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Rechargeable Batteries

dUnKle

Distinguished Member
Over the last year or so I have made the move towards rechargeable batteries and have a couple of dozen Eneloop and Amazon own brand AA

Now they dont get used that much, to be fair they seem to last for ages, however I have a DAB radio which I use in shed / garage / garden when working and this lasts around 24 hours or so on a set of 4 AA before needing a charge

My issue is that more often than not, when going to charge a battery, 1 always displays as NULL on the charger 7dayshop AA and AAA Intelligent NiMH Professional DS-SC1000 SUPER FAST Battery Charger Multi Mode LCD Display this > 7dayshop AA and AAA Intelligent NiMH Professional DS-SC1000 SUPER FAST Battery Charger Multi Mode LCD Display )

Now I understand that batteries have a finite lifespan, but would estimate none of them have been through the charger more than a handful of times, with some of them even doing it on first charge

Am I just unlucky ?
 

nheather

Distinguished Member
It might be the voltage rather than the charge.

Normal cells are 1.5v (so 6.0v for 4 cells) whereas rechargeable are 1.2v (so 4.8v for 4 cells).

Fresh cells normally have a higher voltage which drops down to nominal fairly quickly.

Now many devices are designed with rechargeable batteries in mind so operate fine at the lower voltage.

What you might be seeing is that the fresh recharged voltage is just high enough to make the radio circuitry work but after a short while as the voltage begins to drop off it is not enough.

So it is not that the batteries are flat, just that the voltage is not sufficient.

Might not be this but could be.

Cheers,

Nigel
 

dUnKle

Distinguished Member
Ok,
So is there a way of getting them to start charging again now the charger is showing them as Null ?
 

EndlessWaves

Distinguished Member
Ok,
So is there a way of getting them to start charging again now the charger is showing them as Null ?

I believe he was talking about the short battery life in the radio rather than the null issue. Or possibly assuming that the null display meant that they were still too high a voltage (i.e. too much charge) for the charger to start recharging them.

That charger has discharge and test modes too (the manual is under the additional tab in the link). Does either of those, or any of the other functions like voltage display, work or do they show null whatever you do?

Unfortunately the manual doesn't give the conditions under which it will give a null display.

Where are you buying the batteries from? There are lots of fake batteries on ebay/amazon marketplace. Although if the Amazon own brand ones are suffering from this then it's unlikely to be that.

Eneloops do have a reputation for a very high level of quality control so I'd be surprised if it was bad luck.

You can damage batteries by drawing too much current from them, but usually AAs are good for at least half an amp and 24 hours from them is far less than that.

It might be worth sticking to disposables for the radio and see if the issue goes away if you suspect that's the device killing them.
 

sep8001

Prominent Member
When I normally get a null on the same charger as yours, I put that set of batteries to charge in my eneloop slow charger.

This sorts them out, I think the reason you get null is that that cell is completely drained.
 

dUnKle

Distinguished Member
Cheers. Never knew about the extra functions of the charger. Will try that and also a slow charger

I was actually quite impressed with the 24 hours or so that the batteries last in the dab radio. The expensive disposables I had previously only lasted about half that so am impressed with how powerful the rechargeable are.

All of them have been from Amazon

I'll try the charger functions and if no joy get a slow charger.
 

jenam93

Prominent Member
DAB radios are pretty notorious for chewing through batteries.

When I get a null rechargeable, I tend to put it in a cheap charger to give it a zap, then condition it in the Technoline charger I have (which is what says it is null to start with)
 

dUnKle

Distinguished Member
DAB radios are pretty notorious for chewing through batteries.

When I get a null rechargeable, I tend to put it in a cheap charger to give it a zap, then condition it in the Technoline charger I have (which is what says it is null to start with)

Any suggestions on a cheap one
 

atothej

Established Member
I had similar problems with batteries a few years ago, and actually threw a load out if they were showing as NULL on the charger. A few went, including eneloops, duracell and 7-shop branded ones.

I saw on a few website since that you can get them back to life. Get a fully charge battery of the same size, and connect with the null battery with a bit of wire (I use a paperclip) - pos to pos, neg to neg. Hold them inplace for 10-20 seconds, and enough charge should transfer for the Null battery to be recognised by the charger again.

As you can tell, I'm not very clued up with voltage/wattage/Mah etc etc so am unable to go into the technical aspect of it, but this has worked many times for me since.
 

dUnKle

Distinguished Member
I had similar problems with batteries a few years ago, and actually threw a load out if they were showing as NULL on the charger. A few went, including eneloops, duracell and 7-shop branded ones.

I saw on a few website since that you can get them back to life. Get a fully charge battery of the same size, and connect with the null battery with a bit of wire (I use a paperclip) - pos to pos, neg to neg. Hold them inplace for 10-20 seconds, and enough charge should transfer for the Null battery to be recognised by the charger again.

As you can tell, I'm not very clued up with voltage/wattage/Mah etc etc so am unable to go into the technical aspect of it, but this has worked many times for me since.

I shall try that as that sounds just like me and my situation

curiously enough, if I put the Null battery back inss - however if i replace
 

EndlessWaves

Distinguished Member
That sort of tomfoolery with stupid chargers or paperclips is best used in moderation. AA batteries are fairly safe so you can usually get away with it, but don't get into the habit of doing it and don't use it on batteries you suspect are worn out or higher powered batteries (e.g. Lithium-ion 18650).
 
D

Deleted member 27989

Guest
As said earlier in this thread a "dumb" charger may get it going again. The risk is "what if it is truly faulty". The safety on smart chargers is there for a reason.

I use a Maha C9000 charger, if I encounter something like that I'll use the discharge mode which effectively causes this on purpose to then slowly build it up again. Followed by a refresh cycle. Excellent bit of kit :)
 

blue max

Distinguished Member
I have that one - well, the TechnoLine BC700. And it does exactly the same as you describe. I just use a bog standard one to give it a kick, then it seems to be recognised. If that doesn't work, chances are the cell is trash.
 

dUnKle

Distinguished Member
Well I never got round to replacing / adding a dumb charger
Can anyone suggest a good value for money one
At least one in 4 of my batteries, mostly eneloops with amazon basic as well, always shows as null now

Be it one from an Xbox controller, the dab radio or one of daughters toys
I still resort to the trick above to having to get the null battery to charge

Don’t want anything special or fast. I always leave the 7 day shop one in default as never in hurry get battery charged

This appears to be what I’m using

https://www.amazon.co.uk/Youshiko-Y...coding=UTF8&psc=1&refRID=5ATYYGDT55C2HA6WG7QN

Although mine is 7 day shop branded
 

Sonic67

Banned
Any suggestions on a cheap one
Buy cheap, buy twice.

No idea on what you are buying but some batteries can hold up power for a while, others lose it rapidly. I use a pure radio with the rechargeable battery pack. It's lasted for years and rarely gets recharged.
 

Kailash

Prominent Member
** going to resurrect this one :hiya:

i haven't bought rechargeable batteries in a long time but grabbed some eneloop pro AAs recently, 2500mAh.
do you need a special charger for these? i used my old Energiser charger with them and they seem ok, but want to make sure i'm getting the most from them.

also what is it with these pre-charged rechargeables. there is actually a setting in my device (Garmin) to select AA battery type NiMH or Precharged NiMH, which i assume is for my eneloops.
 

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