Confused about rechargeable batteries?

March 24, 2003

Anyone have words of wisdom in regards to choosing rechargeable batteries for my Garmin GPSMAP 76S? It gets very confusing when looking at all for offerings off the web. I see AA batteries of Nickel Metal Hydride (NiMH)with 2000, 1850, 1700 and even 1200 mAh. The higher the number the higher the price. I know this has been covered in the past, but has anything changed in the past year or two? I found a web site that offers the Kodak rapid charger that will handle 1 to 4 batteries, AAA and AA, plus, 4 AA at 2000 mAh and 4 AAA at 700 mAh for about $36 with shipping. Is this about right? Is the Kodak charger a reasonable unit? Thanks!

EricGPS

2.4k · March 24, 2003

The higher the number of mA-hrs, the longer you should be able to operate your 76S per charge. My eMap draws a current of about 150 mA, therefore using 1800 mA-hr NiMH cells I can operate it for about 12 hours (1800/150) per charge. Usually there's a sizable price premium for the latest high capacity cells - currently around 2000 mA-hr. The ones with just a little less capacity (around 1800 mA-hr) are generally more cost-effective. It's a good idea to have a spare set of cells along just in case you're out longer than expected or the first set of cells wasn't as fully charged as you thought.

I'm not familiar with Kodak's charger. I use Ray-O-Vac's 1-hour charger at home and Maha's C204F 4-hour model in the car. Both sense when the cells are charged and switch to a trickle-charge mode. I've been happy with the performance of both of these chargers although some people had problems with the earlier version of the Ray-O-Vac getting the cells too hot.

5.3k · March 24, 2003

A charger that can sense the state of the batteries and has tha capability of keeping the batteries cooler will offer longer battery life. I think any changes over the past year that I have seen have been mostly in the chargers.

I'm not familiar with the Kodak, but this is the one I would buy today. It's a little more money, but when you consider how much you save over the life of the batteries, I view it as an investment that pays for itself. Don't scrimp here.

Max

Often wrong but seldom in doubt

March 24, 2003

Embra is right, get the MH-C401FS. It is the lastest in charger technology. I have three differnet chargers and this one is by far the best. You can buy it in a package with 4 2000mAh Powerex batteries. They are the best batteries out there. Check out this battery test/review site called the great battery shoot-out:

http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM

The charger/battery combo can be found at the bottom of the page Embra linked to above.

March 25, 2003

Thanks for the battery info website. This is my type of reading material!

Thanks again,

EricGPS

March 25, 2003

Go to RS and get a $ 20 charger with two 'free' batteries and buy a spare set at $ 10. More if you like to stock up.

No matter how little you spend on a rechargeable set, it will save you money in the long run. As in a few days of caching...

Quality... I am not an engineer, but it stands to reason more is better.

Never underestimate the stupidity of people in large groups.

March 25, 2003

BatteriesAmerica.com has 2000mAh NiMH (Nickel Metal Hydride) batteries at a reasonable price. These are the highest capacity AA rechargeables available. I use them in my GPS's and in my Ham HT's; they have no memory effect, can be charged very quickly without damage, and have a nice, level voltage output until exhaustion.

Oh, and YOU, Scott Johnson ... you must be the one who's been giving me a bad reputation! Or is it the other way around?

Scott Johnson (no, the other one.)

--

Scott Johnson (ScottJ)

March 26, 2003

They loose charge just sitting much faster than conventional batteries.

This can be a real problem in an emergency. It's not fun to find your back-up set has a fraction of the charge you were expecting. It's like carrying a leaky spare tire in your car.

Conventional batterie, however, have a very long shelf life. The expiration date for batteries I'm buying now is 2009!

I got tired of the management hassle of keeping track of all the rechargable batteries...GPS, FRS, Flashlight, Camera, Caving Lights...and other techo-gizmos I take with me out in the wilderness. I finally gave up and I am now using disposables exclusively. I know that's not eco-friendly, and not the cheapest way to go, but I find my devices much more reliable now.

I guess what I'm saying is that you should, at least, always carry a set of conventional batteries for emergencies. It sure beats finding your spare rechargables are dead.

George

March 26, 2003

I'm a little confused on the runtime of NiMh rechargeable batteries. Some say there is less runtime on rechargeables than alkalines but reading the posts on candlepower they say a rechargeable is more efficient internally so it gives out more of it's power. Alkalines are inefficient internally so the lower they get the less of the power that's left is usable (if that makes sense). Think I'll post out there and get a definitive answer.

2.4k · March 26, 2003

Part of the confusion comes from the different behavior of alkaline cells vs. NiMH/NiCd depending on the amount of current required. NiCd and NiMH cells have relatively low internal resistance and can efficiently deliver very high currents. This is important in devices like cameras and flash units which don't operate for long periods of time but draw a large current when they are on. OTOH, alkaline cells have more internal resistance and are better at delivering their full capacity at low currents for longer times. They also don't deteriorate nearly as fast while sitting idle - alkalines will retain most of their charge for 5 years under reasonable storage conditions while NiMH cells retain that much of their charge for only 3 - 6 months (less after many charge cycles).

A rough comparison of capacity vs. current draw of the two types looks something like this:

Current Alkaline NiMH

20 mA 2700 mA-hr 2000 mA-hr

100 mA 2200 mA-hr 1950 mA-hr

200 mA 1700 mA-hr 1900 mA-hr

1000 mA 600 mA-hr 1800 mA-hr

Most GPS receivers draw around 100-200 mA, so the runtime per charge is similar for alkaline and good NiMH cells. Many digital cameras are up in the 1000 mA range and perform much better with NiMH cells.

BTW, the 'great battery shoot-out' article cited by Daddyfish was done using a current of 1000 mA and the results may not apply at the much lower currents used by GPS units.

March 26, 2003

Peter,

Thanks for the info/chart. It shows what my conclusions are from candlepower. If the runtime is essentially equal and they're rechargeable then it's the way to go. Figure if I get the Maha I can charge on the go if needed. Not concerned with the deterioration over time since I'll just be looking at maybe a week away from the charger camping.

March 26, 2003

Here is what I did. I bought a small 12 Volt sealed lead acid battery (SLA) and a smart charger for it. I put a cord end on it so that I can plug my GPS into this battery same as in the car.I carry the battery in a small fanny pack which has an area above the battery to store my GPS when not in use. Makes for a nice arrangement. The battery is about 3 x 5 X2 inches and can run my GPS315 for 36 hours staight. When at home just leave it on the smart charger. Once can get smaller SLA's, but I opted for this one because it will get me through a week hike without worrying about batteries. Another nice thing about this arrangement is that I can use it for most anything I plug into the cars lighter socket.

P.S.

The key to long life on this and other recharagable batteries is having a smart charger.

5k · March 26, 2003

quote:
Originally posted by marfo:
I carry the battery in a small fanny pack which has an area above the battery to store my GPS when not in use. The battery is about 3 x 5 X2 inches and can run my GPS315 for 36 hours staight.

I like that idea, but lead batteries are not light. What does this thing weigh?

Jamie

5.3k · March 26, 2003

quote:
Originally posted by marfo:
Here is what I did. I bought a small 12 Volt sealed lead acid battery (SLA) and a smart charger for it.

That's fine, but I hope you know that you would get exactly the same lifetime for one-third the weight with a 4V battery.

5.7k · March 26, 2003

quote:
Originally posted by nincehelser:
They loose charge just sitting much faster than conventional batteries.

This can be a real problem in an emergency. It's not fun to find your back-up set has a fraction of the charge you were expecting. It's like carrying a leaky spare tire in your car.

Conventional batterie, however, have a very long shelf life. The expiration date for batteries I'm buying now is 2009!

This is a very poor argument against rechargables. My solution for this is to buy one set of conventional batteries for those emergency cases. If I ever have to use them I buy a new set to replace them. In the 9 months since I started using rechargables I've only had to buy one new set (read: two AA batteries). When you are caching every day, you recharge every day. It doesn't take a lot of thought process to plop them into the charger when you get home and put them back in the next time you go out.

My record for the number of cache finds on one charge is 46.

If I hadn't been using rechargables (I bought 4 1850mh energizer batteries at Target), I would have used a staggering number of conventional AAs (if you figure one set every two days, it comes to over 200 batteries I would have used). I think I came out ahead.

--Marky

"All of us get lost in the darkness, dreamers learn to steer with a backlit GPSr"

March 26, 2003

Like I said, I carry around lot of battery powered gear. I'd have a whole lot of recharging I'd have to do every night. I just don't need that much battery management complexity.

First thing I do when I look at new gear is ask "Does it run on AAs?".

Besides, deep in a cave is *NOT* the place to find your batteries are not up to snuff.

George

2.3k · March 26, 2003

The advantages of using these are many. You can run many devices that have cig lighter plugs with these. I run cell phone, handheld radios, lanterns, TVs. In fact, it will charge the rechargeable batteries on these items. Also, you can easily charge the gell cell in your car by plugging it straight into the cig lighter socket. They come in lots of sizes.

March 30, 2003

quote:
Originally posted by EScout:
The advantages of using these are many. You can run many devices that have cig lighter plugs with these. I run cell phone, handheld radios, lanterns, TVs. In fact, it will charge the rechargeable batteries on these items. Also, you can easily charge the gell cell in your car by plugging it straight into the cig lighter socket. They come in lots of sizes.

This is starting to sound like a workable plan. Can you describe the setup and any specific parts?

Think I can still get free hospital gellcells, which must be replaced at specified service intervals, even if they are still good.

"There's no need to be afraid of strange noises in the night. Anything that intends you harm... will stalk you silently."

March 30, 2003

There is a 12-volt gel cell pack offered by Laerdal, complete with female lighter plug output and soft case; it is used with some of their Automated Exteranl Defibrillator training systems. I believe it sells for less than $80.00, but am not certain of the part number. It can be charged from any 12VDC source

If I can get a chance to look at one, I will pass along the information. If anybody here is into EMS training and has one of these battery packs, please chime in with the info.

I Roger your vector, Victor...... Over.

2.3k · March 30, 2003

Gell Cell

All of my gell cells are wired with a molex plug. Other devices, charger, cig lighter receptical have the opposite plug. You can charge it at home with just about any wall wart marked 12V DC, because they are usually unregulated and have a higher voltage under no load.

Plug the cig receptical to the gell cell and you have a large supply of 12V DC to run other devices (that have voltage requirement of less than 12V) Rig it to recharge directly from your car's system while the engine is running.

March 30, 2003

I bought a Radio Shack 13 hr Ni-Cd/Ni-MH Charger which came with 4 1.2V 1500mAh AA batteries (green) for $22. When I bought an additional 4 batteries, it was $18. Go figure. I've used them in my digi cam, FRS/GMRS radio and GPS with no problems. I've bought a couple of additional sets, too, and yes they do get warm after being charged.

WHERERWEGOING

March 31, 2003

Just picked up four more NiMH batteries (Energizer 1850 mAh) for under eleven dollars at the nearby "AL-MART" (the "W" was not illuminated). These should keep my GPS and digital camera going for a while.

I Roger your vector, Victor...... Over.

March 31, 2003

I initially bought four 1800 mah Rinpochce batteries and a charger for $9.99 at WallyMart. Since then, I have since purchased the same thing again, and then another eight 2000 mah batteries from ebay for $9. (Let's not turn this into a pro/con ebay discussion).

All told, I have $29 invested, and a total of sixteen batteries. They work great in my handheld police scanner, and my GPS.

This past weekend, I took two batteries that had been sitting charged, and got just over nine hours use in my Legend before the low battery indicator appeared. So, I popped in two more I had in the truck.

16 Alkaline batteries would have cost me about $12 or more, so I am already way ahead of the ballgame.

Here are some 1800 mah batteries to look at. Very reasonable.

Enjoy! I think rechargeables are the only way to go. Keep some Alkaline in the bag "just in case", and a lighter adapter too...and you can't go wrong.

OUT!

Counter Fit Cache

...or is it really me????

April 1, 2003

I wish this thread were here before I sent my order in for the Kodak charger and batteries! Live and learn I guess. The charger I received has the Kodak name on it but it is a model 200D, NOT 2000D that I wanted. The 200D seem to just have a timer that controls the charge duration of 8 hours. With a charge rate of 220 mahr by my calculations means they only charge to 1760, not the 2000 of the battery rating. The 2000D is a smart charger with 3 hour charge rating, and it will charge from one to four batteries at a time. The 200D require two of the same size batteries to charge. I screwed up and just wanted to warn any one else to really check the model of what you might be ordering. Wish I had!

April 1, 2003

After reading this thread and some online researching I went to Walmart and bought Rayovac 1-hour charger (Model PS4) - all I can say - I really like it. Plus the car adapter is really handy.

.... and yes, it supports trickle charge :-)

April 3, 2003

I just got back from where a couple of the batteries that I previously described were located. They are actuall sealed lead acid batteries and were marketed by Laerdal as the "Heartstart Training Battery" about six years ago. Not sure if they even offer such a thing now.

Upon opening the zippered case containing the battery, I found a part number from Alexander that is GB1270 (12 VDC, 7.0 AH). The battery has male spade terminals on top and should be easy enough to maintain and charge.

Batteries.com lists something just like this for a reasonable price, and an adapter cable (with female spade lugs on one end and a female lighter plug receptacle on the other) could be easily assembled. The only other part would be to come up with a case which could fasten to the operator's belt or fin in a backpack or "fanny pack" pouch. With a 7.0 AH capacity, a GPS (and maybe something else) could be run all day .

I Roger your vector, Victor...... Over.

April 3, 2003

quote:
Originally posted by nincehelser:
"...Like I said, I carry around lot of battery powered gear. I'd have a whole lot of recharging I'd have to do every night. I just don't need that much battery management complexity..."

Not to beat a dead horse or anything, but you could probably save yourself a ton a'dough in AA alkalines (not to mention your trips to the store to buy them) *without* an unwieldy amount of hassle when it comes to recharging NiMHs. If you use several pieces of battery operated equipment at a time, why not purchase three AA(x4) NiMH smart chargers - the kind that allow you to leave the batteries in them and 'topping up' indefinitely - and have 12 AAs ready to go 'fresh out of the charger' at any time? Since NiMHs don't suffer from memory effect, there's no need to fumble over which batteries should or shouldn't go back into the chargers at the end of the day ...just put them *all* in - whether they've been used or not - and be good to go again when the charging cycles are complete. Although I agree that keeping a 4-pack of standard alkalines on hand 'just in case' is probably a good idea, even the most battery hungry gadget freak should be hard pressed to eat through a dozen 2000mAh NiMHs in a typical day (...x2 GPS, x3 FRS, x4 DigiCam, x2 flashlight?). In fact, from a cost point of view, the more battery operated devices that you use (and you seem to use quite a few), the less sense non-rechargables make. If you're a frequent battery user, it wouldn't take you long to recover the cost of a good set of NiMHs and a charger (...or two ...or three) from what you would be saving yourself in disposable alkalines.

1.3k · April 9, 2003

I just purchased a Ray-o-Vac universal charger for $20 bucks. I'll admit I didn't do any research before I purchased this, but I haven't opened the box yet and I have the reciept and wally-world is usually forgiving on returns so... Would it be a better idea to return this one for the 1 hour charger?

I purchased this one because it has the ability to charge AAA, AA, C, D, & 9v batteries.

Does anybody here use C, D, or 9v rechargeables?

The longer time isn't a problem to me, but I'd save 10 bucks

Is Ray-o-vac a good charger? How about their batteries, or are all rechargeables (of a certain type, say NiMH for example) the same?

SD

April 10, 2003

Hi,

I've got an older:

Radio Shack 5 hr Ni-Cd/Ni-MH Charger. I've been using it with some AA Ni-MH 1200mAh batteries. I'm interested in picking up some 2000mAh batteries... can I use the same charger?

(Sorry if it's a stupid question)

Thanks,

Pete

Edit:

I found the pdf on the unit... does this mean I can or can't DOH? http://support.tandy.com/support_electronics/doc62/62556.pdf

April 10, 2003

Actually, I don't think I'd save all that much...at least not enough for me to really care.

For example, I figured in another thread that it would take me nearly a year to break even with rechargables for just geocaching...and when I did finally break even, there wouldn't be much left to geocache within a 100 mile radius. Yearly geocaching cost for disposables would be $30 in my case. Not enough for me to worry about the cost (it pales in comparison to gas money for caching, for example).

Rechargables for caving are out. I just don't trust them. Plus, they'd get awfully ugly being drug through water and mud. I doubt if they would last long under these conditions (let along transferring grit to my other gear and charger via dirty batteries).

Given this, it's just is a whole lot easier to buy disposable AAs in bulk and use them where needed. That way I'm sure of my power levels and I don't have the recharging hassle.

The bottom line is that rechargables just don't seem to make a lot of sense for me.

George

April 10, 2003

Ok, so I'm paranoid that my post before nincehelser's is gonna get lost.

^ Pete

April 10, 2003

I read the PDF, thanks. It states at the top of Page 4 - "Do not try to charge batteries other than those listed in this manual..." I also noticed it topped out at 1100 mAh for AA batteries (Pg.5).

It may have been a dandy of a charger in it's time, it may however be time to get a newer one capable of the 2000 mAh - but now they've got 2100's and 2200's - when do you jump in? I ordered a MAHA charger and 8 batteries of the 2000 mAh type - the charger may not be able to handle the 4000mAh batteries coming out next year - just kidding - nothing above 2200 personally seen.

The newer chargers are made to keep the batteries cooler while charging, they prolong the useful life of rechargeables and they handle more powerful batteries. I'm not selling them to you, just think you might consider them.

Worst case scenario? Battery or charger meltdown, house burned to the ground, neighborhood caught fire and you are liable for the insurance deductible. Slightly bad scenario? Unpredictable charging of the higher mAh AA's. I would most definitely NOT try it at home.

OddTodd

April 14, 2003

Now that I have my rechargeable AA, 2000 mAh batteries and started using them in my Garmin GPSMAP 76S, I find I have more confusing thoughts about what the heck is going on!

Let me start with saying that they seem to work ok, however, if you look at the battery level in the main menu it shows the fully charged battery less then full. Am I doing something wrong? Is there something in the GPSMAP setup to tell it I’m using Nickel Metal Hydride (NiMH)? I understand that the NiMH have 1.2 instead of the 1.5 volts. Is this the reason for the less then full indication?

Thanks!

5.3k · April 14, 2003

quote:
Originally posted by Ericgps:
Now that I have my rechargeable AA, 2000 mAh batteries and started using them in my Garmin GPSMAP 76S, I find I have more confusing thoughts about what the heck is going on!

Let me start with saying that they seem to work ok, however, if you look at the battery level in the main menu it shows the fully charged battery less then full. Am I doing something wrong? Is there something in the GPSMAP setup to tell it I’m using Nickel Metal Hydride (NiMH)? I understand that the NiMH have 1.2 instead of the 1.5 volts. Is this the reason for the less then full indication?

Thanks!

I'm not familiar with your particular unit, but SOME units do have a setting for battery type. Unfortunately, my Meridian does not

"Just because I don't care doesn't mean I don't understand."

April 14, 2003

Ericgps,

My Rino has a setting for NiMh batteries and changed it from alkaline when I put my 2000mah Powerex's in. Not sure if it just changes the battery meter or possibly in addition changes the shutdown warning. I kind of look at it like my gas guage in the truck. After you run through a few tanks you know when the guage means you're REALLY empty. My Rino works just as well if not a little better on NiMh than alkalines.

April 14, 2003

quote:
A rough comparison of capacity vs. current draw of the two types looks something like this:

Current Alkaline NiMH

20 mA 2700 mA-hr 2000 mA-hr

100 mA 2200 mA-hr 1950 mA-hr

200 mA 1700 mA-hr 1900 mA-hr

1000 mA 600 mA-hr 1800 mA-hr

Most GPS receivers draw around 100-200 mA, so the runtime per charge is similar for alkaline and good NiMH cells. Many digital cameras are up in the 1000 mA range and perform much better with NiMH cells.

BTW, the 'great battery shoot-out' article cited by Daddyfish was done using a current of 1000 mA and the results may not apply at the much lower currents used by GPS units.

THIS PAGE seems to jive with that. Alkaline batteries tend to last longer in low-draw applications.

It also occurs to me that if rechargeable are sensitive to impact (such as dropping) you might not want to use them in a rugged environment. I drop my GPSr (eTrex Legend) occasionally. It's a very hearty unit and has had no ill effects from the impact, but put in some drop-sensitive batteries and...

1. You might think you just busted the GPSr. More importantly...

2. You might end up in the field with no navigation.

Given this discussion and all the links to external info, I'd stay with alkaline for your GPSr and use the NiMH for the camera (which is drop-sensitive regardless of the batteries).

April 14, 2003

quote:

It also occurs to me that if rechargeable are sensitive to impact (such as dropping) you might not want to use them in a rugged environment. I drop my GPSr (eTrex Legend) occasionally. It's a very hearty unit and has had no ill effects from the impact, but put in some drop-sensitive batteries and...

1. You might think you just busted the GPSr. More importantly...

2. You might end up in the field with no navigation.

Given this discussion and all the links to external info, I'd stay with alkaline for your GPSr and use the NiMH for the camera (which is drop-sensitive regardless of the batteries).

I use rechargeables in my Legend, mounted on the top of my ATV. I ride hard, fast, and across some hellacious terrain, not to mention getting awfully wet (usually) and muddy (always). No problems with "impact" issues. Just recently, I put a fresh set of AA batteries into my Legend at 9 AM, ran it all day long, and got a "low batt" indicator around 6 PM. 9 Hours of constant use, and popped in a set of rechargeables...and good to go into the night. Turned the unit off around midnight. Worked fine the next morning for another two hours.

Anyway, I have luck with 'em. And, I have not bought batteries for over three months now....all for a $30 investment. Seems to work for me.

OUT!

Counter Fit Cache

...or is it really me????

Confused about rechargeable batteries?

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