in longer battery life: the higher heat generated during a faster charge is not your friend!

 

I pick a decent battery, there are a number of them out there to choose from. I try to get as high a Milliamp Hour (mAh) rating as possible, as batteries with a higher value last longer between charges. I'm currently using a battery put out by Duracell with a 2650 mAh rating which I've been very happy with. I've noticed that Powerex puts out a battery now with a 2700 mAh rating which I'd also like to try.

 

There are also low self discharge NiMH batteries available, which I haven't tried. They have the benefit of a much longer shelf life on a charge. A disadvantage of traditional NiMH batteries is that they do lose their charge after a few days. It's not an issue for me (at least for my GPS, other devices might be a different story), since I use my GPS most days. The trade-off is, that the low self discharge batteries I've seen in the stores seemed to tend to have a lower mAh rating than their traditional counterparts at the same price, offering a little less bang for the buck in exchange for the advantages they offer. Common sense would dictate that if you use your GPS most days the traditional NiMH batteries would be a good choice, but if you frequently go a week or two between geocaching or using your GPS the low discharge NiMH would work out better.

 

As for the Rayovac, Sanyo, etc., hybrid rechargables, I have not used them and I don't know a lot about them, but it sounds like they've also worked quite well for people based on what I see in this thread.

 

One thing I do recommend, though, is to not mix batteries of different types, ratings, or levels of charge at the same time. I start with pairs of new batteries from my GPS and always keep them paired up so that they're also the same age with the same number of charges. If one battery is discharged and the other one is charged, it's not good for the charged battery. If, on the other hand, the mix-n-match question referred to which brand of charger you can charge a given brand of battery in, for NiMH batteries, you need only use a charger designed to charge NiMHs. You do not need to use a Duracell charger for Duracell batteries, for example. Again, I do not know as much about the hybrid rechargables, so I'd confirm that the same is true for them from a reliable source (if I had to guess, I'd think it was fine as long as the charger was designed for hybrids, but don't take my word on that one).

[+DonB]

My experience, interspersed with the guidelines I have to offer, are as follows:

 

I use NiMH batteries with a MAHA MH-C401FS, and I've had a really outstanding experience with my strategy. I actually researched my choice of chargers pretty carefully, some are better than others.

 

Always elect a slow charge over a fast charge if your charger supports that choice and have the time: a slow charge is more gentle on the batteries and results in longer battery life: the higher heat generated during a faster charge is not your friend!

 

I pick a decent battery, there are a number of them out there to choose from. I try to get as high a Milliamp Hour (mAh) rating as possible, as batteries with a higher value last longer between charges. I'm currently using a battery put out by Duracell with a 2650 mAh rating which I've been very happy with. I've noticed that Powerex puts out a battery now with a 2700 mAh rating which I'd also like to try.

 

There are also low self discharge NiMH batteries available, which I haven't tried. They have the benefit of a much longer shelf life on a charge. A disadvantage of traditional NiMH batteries is that they do lose their charge after a few days. It's not an issue for me (at least for my GPS, other devices might be a different story), since I use my GPS most days. The trade-off is, that the low self discharge batteries I've seen in the stores seemed to tend to have a lower mAh rating than their traditional counterparts at the same price, offering a little less bang for the buck in exchange for the advantages they offer. Common sense would dictate that if you use your GPS most days the traditional NiMH batteries would be a good choice, but if you frequently go a week or two between geocaching or using your GPS the low discharge NiMH would work out better.

 

As for the Rayovac, Sanyo, etc., hybrid rechargables, I have not used them and I don't know a lot about them, but it sounds like they've also worked quite well for people based on what I see in this thread.

 

One thing I do recommend, though, is to not mix batteries of different types, ratings, or levels of charge at the same time. I start with pairs of new batteries from my GPS and always keep them paired up so that they're also the same age with the same number of charges. If one battery is discharged and the other one is charged, it's not good for the charged battery. If, on the other hand, the mix-n-match question referred to which brand of charger you can charge a given brand of battery in, for NiMH batteries, you need only use a charger designed to charge NiMHs. You do not need to use a Duracell charger for Duracell batteries, for example. Again, I do not know as much about the hybrid rechargables, so I'd confirm that the same is true for them from a reliable source (if I had to guess, I'd think it was fine as long as the charger was designed for hybrids, but don't take my word on that one).

I use the same charger as you do, among others. Also the hybrids charge the same as the regular NiMH batteries. I may be wrong where I read it, but it seems like someone in these forums did some testing on the hybrids and concluded that they gave better service then some of the higher mAh rated regular NiMHs did.

[+webscouter.]

The charger is the most important part of the equation IMHO. I use the MAHA charger like the others set for a slow charge.

 

I use a mix of the NiMH and Hybrid batteries for my trips. I am on the road for nine days and have the batteries in my gps and eight more pairs. I use the NiMH first and the hybrids latter in the week. I keep them in a battery case with the charged batteries positive pointing right and the used batteries pointing left. I keep them in matched pairs and have them marked as to when I purchased them. I have a pair that it just past 5 years that will need to be replaced soon as it is only giving me about 8 hours of use compared to 13 for the others. My GPS is on for most of the day while on the road and so far I have never run out of batteries with this setup. I also use the conditioning setting about every other month on the batteries.

[+BCandMsKitty]

I have a magellan which uses a proprietary Li-Ion battery, (extra and expensive, IMO). It comes with a carier that clips in to handle 3 AAA batteries. I use this setup for a while with rechargeables and had to change the batteries about 3/4 through a day of caching. Then I found a cell phone battery (Motorola T720/T730) for a fraction of the expense of the magellan battery. I can get over 2 days of caching now before the battery dies. It charges in the GPSr in 5 to 6 hours via USB. I keep the AAA batties charged and ready to go for emergency backup.

[+Pat in Louisiana]

What about the AC charger.

Anyone tried using one with a DC/AC inverter in your car?

[+michigansnorkelers]

What about the AC charger.

Anyone tried using one with a DC/AC inverter in your car?

 

My Energizer charger has a car adapter. On long trips, I always have 4 batteries in the charger, two in the GPSr and a spare set in my cache bag.

 

Another handy item, which I might buy someday, is the car adapter for the GPSr unit. They're pricey at $21 though.

[+webscouter.]

The MAHA chargers come with both house and auto adapters.

[+Kohavis]

Be careful when buying a charger for NiCd or NiMH - "fast" chargers can kill the batteries quickly. A tell-tale sign is heat - if the battery gets warm when charging, drop-kick that charger into the nearest dumpster.

 

Use a CONSTANT CURRENT charger for these types of batteries. This is in contrast to lead acid and lithium ion batteries which seem to like CONSTANT VOLTAGE chargers better.

 

Another thing to remember is that NiCd and NiMH batteries love to be deep cycled, and both have memory for how far they were discharged last time, although NiCd is worse in this regard.

 

Lead acid and Lithium Ion batteries, on the other hand, prefer to be constantly topped off, and don't last as long when discharged all the way repeatedly. That's why your cell phone battery loves to be charged every night even if you only used it a few minutes

 

Rule of thumb for NiCd and NiMH - Charge at 1/10 the rated capacity for 14 hours. If it's a 500 MaH battery, charge at 50 mA for 14 hours and your batteries will last the longest.

 

The reason it's 14 hours and not 10 for the charging time is because of inefficiency (losses). The battery doesn't convert the charging energy perfectly to chemical energy.

[+Team Birdaholic]

I use common old energizer rechargables. Nimh. I always run them right down till I cant turn the gps on and then in a slow charger takes about 6 hours to charge. These will give me a good 28 hours on the gps but I never use the backlight, and the compass is always on. The main point is - make sure they are flat before charging and then charge in a slow charger. using a 76CSx.

Edited September 22, 2008 by Birdaholic

[+johnling]

Duracell. They are 2650mAH. They last a long time between charges. The longest total time I know I have used them was 35 hours and they had several cache trips on them prior to that. I only carry one set of spares just in case.

[+fizzymagic]

I don't use rechargables. I tried and it didn't work for me. For the following reasons:

• NIMH batteries lose charge slowly after being recharged. It's hard to keep track of how long ago you charged each set.
  
• NIMH batteries die quickly once the voltage starts to drop; battery life indicators don't work.
  
• NIMH batteries last considerably less time in my GPS than alkalines, even fully charged.
  

[+Pat in Louisiana]

Should I place my semi drained batteries in a flashlight or something and completely empty them prior to re chargeing?

How important is it to not charge them if they arn't dead?

Edited September 22, 2008 by Pat in Louisiana

[+SWiggles]

I've been using Sanyo Eneloop batteries for about a year now. They don't loose their charge like NiMH. They provide much longer life per charge than the alkalines I was using.

[+Damin69]

Be careful when buying a charger for NiCd or NiMH - "fast" chargers can kill the batteries quickly. A tell-tale sign is heat - if the battery gets warm when charging, drop-kick that charger into the nearest dumpster.

 

Use a CONSTANT CURRENT charger for these types of batteries. This is in contrast to lead acid and lithium ion batteries which seem to like CONSTANT VOLTAGE chargers better.

 

Another thing to remember is that NiCd and NiMH batteries love to be deep cycled, and both have memory for how far they were discharged last time, although NiCd is worse in this regard.

 

Lead acid and Lithium Ion batteries, on the other hand, prefer to be constantly topped off, and don't last as long when discharged all the way repeatedly. That's why your cell phone battery loves to be charged every night even if you only used it a few minutes

 

Rule of thumb for NiCd and NiMH - Charge at 1/10 the rated capacity for 14 hours. If it's a 500 MaH battery, charge at 50 mA for 14 hours and your batteries will last the longest.

 

The reason it's 14 hours and not 10 for the charging time is because of inefficiency (losses). The battery doesn't convert the charging energy perfectly to chemical energy.

I have been an RC Car racer for many years. I have raced both Electric class and Nitro. As far as rechargable batteries go. Here is a segment from another site.

It's best to recharge batteries slowly.

 

(Not true. See next item).

 

Quick charging NiMH batteries will reduce their life.

 

For practical purposes with batteries that are designed to be quick charged, for example, Sanyo, GP, POWERhaus, that is not true. It is important to use a battery charger that has been specifically designed to rapid charge NiMH cells. Actually there is a much greater likely hood of reducing the life of a NiMH battery by using an "overnight" charger than by using a smart fast charger. Overnight chargers rely on the fact that you will unplug them after a number of hours. If you forget to unplug them they can continue to charge the batteries longer than they should. Overcharging WILL reduce the life of batteries. From a strictly technical sense, a battery that is always slow charged will likely last a little longer than one that is always rapid charged. However, the difference is so small that it is not likely to be noticeable for most users.

 

Here is bit more information from http://forums.batteryspace.com/forums/viewforum.php?f=9

 

Most battery questions can be answered on this FAQ page.

 

 

Will Quick charging NiMH batteries reduce their life?

--------------------------------------------------------------------------------

 

Actually, all NiMH batteries required 3-4 times deep and slow charging processing before reaching its peak capacity.

 

If you like quick charger, it is important to use a charger that has been specifically designed . Some low quality quick charger will slightly decrease the battery life. However, there is a greater likelyhood of reducing the life of a NiMH battery by using an "overnight" charger than by using a smart fast charger. Overnight chargers rely on the fact that you will unplug them after a number of hours, unless it is time controllered. If you forget to unplug them they can continue to charge the batteries longer than they should. Overcharging Will reduce the life of batteries. [From a strictly technical sense, a battery that is always slow charged will likely last a little longer than one that is always rapid charged] However, the difference is not big for most users.

 

=======

 

NIMH do not have memory like NICads have. They do not require that you completely discharged before charging. In RC general rule of thumb and as most battery manufactures will say charge safe at for AA batteries never charge above 1.5 amps. On my transmitter packs I charge them at between 500-700 mah. that is on a specialized peak charger. On my GPS AAs I have a standard AA charger that is 900 mah.

My AA are all around 2 years old and still going strong.

[+SniperChicken]

After going through a ton of alkalines (we go on a lot of all day cache trips) i decided to switch to rechargeable nimh batteries for the gps unit,flashlights..etc. It has saved us a LOT of money in the long run.We have a 12 volt DC quick charger that keeps a spare set of AAs in full charge as we geocache.We also keep several pairs of rechargeables on hand. The main drawback to using any non lithium rechargeable battery is that they lose their charge over time.Some lose the charge even quicker than others. We just pop in an automatic charger,when it says they are fully we put them into the device and start charging a back up set of batteries. They do tend to lose their voltage drastically towards the end of the charge. As far as draining them completely before charging them ...my thoughts are that it isn't worth the extra effort to gain an extra few minutes of use. I'll just pop in my extra set of batteries and get back to geocaching!

[+xshooter]

I've been using these Tenergy batteries as dicussed in this thread http://forums.iowageocachers.org/viewtopic.php?t=1786

So far I've been real happy with them. It seems that my CO runs better on the NiMH batteries than on alkalines.

[+Jester966]

Has anyone used, or know anything about, the newer rechargeable Alkalines from Pure Energy? I just bought some today. From what I have read so far, the newest "generation" of rechargeable alkalines are far superior to the previous (failed) RAM products. In theory they sound like they've got the best of everything, but I suppose I will have to wait and see how they perform in the real world...

[+Snake & Rooster]

I'm using Duracell 2650mAh NiMH batteries for a long time now. I've read the literature that says to charge them slow. I've read the literature that says to charge them fast. I choose to do it fast. Have I decreased the overall life of the batteries by doing so? Maybe, but I'm guessing that it isn't by much. They've all been recharged at least 100 times and are still going strong. I am using them in an Oregon 300 with the backlight on 100% at all times. I can get 10-12 hours of caching and still have juice left.

 

The current generation of NiMH batteries don't have the memory problems of NiCad or earlier NiMH batteries. You do not need to drain the down before recharging them. Yes . . . I know that you will find literature both supporting and countering this claim too. I will just say that I have not experienced any decrease in performance over time.

 

Do these batteries loose a charge over time when not used? Yes. But it is temperature dependent. I leave my spares in the refrigerator. If I leave them in there for a month, I suppose I might see a 4 or 5% drop. Since I actually cache every week, they seldom sit in there that long.

 

Finally, in newer GPS receivers that have a NiMH battery setting, the meter isn't bad at showing you what is left. Your experience may vary, yada yada yada.

Edited September 22, 2008 by Snake & Rooster

[+Kohavis]

For practical purposes with batteries that are designed to be quick charged, for example, Sanyo, GP, POWERhaus, that is not true.

Why? Because the guy who sold you the batteries says so? they have to justify charging more

 

They may have designed in some longer life aspect that will extend the battery's life somewhat when rapid charged, like using purer cathode materials. But the same given battery will always last longer when slow charged. Whether or not its life when fast-charged is adequate for you or not is a judgment call.

 

It's a simple law of electronics called Ohm's Law. Power dissipated = Current squared times resistance. It's inescapable. A battery has inherent resistance (called impedance for AC). Increase the current flowing through it (required when fast-charging it, whether pulsing or steady state - the duty cycle is still increased) and you increase the heat generated internally. Any materials scientist can tell you that heat shortens the life of everything. No exceptions. Coffeemakers, car CD players, cameras, Intel Core 2 CPUs, Hershey bars ....and batteries.

 

Take one of those so-called "fast charge" batteries and do your own test if you don't believe me. Discharge two batteries at the same rate. Charge one at a fast rate and one at a slower rate. Then tell me which one dies first

[+Damin69]

For practical purposes with batteries that are designed to be quick charged, for example, Sanyo, GP, POWERhaus, that is not true.

Why? Because the guy who sold you the batteries says so? they have to justify charging more

 

They may have designed in some longer life aspect that will extend the battery's life somewhat when rapid charged, like using purer cathode materials. But the same given battery will always last longer when slow charged. Whether or not its life when fast-charged is adequate for you or not is a judgment call.

 

It's a simple law of electronics called Ohm's Law. Power dissipated = Current squared times resistance. It's inescapable. A battery has inherent resistance (called impedance for AC). Increase the current flowing through it (required when fast-charging it, whether pulsing or steady state - the duty cycle is still increased) and you increase the heat generated internally. Any materials scientist can tell you that heat shortens the life of everything. No exceptions. Coffeemakers, car CD players, cameras, Intel Core 2 CPUs, Hershey bars ....and batteries.

 

Take one of those so-called "fast charge" batteries and do your own test if you don't believe me. Discharge two batteries at the same rate. Charge one at a fast rate and one at a slower rate. Then tell me which one dies first

That was not my Quote but off of a Battery site. And that was referring to SUB C batteries. Fast rate for RC racing also means FASTER rate Discharge(20-30AMP draw) also.

[+Kohavis]

I'm not disputing that they can handle fast charge and discharge rates. I'm just saying that the batteries will last longer if you charge them slower, and discharge them slower. Any time you generate heat, you shorten its life. It may still have an acceptable life with those demanding conditions, but all other things being equal, the one charged and discharged slower will last longer. That's all I'm saying

 

 

Edit to clean up typos. I'm typing with gloves on tonight

Edited September 22, 2008 by Kohavis

[+Guinness70]

GP Power 2700 NiMH rechargeables

2 of em last about 6-8hours on a Garmin Colorado 300

 

takes a while to rechargen so leave them in the charger overnight.

got 4 sets of 2

always 1 set in the GPSr and at least 2 sets back up and often 1 set in the charger.

have a GP Power recharger which can also be used in the car. havent used it but could be handy.

 

would be very costly not to use rechargeables

Edited September 22, 2008 by Guinness70

[+Kohavis]

Unless my Venture HC suddenly turns into a power hog, I probably won't need rechargeables. I just replaced the batteries after about 50 hours of "on time". That's two AA alkaline, which aren't going to break the bank if I have to replace one set every two weeks

 

Edit: I forgot to mention - there's a "reconditioning" procedure I used to perform on old NiCd batteries that I only recommend you do AT YOUR OWN RISK!!!! I've never tried it on NiMH, but since the chemistries and characteristics of both battery types are similar, it would probably work.

 

If your battery seems to be suffering from pronounced "memory effect", that is, it doesn't work very long before needing recharging, you can try this last-ditch step before you toss it. I recommend you use safety goggles for this:

 

Use your car battery charger to "nuke" the battery. Over time, oxides and other molecules form on the cathode and affect performance. A build-up of this can cause severe memory effect. What you do is plug in your car charger (a high-current power supply), briefly touch "+" to the "+" terminal on the battery, and "-" to the "-" terminal. By briefly I mean 1 or 1-1/2 seconds. Never more than two or the battery could explode.

 

You'll see the ammeter in the car charger jump up to something like 6 or 8 amps.

 

Then let it cool for a few hours and charge as normal.

 

This is a drastic step, and nobody who sells the batteries would recommend it, for liability reasons, of course. But if you've already written off the battery, it won't hurt anything to try it, and it might give you many more charge/discharge cycles before the battery finally gives up the ghost. Just remember: NEVER MORE THAN TWO SECONDS!

 

My disclaimer: I assume no liability in the above advice. You do it at your own risk, and I cannot be held accountable for any injury or damage to property as a result.

Edited September 22, 2008 by Kohavis

[+Guinness70]

Unless my Venture HC suddenly turns into a power hog, I probably won't need rechargeables. I just replaced the batteries after about 50 hours of "on time". -//-

50hours on a Venture HC? flippin heck ! i get 6-8hours from the colorado ... dang

[+Prime Suspect]

Unless my Venture HC suddenly turns into a power hog, I probably won't need rechargeables. I just replaced the batteries after about 50 hours of "on time". That's two AA alkaline, which aren't going to break the bank if I have to replace one set every two weeks

The Venture HC is rated at a 14 hour battery life. There's no way you're getting 50 hours out of normal alkaline batteries.

[+Kohavis]

Unless my Venture HC suddenly turns into a power hog, I probably won't need rechargeables. I just replaced the batteries after about 50 hours of "on time". That's two AA alkaline, which aren't going to break the bank if I have to replace one set every two weeks

The Venture HC is rated at a 14 hour battery life. There's no way you're getting 50 hours out of normal alkaline batteries.

This past 2 weeks I just did. I don't care what it's rated at.

 

It was a pair of fresh Duracell Alkaline. I don't use the backlight except when it's connected via USB.

[+StarBrand]

I don't use rechargables. I tried and it didn't work for me. For the following reasons:

• NIMH batteries lose charge slowly after being recharged. It's hard to keep track of how long ago you charged each set.
  
• NIMH batteries die quickly once the voltage starts to drop; battery life indicators don't work.
  
• NIMH batteries last considerably less time in my GPS than alkalines, even fully charged.
  

Have you looked into the Hybrid NimH? They lose charge far more slowly than ordinary ones and don't die off as quickly on the backend while you meter still show power.

[+Prime Suspect]

Unless my Venture HC suddenly turns into a power hog, I probably won't need rechargeables. I just replaced the batteries after about 50 hours of "on time". That's two AA alkaline, which aren't going to break the bank if I have to replace one set every two weeks

The Venture HC is rated at a 14 hour battery life. There's no way you're getting 50 hours out of normal alkaline batteries.

This past 2 weeks I just did. I don't care what it's rated at.

 

It was a pair of fresh Duracell Alkaline. I don't use the backlight except when it's connected via USB.

If you're hooking it up to USB while driving around, it's not drawing power from the batteries during that time. It's using the 5 volts supplied by the USB connection.

[+Kohavis]

I don't use it in the car. The USB connection is used to transfer tracks and waypoints back and forth to my PC, maybe 5 minutes a day.

 

I think we've threadjacked this topic sufficiently. Let's drop it

[7rxc]

Should I place my semi drained batteries in a flashlight or something and completely empty them prior to re chargeing?

How important is it to not charge them if they arn't dead?

 

I've been catching up on reading this thread... I haven't seen what kind of batteries you are using...

 

The Rule is that most rechargeables NiCd or NiMh should not discharge below 1 volt per cell when used as a battery... that is 6 cells nominally 7.2 volt battery should never go below 6 volts. Most devices have this built in as a cutoff ( actually cells x 1v for what ever you use ) I have a 45xl (an older unit) and it cuts off at 4 volts, 4aa x 1v). This prevents problems with mismatched cells. At lower voltages the weakest cell drops a bit faster, and can get into a situation where it actually reverse charges from the other cells... that is it ends up effectively in backwards... and then it will drag down the voltage when you try to charge it... not good... As for Using cells for other things after they come out of your GPS etc. I often use them for flashlights and use them til they dim... not totally dead. I like the NiMh batteries myself, use the recondition mode every couple of months... One can talk about battery life, but I prefer to conserve juice... the GPS is turned off except when I'm navigating or marking a waypoint for my return trip... I don't like depending on

the auto track... just mark the car, major turns/hazards, and the target as waypoints... I get good use out of my 4aa's and always have spare alkalines in case. Mine has power saver mode as well.

Biggest thing is timing the cache trip... I always try to recharge the night before if possible for max effect.

I can't find time for more than a few hours of actual hunting... but frankly the laptop is a bigger battery life problem than the GPS.

 

Doug VE7RXC

[7rxc]

 

Edit: I forgot to mention - there's a "reconditioning" procedure I used to perform on old NiCd batteries that I only recommend you do AT YOUR OWN RISK!!!! I've never tried it on NiMH, but since the chemistries and characteristics of both battery types are similar, it would probably work.

 

My disclaimer: I assume no liability in the above advice. You do it at your own risk, and I cannot be held accountable for any injury or damage to property as a result.

 

I have used that technique for assembled batteries, and zapping for cells... Nicads that is...

There are some reasons why it doesn't work all the time of course as you probably know... usually baked off cells -no electrolite left... etc.

 

I have used a similar method to recover 'flat' Nimh cells individually... but only use an old GelCell cube charger for 6 v leadacid batteries... not much current... My subject cell usually has no voltage detectable, and resists any attempt at normal charging in a charger... especially with a good but discharged cell.

Same thing... plus to plus, minus to minus, but I make and break contact over several seconds, again to avoid heat build up. After that, the voltage is usually up above 1.2 v and I leave it for a while... that gives some of the buildup to clear... when I have two (why do chargers always need two at a time... I know of course, economics and practicality... 1.4 v regulators are rare, higher values are cheaper) anyway two cells,

I put them on the charger for a charge cycle... after a few days charged, a recondition cycle. Old Nimhs need that c-d-c-d now and then... for that matter so do Nicads... Voltage is only part of the problem, a thing called ampacity is what causes batteries to go dead quickly... that build up you mentioned reduces it. Higher voltages burn it away slowly... charging uses higher voltages (and sometimes currents)...

By the way the problem with fast charging cells is the way cells deal with gas generation... and recombination... excess gas is vented off, never to return... burnoff. High charge rate cells combine more and more quickly, not that much difference though... you are correct... low and slow is best ... unless.

You covered most of my points well... Doug VE7RXC

[+Kohavis]

Thanks for sharing that, Doug. Good stuff!

[+MarshMonsters]

We use energizer. We have a few chargers and one of them has a car adapter which is great to have on a cache run or while camping.

[richardhiggins]

I use rechargables for two reasons. First, they are much cheeper than non rechargable batteries. The second reason is for ecological reasons. Geocashing has taken me to some of the most beautiful places in the world. I don't want to add chemically or trash to the extent I can. Recharging good rechargable batteries is a small cost for the monitary and substance waste I save.

[+trainlove]

Does anyone know of a charger that will allow you to charge individual NiMh batteries? Not pairs of them!

I have some batteries that I suspect are not 100% good anymore and don't want to mix-n-match good and bad.