Preferred Charger and rechargable batteries

[+Roadlover]

I just ordered a Garmin Oregon 400t and can't wait to get started. I've found a few caches with a barrowed gps unit but looking forward to having our own. But I have a question about batteries, particularly rechargable batteries. What kind of batteries do most people use in their gps units. Alkiline, lithium or rechargeable? And for those who use rechargable, what is the best battery and best kind of charger? I'm sure over the next few weeks I'll be asking a bunch of questions but that is one I was just thinking of for the time being. Thank you

[+Jeep4two]

Here are two great threads on this topic:

 

Here in this forum: http://forums.Groundspeak.com/GC/index.php?showtopic=221262

 

Over in the Technology Forum: http://forums.Groundspeak.com/GC/index.php?showtopic=220993

 

Basically - a quality charger is a must, one that discharges some believe to be better for conditioning and extending the life of NiMH batteries, and go with high mAh ratrings. Some also love the new low discharge NiMH batteries since they don't lose their charge while just lying around quite so badly as regular NiMH batteries.

[+jeffbouldin]

Black 1968

[+mty55]

I've been using a MAHA MH-C9000 charger and Powerx 2700ma batteries since I bought my Oregon 300. The chargwr and batteries have worked out great batteries hold a charge very well and charge up pretty quick even when I charge @ the 500ma setting. Overall I think its a good setup.

 

 

http://thomasdistributing.com/shop/charger...usnltk7megnug91

[+Gryffyth]

I use a La Crosse BC-900 charger, 4 La Crosse 2600mA AA Rechargeable and 4 eFilm 2500mA AA Rechargeable.

 

http://thomasdistributing.com/shop/la-cros...pscjsktk1b6cm70

 

-Gryffyth

[+DonB]

I use three different MAHA chargers, and I would recommend the hybrid NiMH rechargables. I have mostly Sanyo Eneloops and the ones made by Kodak.

[NordicMan]

I've been running the Sanyo Eneloops for quite a while,, GREAT batteries!

[+Eagle93]

I also use the Sanyo Eneloops and so far am very impressed. A higher mA rating would be nice, but the 2100 mA Eneloops work for me.

[+Curioddity]

I also use the Sanyo Eneloops and so far am very impressed. A higher mA rating would be nice, but the 2100 mA Eneloops work for me.

I've been very involved in the model aviation (R/C) hobby for many years and that hobby tends to stay on the bleeding edge of rechargable battery technology. LiPo (Lithium Ion Polymer) and LiFePO4 (Lithium Ion Nanophosphate) are typically our cells of choice for high-output applications like spinning props, but we also use lots of NiMH packs in our transmitters and as receiver packs in unpowered planes like slope and thermal gliders.

 

The general consensus among the genuinely knowledgeable people in that hobby is there is a "sweet spot" for AA-sized NiMH cell capacity and it seems to be around 2000 - 2300 MAh. Go above that and the cells don't last for as many charge-discharge cycles before they begin to suffer from high internal resistance and other problems. Simply put, it's the penalty one has to pay for the high energy density.

 

I fly more slope gliders than powered planes and many (like the one in my avatar) are made of EPP foam which is reinforced with carbon fiber and covered with strapping tape and iron-on film. Most of these type of planes are built with AA-size NiMH receiver packs imbedded in the foam and covered over with the film and tape (we charge them in-plane through a switch-jack). If the pack goes bad, we have to cut the plane open to replace them.

 

I initially used the highest-capacity cells I could find which was around 2400 MAh when I started and eventually hit the ~2700 MAh ceiling we see today. To make a long story short, I've had to cut nearly every one of those planes open and replace the packs because most were suffering from unacceptably reduced capacity after a couple of seasons of flying. I should add that I used top quality industrial cells from Sanyo and programmable multi-chemistry chargers that most of you would deem absurdly expensive.

 

But every plane I built with 1800-2100 MAh cells in them are still going strong and many of them are 5+ years old. Because of this experience, I quit buying AA NiMH cells over 2100 MAh and since Sanyo released the Eneloops (the model aviation crowd knew about them long before the general public did), I've used them exclusively.

 

Anyway, the bottom line is there is an added price to pay for cells with the high energy densities (over ~2300 MAh): You'll have to replace them more often. After about a year of regular use, they'll often have the same usable capacity as 2000 MAh cells and it goes downhill pretty quickly after that. The lower capacity cells will typically outlast them by a significant margin, often measured in years.

 

And for what it's worth, if you want to see that plane in my avatar in action over Point Fermin in Southern California, visit http://www.vimeo.com/1760099. That's my other obsession

 

Pete

Edited May 29, 2009 by Curioddity

[+Roadlover]

I want to thank everyone for your help. Your advice and the links gave me some incredible information. I ended up ordering a LaCrosse BC-900 charger from Thomas Distributing, which was on a special for $34.97 and included 4-2600 mA AA Batteries and 4-1000 mAh AAA batteries. Hopefully it was a good deal. Again, thanks for all your help!

[+Kohavis]

I have three sets of (2)Energizer AA NiMH I rotate for use in my Venture HC:

 

(2 sets) 2500 mAH

(1 set) 2000 mAH

 

Charger is the bubble-pack Energizer CHVC2 charger that came with the (2) 2000 mAH batteries.

 

Charging time:

 

2500 mAH - 16 hours

2000 mAH - 12.5 hours

 

I start the charger the afternoon before my next caching hunt. The batteries last for even the longest hunt without any drop in the # of bars of the charge indicator.

 

Before the next hunt I rotate in the next charged set and drop the old ones into a discharge box I built to completely discharge them.

 

This system has served me well

[the3gmen]

Is it better to top the batteries off after a day of use, or continue using them until they are closer to fully discharged ?

[jholly]

Is it better to top the batteries off after a day of use, or continue using them until they are closer to fully discharged ?

 

NiMH batteries do have a small memory effect, so discharge is best. But if you get a Maha or Lacrosse charger you can program the chargers to discharge before charging so that is not an issuer with those chargers.

 

Jim

[+Chrysalides]

Is it better to top the batteries off after a day of use, or continue using them until they are closer to fully discharged ?

In addition to what jholly said, I find it more convenient to carry an extra set (or 3) of low self discharge NiMHs with me, and replace them only when the set in the GPSr is depleted. Remember that the cells have a finite # of charge / discharge cycles in them.

[+Wild Thing 73]

alkaline batteries discharge only when using. rechargeable batteries start discharging immeditly and can drop dead anytime without warning...Alkaline will give you you a warning when need replacing.I have used both, but prefer the alkaline....simple, no recharging time and they last about 18hours, which is a lot of caching. I carry pockets full of alkaline batteries. I will never have my GPSr run out of battery power. stay Safe.

[jholly]

alkalines will also self-discharge over time. Rechargeables don't drop dead at a moments notice, they discharge just like alkaline batteries. The charge indicator on most GPS's will show this if you have the system set to NiMH instead of Alkaline. Pockets full of alkalines cost far more than four rechargeables and a charger, plus you don't have near the disposal problem, unless of course you just chuck them into the garbage and load the land fill with heavy metals. My rechargables last over 12-14 hours which is a lot of caching.

 

Jim

[+Chrysalides]

NiMH are cheaper and more environmentally friendly. Carry a spare set of lithium AA around if you like for emergencies. The NiMH hybrids have very low self discharge rates.

Edited May 31, 2009 by Chrysalides

[NordicMan]

alkaline batteries discharge only when using. rechargeable batteries start discharging immeditly and can drop dead anytime without warning...Alkaline will give you you a warning when need replacing.I have used both, but prefer the alkaline....simple, no recharging time and they last about 18hours, which is a lot of caching. I carry pockets full of alkaline batteries. I will never have my GPSr run out of battery power. stay Safe.

 

That's the beauty of batteries like the Sanyo Eneloops, they have a very low "self discharge" rate. Charge 'em up & stick them in the GPSr & put both in a drawer for a few months. Pull them out & they'll still have a decent charge! Also they might have *some* memory effect but NOTHING like the horrible NiCads used to have!!!

 

Personally I throw my Eneloops into the charger whenever I'm about to use them, no matter what their current charge rate is. I refuse to leave the house with anything less than FULL batteries, and I really don't feel like carrying a pocket full of spares. Call me lazy but, hey what year is this anyway? Batteries aren't the boss of me

 

..and I think the tree huggers appreciate my rechargables are making the world a bit more greener

[+Maingray]

Same as Nordicman.

 

For my Oregon, I prefer to use Eneloops. They last a long time.

[+Curioddity]

Is it better to top the batteries off after a day of use, or continue using them until they are closer to fully discharged ?

Quality NiMH batteries made these days don't really suffer from the crystal formulation in the cell chemistry like older cells did. In addition, NiMH cells never suffered from it like NiCd cells did and it was NiCd cells which propagated the need to discharge cells completely before recharging them. I should also mention that crystal formation in the cell chemicals is what causes "voltage depression" in Nixx cells and voltage depression is what is commonly but incorrectly known as "memory" in rechargible cells.

 

But as I mentioned, modern manufacturing techniques and improved cell components have almost eliminated the problem of crystal formation in both NiMH and NiCd cells alike which has reduced the "memory" problem to a level we can safely consider insignificant. If you are using a quality brand of rechargible cells you might want to do a full discharge - charge cycle once a month at most and 3-4 times a year will actually do.

 

As for topping the batteries off after a day of use, unless you are using the new hybrid (low self-discharge) cells you're better off topping your batteries off just before you use them rather than after. Standard NiMh cells can lose up to 20% of their charge in 12-14 hours if they're in a warm enough environment. The self-discharge rate is dramatically accelerated by warmer temperatures so it's important to give some thought to where you carry your spare cells while you're out caching. For example, it's not a good idea to keep them in a solar oven like an outer pocket on a dark-colored daypack or bicycle pack.

 

On a final note, you should never completely discharge NiMH cells. Discharging them below 0.9V per cell will do irreversible damage to the cell chemistry which typically results in reduced energy density (capacity) and a significant reduction in the number of charge-discharge cycles you will get from them before you'll need to replace them. Also, heat is bad juju!. If your NiMH cells are getting hot in the charger you're damaging them. Warm is OK but hot is not! It's normal for NiMH cells to get warm at the end of a charge cycle but if they get hot, you're either charging them at too high of a rate or you're overcharging them. Rapid chargers (1 hour or less) may sound appealing, but the truth of the matter is that charging at that rate significantly reduces the service life of the cells and that's not something you'll read on the package the charger came in.

 

The best chargers for NiMH cells are delta-peak chargers (also known as peak-detect or "smart" chargers) which will charge your cells in 2-3 hours rather than 1. This type of charger will detect when the cells are fully-charged and either stop charging or switch to a "trickle" mode. I've found that the MAHA MH-C800S in "Soft Charging" mode does that quite nicely. I'm sure there are other loose-cell chargers that will too, but I can't recommend what I haven't tried.

 

If you'd like to truly understand the science of rechargable battery charging, use, and maintenance, check out the following link:

 

http://www.batteryuniversity.com/index.htm

 

Pete (with one of my NiMH-powered $1000+ carbon composite reasons to really understand battery maintenance)

 

Edited May 31, 2009 by Curioddity