Does anyone publish "What Rechargable Battery" magazine ?

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Nick2

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Does anyone publish \"What Rechargable Battery\" magazine ?

As I find more and more boat stuff and kids toys rely upon battery power I wondered whether there is anything in particular that I should look for in a rechargable set of assorted batteries.

I am really looking for top of the range stuff and I can't get much sense from the Maplin bods...so any help appreciated.

Nick

<hr width=100% size=1><A target="_blank" HREF=http://arweb.co.uk/argallery/Nick2>http://arweb.co.uk/argallery/Nick2</A>
 
Re: Does anyone publish \"What Rechargable Battery\" magazine ?

Read a very interesting paper by a guy who designs power systems for space craft in one of the big name US aerospace companies. Was about two years ago so may be some change now, and mainly covered NiCd and NiMH. Two gems, which certainly matches my experience with them were:

The memory effect of NiCds is basically a myth. Early on it was discovered that cycling them under certain conditions (constantly to the same point of discharge, 20% if I recall) caused a memory effect. Even if that existed in current batteries it would not be replicated in normal use. The advice to discharge NiCds to depletion to avoid memory effect actually runs the risk of running cells in a pack into reverse voltage and damaging them.

NiMH batteries hold more charge per unit weight than NiCds, but the number of lifetime charge discharge cycles for NiMH batteries is less than for NiCds. Over battery's useful lifetime both deliver a similar amount of charge - the NiCds (weight for weight) just have to be charged more frequently, and the NiMH cost more. NiMH was only important if battery weight/size and single charge capacity was an issue (cellphones, notebook computers, etc)

I always buy name brands, not store labelled rechargables, and usually NiCds as they are (certainly here) much cheaper over the lifetime of the battery.

While I never worry about memory effect and use quite a number of NiCds in various duties including constant trickle charge and partial cycling I have never experienced memory effect. However, all batteries have a finite life in number of charge cycles, so they do die eventually.

John

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Re: Does anyone publish \"What Rechargable Battery\" magazine ?

I have used a lot of NiCads at work over the past 20 years, and have read the paper and others that you state. However in practice I do find that there is a memory effect of some type and that repeated deep charging and discharging will prolong the life of a battery. One danger of leavong batteries in a fully discharged state is that the weakest cell reverse charges and dies, so leave your batteries in a charged state and recharge occasionally.

Despite the figures, I don't find that NIMH batteries have a shorter lifespan- perhaps because most NiCad bateries have been binned after 500 cycles due to the so caled memory effect!

We'are now moving over to Lithium ion batteries which are far better but cannot deliver high currents.

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Re: Does anyone publish \"What Rechargable Battery\" magazine ?

Forgot to say than NiCad batteries are being phased out in preference for NIMH due to environmental concerns about dumping cadmium

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Re: Does anyone publish \"What Rechargable Battery\" magazine ?

I second 7 day shop

very good service so far, their battery cases are brilliant for storing cells, only about 3 squid each too.

Their digi memory is expensive though!

<hr width=100% size=1>Julian

<A target="_blank" HREF=http://www.topcatsail.co.uk>Top Cat Homepage</A>
 
Re: Does anyone publish "What Rechargable Battery" magazine ?

According to my wife this must be one of the 'sadest' posts ever. She was also surprised that I hadn't responded sooner with some sad words /forums/images/icons/wink.gif

Having children similar in age to yours we are converted by the use of NiMh cells. The AA size 2.0 mAh ones give a good life (two days or more days in a Gameboy) and are a reasonable cost. Now have two of the combined mains / 12V quick chargers available from <A target="_blank" HREF=http://www.7dayshop.com/> 7dayshop </A> together with about 20 NiCad and NiMh cells that just about keeps all of us going with toys, torches, gameboys, digi cameras, GPS etc etc.

After quite a bit of experience with electric powered models, you can get really sohpisticated chargers that are not really necessary unless you want ultimate performance. Modern cell technology, both NiMh and NiCad is so good that memory affect is really a thing of the past and although a stated life of 500 charges is typical, we get more than this although at a reducing performance.



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Re: Does anyone publish \"What Rechargable Battery\" magazine ?

7 day shop are just down the road from me


<hr width=100% size=1>Dom

<A target="_blank" HREF=http://www.soltron.co.uk>the website</A>
 
Re: Does anyone publish "What Rechargable Battery" magazine ?

Before I retired I used to teach Deaf Children and daily used individual radio links with each child. These were fitted every morning as the kids arrived in the school and were on all day. At the end of school the units were placed in a charger overnight for the following day. Batteries were supposed to last a year but my experience showed that they lasted some two terms only although they were of use afterwards as a spare if anything untoward happened.
I also had a hand held rechargeable radio and found that whenever I wanted to use it the cells were flat.
Now anything that is on my boat that is not on the fixed 12 volt circuit (hand held radio, spare sat nav etc in my grab bag) are all powered by alkaline cells and there are plenty of spares carried to use as necessary. I'm afraid I just do not trust rechargeable cells when at sea!

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Re: Does anyone publish \"What Rechargable Battery\"

Is that another local one?

Happy New Year Steve, coming to the 3M evening in Feb?

<hr width=100% size=1>Dom

<A target="_blank" HREF=http://www.soltron.co.uk>the website</A>
 
Re: Does anyone publish \"What Rechargable Battery\" magazine ?

Depends entirely on the type of rechargeable.

My handlheld has Lithium Ion (Li-ion) rechargeable. It never drains while not in use, and everytime you turn it on, it's lost no charge, even over months. It also powers the thing for ages. I left it on once for 2 weeks to see if I could drain it (yes eventually, and it was being use for transmission in normal use as well)

I trust it entirely.

<hr width=100% size=1> I asked an economist for her phone number....and she gave me an estimate
 
Re: Does anyone publish "What Rechargable Battery" magazine ?

I agree (yet again!) on that.

With respect to batteries other than Li-ion I cannot comment from experience on drain of NiMH as all mine are in things which are constantly cycled so never have a chance to drain "not in use".

However, I have never had a problem with NiCd's draining while not in use. NiCds have the characteristic of holding their voltage up right to the last moments of their charge, at which point the voltage very rapidly collapses. While this is a very useful characteristic (but remembering if using them instead of non rechargables they are only 1.25v) I think it also gives some the impression that they are unreliable and self drain more than they actually do. It is easy to put the powered device away after use with the batteries seeming to be highly charged (the voltage is high so, if a torch, it still shines brightly), but then a few weeks later go to use it and find that after a few minutes it dies because the batteries were actually close to being flat after the last use.

Some say NiCds lose 10% of their charge in the first week of self drain, and I assume that continues at the same rate. However, I have not found that to be so. We use NiCd's in torches both on the boat and at home and one of those at home will sit for many months with no use but it certainly holds its voltage and also seemingly its charge over that time. We have a handheld VHF with AA NiCd cells and it holds a great deal of its charge for 6 months or so over winter (in fact it was last used last early May, not charged afterwards until last weekend when I charged it ready for us to go away again - it just needed a top up).

Because of the "sudden voltage death" of NiCd's when drained during use with no obvious signs such as, if a torch, dimming beforehand, we use always non rechargeable cells in things such as Life Buoy lights.

John

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Re: Does anyone publish "What Rechargable Battery" magazine ?

try model shops that do cars and planes, as they have plenty of knowledge and equipment. The capacity, not the voltage, of the cell(battery to you!) will depend on the price, so standard 600s are probably less than £1 each from maplin, but you can get up to 1500/2000 which jump in price. A bog standard slow charger will cost less than £10, and takes about 14hours, but you can get very sophisticated auto discharge /rechargers that do packs and different batteries together from about £30 or up to £100, and take 20 minutes (useful at a car track or airfield), and run off a 12v battery.
Nicads should last more than you ll ever use them these days ( up to 1000 charges they say), ,the hydrides I think are a little more tricky on the fast charging... i d just stick with the good old dependable Nicads. Lastly, an alkaline battery has a sloping discharge curve, whereas Nicads run at more or less full capacity and then drop off very fast. When you say "toys", just bear that in mind if its airborne or afloat...

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