rechargeable AA batteries any good?

colhel

colhel

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I use a lot of AA and AAA batteries on board for led lights, GPS and torches etc. At present I'm using alkaline batteries. I saw some rechargeables in Tesco's just now for about a tenner, for this you get 4 batteries and a mains charger. The make was well known, but easily forgotten, because I forgot it.
Are these any good? How long do the batteries last before they need replacing? How long do they hold their charge for? Anyone know?

Cheers

Col
 
7dayshop.com or battery-force.co.uk are very cheap for all types of battery. the larger capacity rechargable (2700mah) are good and last a long time. If using Ni-cad be shaw to fully charge and discharge them or they lose capacity.
 
They vary, have a look at the mAh rating, e.g. AA NiMH batts with 2500 mAH rating should do pretty well for most things you might use them for...
 
I've used a lot at home - mostly I find them very good. Check the mAH rating and go for something like 2500-2700mAH - those are roughly compatible with standard alkaline batteries, These days I would avoid NiCads - too low capacity and too tricky to recharge.

They do self discharge - so over a period of a few months they will gradually lose their charge.

They are not suitable for all equipment as they are actually only about 1.2V - my handheld radio would not work with them even when they were fully charged, and any device that tries to monitor or report battery state will also get it badly wrong.
 
I have been using 24590mAh AA and 1000mAh AAA Duracell's bought from Amazon and using a Duracell charger. These have been very reliable over the past 3 years and I have just received another 4 AA's and 8 AAA's which I am charging prior to use. Digital camera, torches, wireless mice the list goes on and on.
 
Very good but.......

Hi.

I use rechargeable AA batteries. The thing to bear in mind with them is that they run at a slightly lower voltage so if voltage is critical dont use them. Also they do not give much warning when discharged unlike conventional batteries. They just peg out in a matter of minutes. Keep spares handy.

Regards.

Alan.
 
As described above, the two potential problems are the fact that the full charge voltage is less than the 1.5V of a regular battery and the self-discharge.

I haven't found many things that will not work with a fully charged set of NiMH cells. The bigger disadvantage is when you use them in things like remote controls that don't draw much current and are only used intermittently - they run flat sooner than ordinary batteries of the same capacity would because they self-discharge over a period of a couple of months.
 
Rechargeable batteries have always been something of a disappointment to me. ( at least Nicads and NiMH)

OK perhaps for items in frequent use but they don't seem hold their charge for all that long so next to useless for items that are used infrequently such as torches. My experience is that they are usually flat when you come to use a torch

I do have a set in my camera but despite having bought them with a fancy charger I find them difficult to recharge. I always carry a set of alkaline batteries.

Alkaline batteries have a very long shelf life so I'd recommend them for equipment only used occasionally.

Only use rechargeable in items that would otherwise get through large numbers of alkalines.
 
NiCd and NiMH rechargeable batteries self-discharge over time, and therefore are only really suitable to applications where they will be used frequently. However, the new generation of "hybrid" NiMH batteries are much better and have very low rates of self discharge. The best (but of course the most expensive) are Sanyo Eneloops which are excellent - I have been using them for over a year, and they have performed well. A cheaper alternative is the Vapextech green cells. If you search on ebay, you'll find them - £5.85 for four, post free. No connection to seller, and I willingly pay more for the Eneloops.
 
I've had a few over several years I was getting problems with some of them after a while, they just would last long after a full charge. I bought a new charger that shows the state of each battery and also if the battery is knackered after a full charge, several of the ones I had been using showed up as faulty so chucked them out and bought new ones. If I hadn't bought the new charger I would have been none the wiser. When they are good the 2500 and 2700mah last longer thannormal AAs.
 
Uniross Hybrio batteries are also very good. They hold useable charge for over a year without self discharging. I now use them a lot. Like the Eneloops, they recharge in standard NiMH chargers.
 
I also use eneloop from 7dayshop.com, and have been very impressed as they hold charge longer and are much more effective with my camera than normal re-chargable. I get as many pictures as aset of duracell. The Uniross sound equally good.
I have found the 7dayshop Battery Charger - 808LCD - Super Fast - AA / AAA excellent and use that to charge batteries for radio controlled sailing boats with use a lot of juice. I'm guessing lots of chargers work well, but so far this is the best I've used.

http://www.7dayshop.com/catalog/product_info.php?cPath=777_3&products_id=105029

And I have no connection to 7day.. just found them cheaper than others and reasonable service.
 
I don't claim to be an expert, but it seems that technology in this area moves fast. I had little truck with Nicads and NiMH except in applications giving them regular exercise. The lastes rechargeables I have been getting from Maplin titled "Hybrid" and I believe the "Eneloop" claim all the benefits of rechargeables with the ability to sustain charge of "once-only" alkalines. They indeed do pretty well in my hands (clocks for six months and the like). I run all the dry cell equipment on the boat off them: handheld VHF and GPS, clock, torches etc. They do deliver a lower voltage than alkalines, and I'm not quite sure that they quite live up to the claims about sustaining charge - but they are the best rechargeables in my opinion. I would not get distracted by claimed maximum capacity. If you are anything like me they are more likely to die by accidentally being left around uncharged or in an unused device than to fail you due to lack of capacity. Robustness against abuse is what I need.
 
Many of the problems reported with rechargeables arise because most of the cheaper chargers do not do the job properly. Rather than monitor the actual state of charge, they simply apply a current for a set time. If the battery is still part charged, then they get overcharged which can damage them, while if they are fully discharged, they are not kept on charge for long enough so never reach full capacity. This also can damage them - particualrly the cheaper types.

If you are going to use them regaularly it is well worth buying a proper charger which gives you control over the charging rate, and senses the battery voltage to ensure it is fully charged.

One of the cheap plug in chargers I have now thrown away only took a discharged battery up to around 75% before switching off.

Since investing in a proper 'smart' charger, I find batteries holding a higher charge for noticeably longer. In my DSLR camera for example four 2500ma AA will now allow over 500 frames, whereas previously I was lucky to get 350 - 400 from the same set. Using cheap chargers I would sometimes find them failing after less than 300 frames.

My Techno Line BL700 charger cost just under £40 from Amazon. It charges each battery individually, will give me an exact reading of the state of charge of each individual battery, can measure the actual capacity of each battery so that I know when one is beginning to fail, and has a restore function which works a battery through several full charge discharge cycles at optimum levels which extends the service life of an older battery very considerably (Several batteries which showed up as reduced capacity have been restored and are now working properly again, so it is well on the way to paying for itself! Its not the easiest to use, and needs a little perseverance to get the best out of it - but its well worth it.
 
I have several rechargeable AA setups; the best by a long chalk are the blue 'AA2700' batteries & charger from Jessops, the camera shop.

The red Uniross jobs from hardware shops don't even take a charge now, and have only seen light to moderate use for about 3 years.

Then again I went into my local Jessops last week intending to buy more 2700 batteries & another charger but there were none in sight; haven't got round to finding if they or similar are still available.
 
the_wanderer said:
I use rechargeable AA batteries. The thing to bear in mind with them is that they run at a slightly lower voltage so if voltage is critical dont use them. Also they do not give much warning when discharged unlike conventional batteries. They just peg out in a matter of minutes...
Click to expand...

And they self discharge rapidly.

For all these reasons they are useless for torches IMO.
 
Rechargeable batteries

Nicad and NiMh have a voltage which as said is close to 1.2 volts per cell. This voltage stays very close to constant from fully charged till it rapidly drops to zero at end of discharge. hence I am very sceptical of chargers which monitor voltage and so called fuel gauge battery level indicators.
(some devices because of this constant voltage use a current in current out counter to give battery state. much better)
Non rechargeable 1.5 volt batteries by contrast decline in voltage pretty much in a linear manner from 1.5 volts to about 1 volt when they are dead. Hence a volt meter can easily measure condition.
With NiMh with this constant voltage I am again very sceptical of chargers that it is claimed will cut off charge when full. I would prefer a low current constant current charger which will recharge over several days. This w9ill ensure full charge but the current is so low as to not harm the battery by overcharging.
Certainly fast chargers are really asking for trouble. (IMHO)
The battery condition meters and smart chargers are a result of demand by consumers for something which can not be achieved it is provided because it is wanted not because it works. (I may be wrong of course)
I have however used wet Nicad batteries as the ships batteries for 30 years with great success. (and long life) good luck olewill
 
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