Any luck with rechargeable batteries? Not here.

Well one factor is that there are different kinds of rechargeable batteries.  They should give an milliamp-hour rating on the battery, for example 2000 mAh or 2700 mAh.  Generally speaking, the larger the rating the better the battery. 

I've tried a bunch of different kinds and I think the best are the Sony 2700 mAh NiMh AA batteries.  If you just do a search for 'Sony AA rechargeable 2700' you should be able to find them.  I got them on Amazon.  They also make a nice charger for them if for some reason yours isn't compatible.

I think there is an older thread here on greenhome.huddler regarding rechargeables also.

I have many Energizer rechargeables, the family charger, 15-minute charge, and compact charger as well.  I do not have any D or 9v size, but I DO have C, AA, and AAA.  I have had - actually - very good luck with them.  We use them mostly in our kids electronics and flashlights, plus we have a number of hockey-puck style LED lights under cabinets, in closets, etc. that we use the AAAs in.  Overall we are happy.  Every couple of months I do take some time to charge all of the batteries whether they seem low or not... which I don't mind doing - but others might.

One note - the original 900mAh AAA NiMh Energizers I got I found to not last in my pager.  The newer 850mAh AAAs, which are supposed to last significantly longer have done well.  (The AAs are around 2450mAh).  The technology is getting better all the time and if the newer line continues to perform - it's really a big and positive improvement.

If you have one bad battery in the set you are using in a device, it will underperform.  This might be your problem.  A charger that can do a stress-test would show you if this is the case - but that's around US$60.

The enelope line of rechargeables are supposed to be good, along with MAHA brand (which I have only seen available on-line).  MAHA is also supposed to have some great chargers you can use with any NiMh types and it will stress test them to see what their actual mAh rating is.

Recently, NiMh is getting more popular than NiCd. It is important to know which one you have.

One most significant difference betwee these two rechargable batteries is Memory Effect. When you use NiCd, you must first charge full, then use until it dies. This stupid battery always remembers the time it was charged, and memorise it as the empty level. So, if you charge half used, battery memorisez half way is the empty level. You will significatly reduce the capacity. Since NiMh does not have such memory effect, you can charge anytime you want. The charging characteristics are also different for them. You must pay attention which one you are charging. The universal charger has a selector switch.

I think, however, rechargable battery is desined to provide large current for shorter time, rather than small current for long time. I am quite sure it has much higher self discharge rate than reguar alkaline battery, which normally stays fresh for 3 years. If you use batteries for those gadget you do not use frequently and for long time, you may not be able to expect the same results as regular alkaline batteries.

I would not recommend rechargable batteries for emergency equipment that will be kept for extended time without use. Regular alkaline battery will be the best for the application, because it will stay fresh at least 3 years when it is left unused.

Again, the best use of rechargable (whichever NiCd or NiMh) is for large current and short time.

The Sony CycleEnergy NiMH cells are rebadged Sanyo Eneloops and others may start to sell them as "hybrid" cells.  In this case, "hybrid" means a cross between rechargables that used to need charging before use and ordinary cells that are ready to use from the pack but are disposable.

Both are a new type of NiMH with very low rates of self-discharge, a historic problem with NiMH cells.  NiCds cells don't suffer from self discharge so much but do suffer from memory as mentioned.

I've used the Sonys in mice and other low power kit and they last a lot longer between charges (like a couple of months).  I've got some old Sanyos (before they changed to Eneloop) that are terrible.  They go flat by themselves in a few days.  I use them in a flash gun that uses a lot of power in one day.

Not all "traditional" NiMH cells are so lossy though... I've got some Uniross 2300 cells in my shaver and they last for weeks using them a few minutes a day.

You can tell which are the new "hybrid" cell packs by the fact that they are described on the pack as "ready to use".  This is because they are charged at the factory and can retain their charge (to 70%) for up to a year on the shelf.  Of course, in the future if you are unlucky enough to buy some old ones from a shop, they might be dead.  But at least unlike out of date alkalines, you can always give these hybrid cells a charge and they'll be good to go.

Technologies progress so fast that easily empties our wallet. I do not own it, but the new NiMh hybrid sounds very good. A problem is I spent too much for the rechargables with chargers, and cannot dispose them until I wear them out.

Quote:

Originally Posted by SoCalSolar 

 

The enelope line of rechargeables are supposed to be good, along with MAHA brand (which I have only seen available on-line).  MAHA is also supposed to have some great chargers you can use with any NiMh types and it will stress test them to see what their actual mAh rating is.

I use the MAHA Imedion Ultra-Low Discharge NiMH batteries (both AA and AAA) with very good results.

I've found Thomas Distributing to be a good supplier of those batteries:

thomasdistributing.com/shop/advanced_search_result.php

Since they use a new technology that siginifcantly decreases internal self-discharge rates, they claim to remain as much as 85% charged after one year of non-use, whereas most NiMH rechargeable batteries would only have about half their charge left ( en.wikipedia.org/wiki/Low_self-discharge_NiMH_battery )

I use this charger:

MAHA MH-C9000

which, as part of charging or discharging a battery, keeps track of the energy in/out, and at the end of the charging/discharging, will tell you the battery's capacity.

Keep in mind that such batteries (even the normal NiMH technology) need a few charge/discharge cycles before their full capacity can be used (no link handy to back this up but searching should easily find some mention of this).

Another good source for both information and products related to rechargeable batteries:

www.steves-digicams.com/nimh_batteries.html

Beware of so-called "quick chargers", trying to charge a battery too fast can decrease its life expectancy.  I always use the lowest setting when recharging my batteries, since I'm in no hurry, having enough previously-charged batteries ready to go when needed.

Quote:

Originally Posted by bobkart 

 

Beware of so-called "quick chargers", trying to charge a battery too fast can decrease its life expectancy.  I always use the lowest setting when recharging my batteries, since I'm in no hurry, having enough previously-charged batteries ready to go when needed.

Some hybrids don't like being used in the fastest "15 minute" chargers but all are ok in the older "60-90 minute" fast chargers.  I use an old GP fast charger that is good because it does 2300mAh AAs in about 70 minutes and charges each cell individually with -delta V and temperature monitoring of each cell to stop the charge and it works off of 12V DC so I can use it in the home and in the car (it came with a car DC lead and a mains cube).

Very slow chargers (24hr+) can actually be worse as they tend to be the least well designed cheap "trickle" chargers that never stop charging and cause metallic dendrites to grow in the cell. This causes partial short circuits in the cell and is one cause of the rapid self-discharge problem (even in NiCds that usually don't suffer from it).

Quote:

Originally Posted by AccordGuy 

 
 

Very slow chargers (24hr+) can actually be worse as they tend to be the least well designed cheap "trickle" chargers that never stop charging and cause metallic dendrites to grow in the cell. This causes partial short circuits in the cell and is one cause of the rapid self-discharge problem (even in NiCds that usually don't suffer from it).

Could this be why certain brands of "solar landscape lighting" have such terribly short life cycles?  I have some solar lights that I have used for years and they do pretty good.  A certain different brand, the batteries - and frankly the solar portion of the charger - last less than 1 year!  (had this problem with a certain brand on multiple product types...grrrrrr)

How the battery works and wha kind of rechargeable battery you need depends on what you are using it for. I learned this the hard way with my digital camera. Finally someone was nice enough to explain to me that my camera needed a certain type of battery. So now if I buy an electronic I alway read for the typed of battery power needed. This makes a huge difference.