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Rechargeable batteries


Pharisee
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I've just seen advertised some re-chargeable NiMH AA size batteries with a capacity of 1500mAh. They are about 0.5mm longer than the alkaline batteries I've been using (quoted dimensions 14.4 diameter, 50.7 long) but I guess that will be OK. The only thing I was unsure of was the voltage, they're only 1.2 volts per cell. Does anyone else use batteries of this type and does the 20% drop in voltage make a lot of difference to the operation of the GPSr ??

 

John

 

Age and treachery will always triumph over youth and ability.

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We use NiMh cells without any trouble.

 

Life is just a little shorter than alkaline (1600mAH) but much greater than NiCad.

 

We have 4 pairs of cells (one pair per GPS) and always take the spares with us just in case.

 

I suggest that if you have more than one pair, you mark them in some way and always use/charge them in their pairs which aparently prolongs the life of rechargeables.

 

I've been told that they don't like going totally flat so we change them before this happens.

 

One downside compared to NiCad is that they don't hold their charge for more that a few weeks, so we always recharge the day before we go caching. In reality, we have found that a week is not a problem.

 

Oh, we also still carry some emergency alkalines anyway.

 

Tim & June (Winchester)

 

See June, I told you that sign which said 'Unsuitable for Motor Vehicles' was wrong ! icon_smile.gif

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quote:
..........so we always recharge the day before we go caching. .........

 

Tim & June (Winchester)

 

See June, I told you that sign which said 'Unsuitable for Motor Vehicles' was wrong ! icon_smile.gif


 

You mean every night!!!! icon_wink.gif

 

http://www.trbf.com/teasel/view_cacherstats.php?cacherid=20434&go=Go%21

 

First Graph...... icon_biggrin.gif

 

dodgydaved

 

I'm NOT lost, I know exactly where I am, I'm here!

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We only use rechargeables. They're Uniross Ni-MH 1300mAh - 1.2v.I haven't noticed any difference between these and alkalines except the shorter life, the GPS works just as well. We always carry a couple of spare sets, but if they're fully charged, one set lasts pretty much all day.

 

Considering the cost savings on normal batteries, they're a 'must have'.

 

Incidentally, if you have a Wilkinsons store nearby, you can pick up a pack of 6 for £6.99.

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I use NiCads, which everyone else seems to find unsatisfactory. But my MLR takes 4 AA size, not two, which I suppose makes a big difference. The only slight problem is that the battery level indicator doesn't seem accurate with NiCads. With fresh batteries it shows full charge for a few minutes, then goes down to about a third and stays there until a few minutes before the batteries pack up.

 

Bill

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Its like this, folks...

 

The average Alkaline or other 'non-rechageable' type of cell (you all call them batteries, but actually they are only cells) has a quoted cell voltage of 1.5 volts. In practice, as soon as you start using them, the voltage starts to drop, (not much) gradually over the main period of use. At this rate, the 1.5V cell relatively quickly is down to about 1.2V and even lower as the cell starts to run out, so your equipment is geared to still work at these voltages. The graph so described is a gentle downward slope from the time you first switch on to the time the cell is dead. At some point, at about 1.0V the cell voltage drops of the edge of the cliff so to speak and the poor thing is then dead.

 

Nicad and NimH cells, by contrast, start of at 1.2V, but stay at 1.2V for 90% of their discharge cycle. The graph of this, if you can imagine, is practically flat. Then suddenly, at the end, the voltage plummets in a very short time, and the cell is dead and needs recharging.

 

What are the ramifications here? Well, your Etrex is designed to work at anything above about 1.1V per cell (ie about 2.2V). So a 1.5V Duracell is fine, but so is a 1.2V NimH or NiCad. The life you get out of one charge of the NimHs and Nicads is not as much as an alkaline but who cares? You just charge them up again. However, on bits of equipment that have battery indicators, those indicators are usually set up for standard cells (1.5V) so are designed to register a 1.2V cell as 'not full' which in the case of a Duracell is true. That is why they appear to lie about NimHs and Nicads. Don't worry. The deal with rechargeables is always to charge them fresh before you use them, then watch the time you have used them, because there is very little other indication that the cell is about to die. When it goes, it will just go, suddenly.

 

A few other points to consider when comparing the different options..

- Alkaline Cells have reliability and good durability on their side. They still work well when very cold.

- NiCads suffer from the dreaded "memory effect" which means that if you constantly only run it half down, then charge it up full then run it half down etc etc then after a while you will only be able to use that first half of its capacity. It will get to a stage where it thinks it is run out after only half the discharge.

- Nicads also have very high discharge currents available which is why they are used in model boats and suchlike where they have to run like the clappers for a few minutes. Duracells wouldn't stand it for a moment. Nicads can get very hot when run like this.

- Nicads lose their charge internally over a period of time. After about 4 weeks a fully charged Nicad is likely to be down to the last 30%

- Nicads don't like being very cold.

- NimH cells solve many of the problems of Nicads. They don't suffer from Memory effect nearly as badly. (they do suffer, but its not noticeable until you have run the half cycle for a lot lot longer...) They don't self-discharge as fast as NiCads, takes more like 8 weeks rather than 4 to get to 30%. Having said this, they can't deliver the instantaneous power that NiCads can, but can still manage more at one go than a duracell when pushed.

- Alakalines don't self discharge very much at all. They will store for years and still keep fresh.

- Both NimHs and Nicads are 1.2V whereas Alkaline and other non-rechargeables are 1.5V

 

NimH in case you are wondering stands for 'Nickel metal Hydride' and NiCd stands for 'Nickel-Cadmium' The fact that cadmium is now known to be a cumulative poison in the environment has meant that over recent years they are going more and more out of favour, since no-one is quite sure how to get rid of them when they finally do die.

 

icon_smile.gif

 

No trees were harmed during the production of this posting, but a large number of electrons were terribly inconvenienced....

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quote:
Originally posted by MCL:

Its like this, folks...

 

The average Alkaline.............

.............they finally do die.

 


 

So... the general consensus is that 1.2 volts per cell is OK and the slightly shorter working life per charge is also acceptable.

 

Great... thanks a lot, peoples. I'll go and buy some.

 

John

 

Age and treachery will always triumph over youth and ability.

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I have used both Nicad and NiMH batteries without problems, if you own a Garmin GPS a number of them allow you to specify the type of battery in the system setup, so if you use rechargeables, the battery meter remains accurate.

The cheapest place I have found for batteries is www.7dayshop.com , they are currently doing 2000maH batteries at abour £6 for a pack of 4

 

Best Wishes

 

Mark

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quote:
Originally posted by conedxf & family:

I have used both Nicad and NiMH batteries without problems, if you own a Garmin GPS a number of them allow you to specify the type of battery in the system setup, so if you use rechargeables, the battery meter remains accurate.

The cheapest place I have found for batteries is http://www.7dayshop.com , they are currently doing 2000maH batteries at abour £6 for a pack of 4

 

Best Wishes

 

Mark


 

Don't forget that, as Team Blitz reported on 30/01, Maplin have packs of 12 NiMH 1800mAh rechargeables on offer at the moment for the bargain price of £14.99... I bought 2 packs, and am pleased with them so far...

 

G.

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quote:
Originally posted by MCL:

 

- Alkaline Cells have reliability and good durability on their side. They still work well when very cold.


 

Not Kodak ones. I was skiing last week and the temperature could be as cold as -10 C or colder. The alkaline batteries I was using could go apparently dead after about four hours. I once had the bizarre experience of holding the GPS in a bubble lift and watching the battery meter go *up* as the batteries warmed up in my hand.

 

-------

jeremyp

The second ten million caches were the worst too.

http://www.jeremyp.net/geocaching

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quote:
Originally posted by jeremyp:

The alkaline batteries I was using could go apparently dead after about four hours. I once had the bizarre experience of holding the GPS in a bubble lift and watching the battery meter go *up* as the batteries warmed up in my hand.


 

Ah yes, not *that* cold. There are very few cells/batteries that work *well* at those kind of temperatures. when I said very cold I meant down to and just below freezing, say about -2 or -3. Crikey, even lead-acid ones (as in cars) have trouble down there, witness the sluggish turnover on very cold mornings after a hard frost... Car batteries have a liquid content which is far better at presenting a good electrical interface with the cell poles than dry cells which have a gell/powder content.

 

If you want electrical power at temperatures much lower than that, you should think about using a fuel cell, like they do in space. They cost a few thousand quid, but they do work down to about 10 degrees above absolute zero, so I am told...

 

The Maplin offer on NimHs is now finished, I was told in the milton Keynes Maplin store today. They are doing cheap alkalines though. 8 AAs for £2.99. They are Varta ones, not Duracell. ND08 is the code, but only until the end of this week I was told.

 

I was thinking of cheap cache-fillers...

 

No trees were harmed during the production of this posting, but a large number of electrons were terribly inconvenienced....

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quote:
Originally posted by jeremyp:

I once had the bizarre experience of holding the GPS in a bubble lift...


 

Yes that would be a pretty bizarre experience I imagine.

 

What do they need a thing like that for just to lift bubbles anyway? They're not made out of heavy water or something like that are they?

 

No trees were harmed during the production of this posting, but a large number of electrons were terribly inconvenienced....

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quote:
Originally posted by MCL:

 

What do they need a thing like that for just to lift bubbles anyway? They're not made out of heavy water or something like that are they?


 

It's a ski lift a bit like a chair lift, but the passengers are completely enclosed in a fibreglass shell or "bubble".

 

-------

jeremyp

The second ten million caches were the worst too.

http://www.jeremyp.net/geocaching

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Most people just throw them away, despite the environmentalists pleas. However, a lot of local council waste tips have a bin for collecting odd and dodgy stuff like chemicals and nasty oils. Talk to the staff at your local one and ask them which bin they want you to stick them in. Thats what I do here in Milton Keynes.

 

No trees were harmed during the production of this posting, but a large number of electrons were terribly inconvenienced....

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quote:
Originally posted by jstead:

7dayshop are also offering 4 Uniross 2000 mAh batteries with a Uniross quick charger for use in car or on mains at £17.99. I've just ordered one.


 

Argh! We recently bought one of these... won't say what we paid icon_frown.gif Anyway... we're very happy... they've been out on a couple of caches with us, and charged perfectly fine while driving icon_smile.gif

 

Nice bit of kit.

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quote:
Originally posted by Stu & Sarah:

quote:
Originally posted by jstead:

7dayshop are also offering 4 Uniross 2000 mAh batteries with a Uniross quick charger for use in car or on mains at £17.99. I've just ordered one.


 

Argh! We recently bought one of these... won't say what we paid icon_frown.gif Anyway... we're very happy... they've been out on a couple of caches with us, and charged perfectly fine while driving icon_smile.gif

 

Nice bit of kit.


 

I've just taken delivery (took 6 days) of one of these Uniross chargers from this company. It's not much bigger than a fag packet, appears fine and charges quickly. Also bought 4 2000mAH NiMi too (£5.75). They're also doing Panasonic 2000mAH for £5.95.

 

7dayshop.com are doing a special offer where delivery is free for internet orders made before 5pm Monday 24th Feb.

 

I've no connection with this company other than being happy with their service.

 

motley. adj. varied in appearance or character.

crew. n. group of people.

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quote:
Originally posted by Motley Crew:

quote:
Originally posted by Stu & Sarah:
Originally posted by jstead:

7dayshop are also offering 4 Uniross 2000 mAh batteries with a Uniross quick charger for use in car or on mains at £17.99. I've just ordered one.


 

Argh! We recently bought one of these... won't say what we paid icon_frown.gif


 

If you check the next page on from the Uniross charger, there's one by Hama which looks to be the same spec (fast charger, 3 pin UK plug and adaptor for use in car, four 2000mHh batteries etc, etc) but slightly cheaper still!

 

I've just ordered one, plus an additional four 2000mAh batteries and am awaiting delivery.

 

BTW - there's a note on the Uniross advert saying that the information that there were 8 batteries with that unit was an error.

 

--... ...--

Morseman

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I've just ordered one of the Hama ones - now I just need to get my cigar lighter socket in the car working!

 

7dayshop also do 5-packs of 24 exp disposible cameras for £9.50 - great for if you're placing lots of caches this Easter!

 

Lizzzzzzzzzzzzzzeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

 

Don't you think that sooner or later someone will notice that its a mobile phone not a GPS your using???

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The Hama one was not available when I ordered mine.

 

I've been impressed so far with the charger and the 2000mAH batteries, so much so that I've purchased a further 8 making a total of 16. The charger will make a great hand warmer in the winter months too! icon_wink.gif Of these 16 batteries 8 are installed in my 'devices' and I carry 8 spares in one of 7 day shops snazzy AA battery holders.

 

The 2000mAH batts last much longer than Duracells in my (cheapo) Packard Bell digital camera - this thing devours batteries at an alarming rate. The duracells clap out after just a few flash pictures whereas the 2000's are able to be used for numerous flash piccies.

 

Overall I'm well pleased with this stuff.

 

motley. adj. varied in appearance or character.

crew. n. group of people.

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quote:
Originally posted by sky high boys:

Iwas under the impression that the higher the mAh the better.

the best i've found is duracell rechargeable 1.2v ,1800 mAh.

got these in schipol airport duty free!!!

can't find anything as powerfull in uk .

would like to know


 

The higher the mAh rating, the longer the battery should run a particular piece of equipment. However, normally you pay more for higher capacity batteries.

 

For equipment like digital cameras, which use quite a lot of power, the higher the capacity (in mAh) the longer it can be used before you need to replace the batteries.

 

If you use rechargeables, this can save on the costs of keep buying batteries.

 

I have eight 2000mAh batteries, my camera uses four and I keep four ready to swap over to whilst I recharge the ones that are discharged.

 

I bought them from 7dayshop.com but I have seen 2000mAh batteries in places like Maplins, who have shops in many of the large UK cities (Sheffield has two!) and also supply by mail order.

 

I'm not supporting either company over the other, I use both at times, but 7dayshop was cheaper than Maplins for the charger and extra batteries which is why I bought mine from them.

 

--... ...--

Morseman

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