Who makes the best NiCads?
 

Or NiMh for that matter.

I will be installing a weather sensor on the top of my house which has a solar charger. I want to ensure that I don't have to replace the batteries for as long as possible. I need AA size cells and wonder which to buy?

Any guidance would be welcome.

Re: Who makes the best NiCads?
 

Definitely the 2000mAh Eneloops - no question. Decent capacity and thousands of cycles.

Re: Who makes the best NiCads?
 

I'm currently using 2450mAh Energizer AA NiMH as my 'default' AA battery. They seem to handle high-current-drain/deep-discharge OK and are cheap.

Don't bother with NiCd - they're old technology that's well past its install-by date.

Re: Who makes the best NiCads?
 

You could run some cable down to a ground level battery box to save climbing up to replace batteries.

Re: Who makes the best NiCads?
 

If you get the opportunity to make physical comparisons then the best method - or so BigClive says - is to weigh them. Chose the heaviest. At the same time, he also recommends the Eneloops too.

Re: Who makes the best NiCads?
 

That was my thought, however it depends on how easy roof access is, a flat roof with a door onto it would be ok, a sloping roof with access by ladders and roof ladders is for me out of the question.

Re: Who makes the best NiCads?
 

Voltage drop on the cable could be a problem. If adopting this approach I would test at ground level, with the appropriate length of cable between the unit and battery box

Re: Who makes the best NiCads?
 

Old school nicads are near enough indestructible, I have a load of Sanyo AA size Cadnicas (from an out of date submarine backup battery, I couldn't bear for them to be dumped) that still work after sitting around for more than 10 years after they where out of date. You are more than welcome to a few (send me a PM).

Re: Who makes the best NiCads?
 

Problem with NiMh in such an application is their high self discharge, and poor memory effects.

Lots of really poor quality NiMh knocking around.

Sometimes "old skool" is just better :shrug:

Re: Who makes the best NiCads?
 

Some of the modern NiMh cells come pre-charged and they hold their charge on the shelf for about 6 months.

Have a look at the Panasonic range.

Re: Who makes the best NiCads?
 

Thanks for all your replies.
Cable isn't a viable option, although I would prefer it, so the solar charge is the best choice. Cost isn't the primary factor, neither is high-current or deep discharge. Length of service is important because I don't want to get the roof ladders out any more often than I have to these days.
I prefer NiCad since I used to design chargers for them years ago and I understand the technology better than NiMh or Lithium.

Re: Who makes the best NiCads?
 

Few firms now make NiCads because of the cadmium content, and the potential liabilities of working with the stuff.

NiMH have got, as said earlier, a nasty self-discharge characteristic.

It sounds like you have a job for a primary cell. It's got to last for decades, there is no re-charging power source. How about the energizer lithium based AA cells? They survive decades in storage and they hold their performance better at low temperatures than anything else.

For high reliability batteries, look at Tadiran of Israel.

David

Re: Who makes the best NiCads?
 

I was suggesting (in post 4) to run a cable to an accessible battery box, but still connected to your roof unit and solar charger. It may be several years before you need to change the batteries but you won't need to get on roof to do it.

Re: Who makes the best NiCads?
 

Is that "submarine" the adjective, or "submarine" the noun? The latter leaves me with a wry smile as to scale....

Re: Who makes the best NiCads?
 

Unfortunately, because of the location, it would be difficult to run a cable and if I did, it would be just as easy to connect to a mains PSU and avoid batteries altogether. :(

Re: Who makes the best NiCads?
 

For AA size MH, historically, I found the top dog was Uniross. As you have solar recharging I doubt self discharge will be a problem but memory effect (of NiCd) would be so I would go for either MH or lithium (=3 AAs). I imagine the ones with the lower claimed capacity will last longer. I bet either the solar cells or the electronics will have you on the roof long before the batteries give out !

dc

Re: Who makes the best NiCads?
 

From a sinky boat thing, mind you they (the cells) would sink too! They are AA size to put it into perspective (not a 3D projection but scale).

Re: Who makes the best NiCads?
 

If the batteries are going to spend their entire life outside, I'd look at the relative temperature-performances of the different technologies: some become distinctly flaky as the temperature gets down around zero. Cold weather plus short hours-of-daylight-for-solar-recharging could cause issues?

See ftp://ftp.noc.soton.ac.uk/pub/autosu...Comparison.doc

https://www.theregister.co.uk/2009/0...m_beneath_ice/

The first generation of Autosub used ordinary D-cell alkalines in part because they suffered lower loss of usable capacity as the temperature fell.

Re: Who makes the best NiCads?
 

is a myth... https://en.wikipedia.org/wiki/Memory_effect

Re: Who makes the best NiCads?
 

I'm assuming that the reason for specifying AA cells was to fit into a (hopefully well-sealed!) existing battery-holder- is there any scope for removing contact springs/partitions etc. in order to fit a welded-link/heatshrunk pack as available in various permutations for back-up use, that would at least eliminate one source of long-term problems, i.e. contact iffyness. Such packs may also be characterised for a wide temperature range, though more likely in the high temperature direction, e.g. being gently braised next to the transformer in a compact emergency lighting fitting.

Re: Who makes the best NiCads?
 

It is amazing how many old documents people leave lying around ;)

In Autosub's case we would prepare the sub in a warmed container so they would have been at 15-20 degrees when they hit the water and their self heating (due to the few hundred watts taken by the propulsion motor) would keep them at higher than ambient temperatures during a mission. Later versions of the vehicle used Kokam Lithium Polymer cells but these haven't been used under ice (although they have been used in the deep ocean where the temperature is mostly around 2-4 degreesC).

Re: Who makes the best NiCads?
 

I've found NiCd difficult to get hold of now, but when they were widely available the Sanyo Cadnica in Yellow were superb.

I use NiMh now and have sampled a few brands, but I've had best results & longevity from the Sanyo or Panasonic Eneloops (same thing) - but beware of counterfeits.

Re: Who makes the best NiCads?
 

You can still get the old Sanyo Cadnica NiCd cells. Panasonic bought out the rights to the Sanyo name.

https://uk.rs-online.com/web/p/c-rec...eries/3777933/

Still lots of advantages to NiCd cells: easy to charge, reasonable self-discharge rate, pretty reliable and work in very low temperatures, almost impossible to knacker. I used them for years in radio control stuff and CB equipment.

EU is cutting down on them though; you can't ship them in new products. Only available as replacements now. This is due to the nice oodles of toxic cadmium in them. Can still recycle the things; no one wants to do it though.

Now we have low self-discharge NiMh like Eneloops, things are quite a bit nicer environmentally. Considerably more of a dick to charge though.

Oh need to add something here: NiCd cells don't have a memory like everyone thinks they do. I have experimented with this extensively with probably 100 or so NiCd cells from Sanyo towards the end of the 1990s and there is no evidence to support this actually happens.

Re: Who makes the best NiCads?
 

Ni-Cds and low temperatures. Maybe the chemistry improved over the years but those folk interested in Clansman radios will know that they use Ni-Cd batteries and the radios came with a battery extension lead for use in "low" temperatures when the poor squaddy was supposed to stuff the battery inside his jacket to keep it's temperature up. A Clansman battery inside one's jacket must be the most uncomfortable thing I can think of!

Gordon

Re: Who makes the best NiCads?
 

I as under the impression that whilst fast charging of Ni-Mh batteries needs to be done intelligently trickle charging them does not and as such can be treated just the same as Ni-Cd batteries, I'm free to be corrected though.

Another good source of Ni-Mh are LIDL, cheap and high capacity, 2300mAh low sef discharge and 2500 normal Ni-Mh AA/AAA's 4 for £2.99, or 6 for about 4.99 or so of the multi coloured ones.

Re: Who makes the best NiCads?
 

Hello.
The Lidl ones are better than the offerings from Energiser and Duracell. They are marked Tronic, some of the earlier ones failed quite quickly but any I have bought in the last two years appear to be from a different source and are greatly improved.

Re: Who makes the best NiCads?
 

Ni-Cads and other "toxic" batteries were banned from import into the EU in 2008, so I'm surprised that some are still available.

If you really need to read up on it:
http://eur-lex.europa.eu/legal-conte...EGISSUM:l21202

Re: Who makes the best NiCads?
 

No discussions about the EU please. It's a very divisive subject in the UK.