Further Discussion Of Nimh

[+Wandering Bears]

I started a thread a week or so ago about the MAX batteries, and got an overwhelming response in favor of NiMH batteries. So I decided to take the plunge. While at Target last night I picked up a set of Energizer NiMH 2500 mAh. I was noticing last night that they are only 1.2V, whereas a conventional alkaline battery is 1.5V.

 

I assume our GPSrs are not voltage-sensitive? (Mine's a Magellan SporTrak Map)

 

I haven't had a chance to test drive these NiMH as yet, since I had a brand new set of AA alkalines in the GPSr, but I'm looking forward to trying them out, probably this weekend.

Edited January 31, 2006 by Wandering Bears

[ImpalaBob]

If you were measuring with a volt meter ..... I'd say that's about right for their first charge. They will improve after several cycles of discharging and recharging .... called conditioning .... and should settle out around 1.4 volts. This is another major difference found when purchasing a "premium" NiMH as they will carry a higher voltage with the same milliamphour rating.

 

This is why most GPSs have settings for battery type. The supplied voltage and drop off curves are different for alkylines and NiMH.

 

GPS units operate on a range of voltage .... usually with a special over voltage protection circuit to prevent damage. On my MAP60C I can initialize with diagnostic mode and actually see the current voltage level supplied by the batteries. ImpalaBob

[+Isonzo Karst]

I was caching with a friend who told me that she found a place in "Set-up" on her Garmin to indicate battery type, and that when she changed it to the correct type (she had also just started using rechargeables) it considerably extended battery life. I checked my MeriGold and found nothing in set-up for battery type. I wonder if a newer model might have it? I go back and forth between different battery types and have never noticed any problems.

[+welch]

I was caching with a friend who told me that she found a place in "Set-up" on her Garmin to indicate battery type, and that when she changed it to the correct type (she had also just started using rechargeables) it considerably extended battery life. I checked my MeriGold and found nothing in set-up for battery type. I wonder if a newer model might have it? I go back and forth between different battery types and have never noticed any problems.

Apperently all that telling the gps what battery its using allows for correcting the battery meter. If your using a different type, or can't change it, its not a problem its just the 'power' bar may not be accurate. If your changing them before they go totally dead, you may be changing batteries before you need to.

[+nfa]

I love the 15 minute charging Ray-O-Vac batteries for caching...I can throw them in to charge when I start thinking about heading out, and 2 sets of each size (AA & AAA) are ready before I am.

 

Does anybody else love them? Why or why not?

 

jamie

[+nfa]

edit for double post...forum acting oddly for me...anyone else?

Edited January 31, 2006 by NFA

[+Miragee]

I have the 15-minute Energizer batteries and really appreciate the 15-minute recharging.

 

I also have an inverter for my car, so I can take the charger along and get fresh batteries in only 15 minutes.

 

This is really nice if you are camping, and not driving long distances. Last spring when I was camping at Joshua Tree National Park, I thought I was going to have to go to town and get a motel for one night, just so I could recharge the proprietary battery for my camera and the laptop battery.

 

I wish I could recharge the batteries for those two things in only 15 minutes.

[+Airmapper]

Quick question, I recently got some 2500 mAh Energizer rechargeable. Do I need to completely drain them before recharging? I have two in the GPS (They won't die!!!! It just keeps going!!!) but the ones in my Digital camera finally went to low to power the unit, so I recharged them, were they really dead, or do I need to find a way to completely drain them.

[+media601]

Quick question, I recently got some 2500 mAh Energizer rechargeable. Do I need to completely drain them before recharging? I have two in the GPS (They won't die!!!! It just keeps going!!!) but the ones in my Digital camera finally went to low to power the unit, so I recharged them, were they really dead, or do I need to find a way to completely drain them.

This is from the Nimh FAQ on the Maha energy site:

 

"Generally speaking, NiMH batteries do not suffer from the "memory effect" and thus do not require conditioning. Nevertheless, to ensure top performance, conditioning is recommended once for every ten charges. For Nickel Cadmium (NiCD) batteries, conditioning is recommended every time you charge your batteries."

 

When they talk about "conditioning" they are referring to special conditioning circuitry built into their chargers. I'm not sure if all chargers have that, but completely draining the batteries before charging has the same effect. So they are saying you should completely drain them approximately once for each ten charges.

 

I'm not an expert, but my guess is that letting them go dead naturally is all you need to do--no further draining should be required.

[+budd-rdc]

Quick question, I recently got some 2500 mAh Energizer rechargeable. Do I need to completely drain them before recharging? I have two in the GPS (They won't die!!!! It just keeps going!!!) but the ones in my Digital camera finally went to low to power the unit, so I recharged them, were they really dead, or do I need to find a way to completely drain them.

Short answer: Nope! You don't need to worry about discharging your batteries.

 

In many cases, "memory effect" of rechargeables (especially the old NiCd's) were due to permanent damage from overcharging. In the past, people drained/discharged batteries so they could find a repeatable method of charging them to full capacity while minimizing the chances of overcharging.

 

Modern chargers are much smarter and know when to stop charging, so this should no longer be a problem.

[+JDandDD]

Actually, all equipment is voltage sensitive. As you drain the batteries you will notice that the voltage goes down. All equipment will stop working when a certain voltage level is reached. For instance, the original Palm III worked between 2volt and 3 volt. The batteries were dead at 2 volts and the equipment will stop.

 

NiMH will show a lower starting voltage but that just means that your GPSr won't show a full meter. However, the battery will last at least as long as alkaline in my experience. Note: I have used 1850mHa and 2100mHa but not the 2500mHa type.

 

JDandDD

[+Airmapper]

Thanks for the responses.

 

I'm very satisfied with the performance on these batteries so far, my GPS is pretty easy on batteries anyway, and with the rechargeables it keeps going and going. My Digital camera was almost useless without them.

[+Sonoran Privateers]

I haven't used the Nimh batteries in my GPS yet, but I sure will be soon! I bought some for my digital camera right before I went to the Bahamas. I was gone for 10 days, took over 150 pictures, 10 video clips, and spent oodles of time downloading pictures onto my laptop every night. I didn't charge the batteries once the entire trip. In fact, I came home and am still using it and havn't charged them.

 

I bought the Energizer 2500 mAh ones. I would recommend them to anyone.

[+CharlieP]

I was noticing last night that they are only 1.2V, whereas a conventional alkaline battery is 1.5V.

 

I assume our GPSrs are not voltage-sensitive? (Mine's a Magellan SporTrak Map)

Don't worry about the voltage difference. Most devices designed for alkaline batteries will operate in a range of about 0.9 to 1.5 volts. This is because alkaline batteries drop voltage as they discharge, and go dead at about 0.9 volts. If a device would not tolerate a voltage less than 1.5 volts, it would only use a small fraction of the capacity of an alkaline cell.

 

But it is good to be aware that the battery level indicator on your GPS may be misleading when you use NiMH batteries. It will probably indicate about 90% when the batteries are fully charged, drop to about 50% within an hour or so, and go dead (about 16 operating hours later) when the indicator shows about 30%. Its just the difference in the discharge curve of the NiMH. Some devices allow you to adjust the indicator to recognize the NiMH difference.

[+Mudfrog]

I love the 15 minute charging Ray-O-Vac batteries for caching...I can throw them in to charge when I start thinking about heading out, and 2 sets of each size (AA & AAA) are ready before I am.

 

Does anybody else love them? Why or why not?

 

jamie

I was afraid to try one of the fast chargers because i had heard that the high charge rate wasnt good for the batteries and caused them to not be able to handle as many charging cycles. In other words, their overall longevity was cut short if you used a fast charger.

 

Any thoughts on this and what brand automotive type (12 volt) fast chargers would you recommend? Are there batteries specifically made for use with fast chargers?

 

Thanks in advance!

[+Cpt.Blackbeard]

I love the 15 minute charging Ray-O-Vac batteries for caching...I can throw them in to charge when I start thinking about heading out, and 2 sets of each size (AA & AAA) are ready before I am.

 

Does anybody else love them?  Why or why not?

 

jamie

I was afraid to try one of the fast chargers because i had heard that the high charge rate wasnt good for the batteries and caused them to not be able to handle as many charging cycles. In other words, their overall longevity was cut short if you used a fast charger.

 

Any thoughts on this and what brand automotive type (12 volt) fast chargers would you recommend? Are there batteries specifically made for use with fast chargers?

 

Thanks in advance!

I've been using the Energizers with the 15 minute fast charger for about a year now. I take my GPS to work and recharge every other night, and I've yet to see a performance hit on the batteries. Since the Legend takes two batteries and I have four I'd guess that's about 100 chargings per pair so far. The test continues...

[+Miragee]

I love the 15 minute charging Ray-O-Vac batteries for caching...I can throw them in to charge when I start thinking about heading out, and 2 sets of each size (AA & AAA) are ready before I am.

 

Does anybody else love them?  Why or why not?

 

jamie

I was afraid to try one of the fast chargers because i had heard that the high charge rate wasnt good for the batteries and caused them to not be able to handle as many charging cycles. In other words, their overall longevity was cut short if you used a fast charger.

 

Any thoughts on this and what brand automotive type (12 volt) fast chargers would you recommend? Are there batteries specifically made for use with fast chargers?

 

Thanks in advance!

The convenience of getting batteries in 15 minutes is the selling point for me. If my Energizer 2500 batteries only last through 100 charging cycles over a year's time, I'm still money and time ahead.

 

And, since I have had NiCad batteries last me for nearly 20 years, I think my Energizers are going to last a lot longer than a year, even if I use them and recharge them a couple of times a week.

[+NotThePainter]

I had some bad experiences with a Radio Shack fast charge unit. It seemed that the batteries would come of it with barely any charge to run my digital camera.

 

From read around on the net it seems that some chargers shut off after ONE battery is full up. If you're batteries have different amounts of discharge, they'll tend to stay that way, the more discharged ones will not fully charge.

 

The solution is to buy a good quality charger that has a separate circuit for each battery. Mine holds 10 batteries and it has 10 circuits (and 10 LEDs that change from red to green as the batteries charge.) It is also a slow charger and a trickle charger so the batteries can stay in the charger indefinately. (Since NiMH batteries tend to discharge, I think, at 1% per day this is actually pretty useful.)

 

I keep the charger full and my gear empty. I just load it all up when I head out.

[+budd-rdc]

I love the 15 minute charging Ray-O-Vac batteries for caching...I can throw them in to charge when I start thinking about heading out, and 2 sets of each size (AA & AAA) are ready before I am.

 

Does anybody else love them?  Why or why not?

 

jamie

I was afraid to try one of the fast chargers because i had heard that the high charge rate wasnt good for the batteries and caused them to not be able to handle as many charging cycles. In other words, their overall longevity was cut short if you used a fast charger.

 

Any thoughts on this and what brand automotive type (12 volt) fast chargers would you recommend? Are there batteries specifically made for use with fast chargers?

 

Thanks in advance!

The biggest enemy of rechargeable batteries is heat. If the charging current or discharging current is too high, then the resulting heat damages them and diminishes the capacity.

 

Most fast chargers provide charging current low enough not to overheat the batteries while charging, but the critical point is when to reduce the amperage near full capacity to avoid overcharging which usually results in overheating also.

[+GPSOkie]

I use the 2500 mAh Energizer rechargeable batteries and have excellent luck with them. I highly recommend these batteries for and GPSr using AA batteries !

[+OzGuff]

Jenner was the bad rat, and Nicodemus and Justin were good rats.

 

Is this the thread about "Mrs Frisby and the Rats of NIMH"?

[+Team GPSaxophone]

Jenner was the bad rat, and Nicodemus and Justin were good rats.

 

Is this the thread about "Mrs Frisby and the Rats of NIMH"?

I've clicked on this thread twice now thinking it was about a puzzle cache related to that story

[+Wandering Bears]

that was actually in my mind when I posted the thread... lol

[+BigWhiteTruck]

I have the 15-minute Energizer batteries and really appreciate the 15-minute recharging.

 

I also have an inverter for my car, so I can take the charger along and get fresh batteries in only 15 minutes.

 

This is really nice if you are camping, and not driving long distances. Last spring when I was camping at Joshua Tree National Park, I thought I was going to have to go to town and get a motel for one night, just so I could recharge the proprietary battery for my camera and the laptop battery.

 

I wish I could recharge the batteries for those two things in only 15 minutes.

I always think it's funny that people have to take the 12-volt system from their car and bring it up to 120 volts with an expensive device, only so they can plug in some other device that takes in 120 volts only to immediately step it down interbnally to 5 or 2 volts or something.

 

Nothing against you, miragee, it's just funny how products are designed. Like the battery charger should have a 12v input besides the wall plug.

[+Bluejaytoo]

I always think it's funny that people have to take the 12-volt system from their car and bring it up to 120 volts with an expensive device, only so they can plug in some other device that takes in 120 volts only to immediately step it down interbnally to 5 or 2 volts or something.

 

Nothing against you, miragee, it's just funny how products are designed.  Like the battery charger should have a 12v input besides the wall plug.

I agree; that's why I use this one:

 

[+Lone Duck]

I have the first model of that same Energizer charger, works just fine on 12 volts.

 

About the 1.2 volts per NiMH AA that the origional poster asked about - that's perfectly normal with NiMH batteries. You won't have problems with devices that use them.