FOAK: Paging the Non-Recharable, chargable AA batteryisti

Greetings,

I now have occasion to buy shitloads of Alkaline AA Duracell type
batteries and it's costing a small bleedin' fortune. I could just go out
and buy a battery charger and a load of Ni-MH but these, although
cheaper in the long run, only put out 1.2v which is a bit shit when your
appliance takes twelve(!) of the fuckers. Now, I know there's chargers
out there now that claim to recharge non-rechargeable batteries but
which ones are best an which ones charge to 1.5v or as close as possible
and how long do they last once charged? I know you can only recharge
then 10 times or so but I don't mind that if the voltage and amperage is
ok. I've Googled which is ok but not having used anything like this
before it's not easy to tell truth from marketing hype and bollocks.

Anyone?

 

The fact that NiMH batteries only put out 1.2V shouldn't make a
difference in most applications. They'll put out close to 1.2V whether
they're under load or not, and maintain this as they're depleted, as
they have a very low internal resistance.

Alkaline batteries will show ~1.5V when tested without a load, but their
higher internal resistance will mean that in use their output is likely
to be significantly less.

Also, decent rechargeables are likely to have a higher capacity than any
but the most expensive non-rechargeables, and be able to deliver a
higher current.

In short: unless you're trying to use something that's particularly
voltage-sensitive, you'll be better off using decent rechargeables.

 

I've used one of these, from the "Innovations" cataloge, for many
years now, with some success. They tend to be called "reconditioners"
rather than chargers, and they certainly don't "recharge" like you
might want.

But wht they do is make batteries more or less re-useable, depending
on drainage patterns, age and god-knows-what else. Typically, a
low-drain AA battery in more-or-less constant use for several months
will regain up to 80% of its original capacity on first recharge, then
perhaps 70, 60 and down. Sometimes they just won't recharge at all,
sometimes they only get a very small amount of their original capacity
back.

There's a display for each cell that tells you all this, so you can
see how good a recharged one's going to be and whgen to throw it away.

10 time might be optimistic - certainly two or three is normal but
beyond that a high proportion either won't charge or will only get a
very low capacity. Voltage is fine. 'Amperage' I dunno what you mean,
but they've always seemed to perform just as well as the originals,
barring their state of charge.


IME they're about as good for re-usability as many older NiCads were,
with generally longer charge-life, but since decent-capacity NiMh ones
have become available and affordable I really CBA any more, too much
hassle trying to work out which ones are any good, leaving them on too
long (they take _hours_ to charge) and boiling them, etc. etc. etc.

--
_______
..'_/_|_\_'. Ace (b.rogers at ifrance.com)
\`\ | /`/
`\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2, IBB#10
`\|/`
`

 

The latest rash of 2700mAh batts look just the ticket. What you say
about 1.2v V 1.5v under and not under load is interesting. Ideally what
I want is full capacity for as long as possible without the batteries
suddenly crashing, *some* warning would be good.

I'll be using them for R/C radios and receivers and obviously I don't
want the receiver battery suddenly going kaputski when my car's doing
50mph+ in the wrong direction[1] and now way to run fast enough to stop
catastrophic damage[2] but don't want them to run out so slowly that
they become unresponsive way before they're actually dead, iyswim.

[1] I have a failsafe but this only works if the signal is
lost/interrupted/interfered with from the transmitter.

[2] Has happened recently. Wrote the front of the car off.

 

Right, that's it then. I don't want to re-use alkalines, etc. Proper
rechargable are in order.

Thnaks

 

I raced at National level and was Head Referee for the BRCA 1/10th
off-road National Championships for many years ... _Everyone_ including
the World Champion, uses rechargeables. Simply not worth using
Alkalines, proper rechargeables (decent ones) are absolutely what you
need, and a good charger.

Mind, we only run five minute races ... but my Transmitter (KO Vantage
Tye R) has had the same batteries in it for a year with only two
recharges.

If you're also using them for the receiver, (Nitro cars mostly) then
their life-span _should_ be about the same or better, for various
values of ...

If (when) you get anal about it, keep a log of times of battery use to
get a pattern so you know to a level; of uncertainty, how long you
should have left in your cellpacks.

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi 'Big and Butch'
Dyna Tech Cro-Mo comp "When I feel fit enough'
ebay stuff 140263469749

 

Given your intended use, I can't imagine what sort of warning you'd be
likely to get.

Also, NiMH batteries are much more tolerant of repeated partial
discharge/charge cycles than were older rechargeables, without the
memory effects and loss of effective capacity. IIRC, the recommendation
is to cycle them completely (i.e. full charge, full discharge) the first
few times, after that you should be able to sling them in the charger
whenever you feel like it (e.g. after every use).

 

I was in Sainbury's yesterday and saw a Duracell fast (1 hour) charger
with four 2300mAh batteries. I don't suppose there's much difference
between these and the 2700mAh pack that were next to it (but no
charger). Not bad at 6 quid a pack either, I thought.

Same as that. I just got an Acoms thing secondhand with some cheap
non-brand batteries in and I've not needed to replace them yet. Been
using them for a few hours, too.

Well, (and yes, I'm using a .21 Force nitro) I've had to change brand
new good quality alkaline batteries twice and still have the cheapo ones
in the radio so I'm not sure how you came by that ;-)

Who needs to get anal, that's all just part of the fun ;-)

 

Right, so I need a charger/discharger then because putting them in a
clock when I've finished with them will take years! ;-)

I'd want t cycle them every now and again anyway, that's just something
else to look out for (the discharger bit)

 

Stuff 'em in a torch, or a digital camera with a discharge facility. Or
you could be really pikey and improvise something with some tape, a
piece of wire, and an appropriately-rated bulb.

 

Good idea.

The torch idea was better and as I have one that takes AAs, I'll use that.

Muchas grassy-arse

 

The dry cell batteries I used to look after for Danny's RGV race bike
were discharged by plugging them into a 55W halogen headlight bulb in
the workshop, and at the circuit I discharged them by plugging them
into the van's nearside headlight. All I had to do was make a patch
lead with a 3-pin headlight connector block one end and a battery
connector on the other.

 

Dunno either ... Thinking further, and somewhat aloud, there's
normally eight cells in the tranny and four in the reciever, and the
receiver packs do take more battery drain as they're also powering the
servos on a Nitro. I'd guess that as we raced we took note, mentally
mostly, of how long we run cellpacks and changed them either when one
set died or when we thought they were about to die, so my statement
that they lasted just as long is probably wrong, it's just that we
would tend to replace/charge them at the same time ... which, being
rechargeable, isn't much of a problem. I had something like four
receiver cellpacks back when I raced Nitro ...


I'd guess that a properly charged set of receiver cells for a Nitro
should last a racer a full day ... which can be maybe two hours of
full-on racing over the day, and that most packs nowadays can last all
weekend including extra 'testing' overnight, so up to about 6 hours a
cellpack.

Indeed, 8th scale Nitro racing can have 20 minute heats and 45 minute
finals, so cell packs need to last a lot longer than this for safety.

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi 'Big and Butch'
Dyna Tech Cro-Mo comp "When I feel fit enough'
ebay stuff 140263469749

 

What Paul said and once you have some decent cells in place you need
to get to know what constitutes a safe run time.

From a voltage pov you can replace (say) 4 x 1.5V Alkaline's with 5 x
1.2V NiMH. Any decent model shop will sell you tagged (to allow you to
make up your own packs) or untagged *quality* cells (Sanyo etc, often
a very different beast to what you will buy from Argos etc).

When I was racing 10th scale cars that used receiver batteries I would
know a battery pack would last a whole race day, but as Paul mentioned
that was a pretty predictable run time (n x 5 min heats, semi's, final
etc). When racing the RC Lasers (RC sailing boats) we can be on the
water for nearly the whole day so the TX and RX batteries would have
to last the day, or you would carry a duplicate set or rapid charger
(for a top up during the breaks etc).

I used to charge all the batteries overnight with an occasional full
discharge / recharge to keep the cells active.

Ouch. [1] :-(

All the best ..

T i m

[1] An RC yacht generally just goes round in circles in that instance.
;-)

 

In the situation I use them in I either use 9 Alkaline AA or 10 Ni-MH to
give me the 12 volts.

I remade the battery case to take either. I slip in a dummy AA with a
strait through connection for the Alkaline AA if I ever need them.