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-   -   Who makes the best NiCads? (https://www.vintage-radio.net/forum/showthread.php?t=142896)

mole42uk 10th Jan 2018 5:34 pm

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.

IanNVJ35 10th Jan 2018 5:38 pm

Re: Who makes the best NiCads?
 
Definitely the 2000mAh Eneloops - no question. Decent capacity and thousands of cycles.

G6Tanuki 10th Jan 2018 5:46 pm

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.

vidjoman 10th Jan 2018 5:51 pm

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.

kellys_eye 10th Jan 2018 5:52 pm

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.

Nuvistor 10th Jan 2018 5:56 pm

Re: Who makes the best NiCads?
 
Quote:

Originally Posted by vidjoman (Post 1006628)
You could run some cable down to a ground level battery box to save climbing up to replace batteries.

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.

sortedradio 10th Jan 2018 8:22 pm

Re: Who makes the best NiCads?
 
Quote:

Originally Posted by vidjoman (Post 1006628)
You could run some cable down to a ground level battery box to save climbing up to replace batteries.

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

merlinmaxwell 10th Jan 2018 9:23 pm

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Old school nicads are near enough indestructible, I have a load of Sanyo AA size Cadnicas (from an out of date submarine backup battery, I couldn't bear for them to be dumped) that still work after sitting around for more than 10 years after they where out of date.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

PETERg0rsq 10th Jan 2018 10:16 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:

Silicon 10th Jan 2018 11:59 pm

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.

mole42uk 11th Jan 2018 11:36 am

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.

Radio Wrangler 11th Jan 2018 11:41 am

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

vidjoman 11th Jan 2018 12:53 pm

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.

turretslug 11th Jan 2018 12:55 pm

Re: Who makes the best NiCads?
 
Quote:

Originally Posted by merlinmaxwell (Post 1006704)
I have a load of Sanyo AA size Cadnicas (from an out of date submarine backup battery,

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

mole42uk 11th Jan 2018 2:02 pm

Re: Who makes the best NiCads?
 
Quote:

Originally Posted by vidjoman (Post 1006903)
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.

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. :(

dave cox 11th Jan 2018 2:45 pm

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

merlinmaxwell 11th Jan 2018 3:11 pm

Re: Who makes the best NiCads?
 
Quote:

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

G6Tanuki 11th Jan 2018 3:25 pm

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.

merlinmaxwell 11th Jan 2018 5:52 pm

Re: Who makes the best NiCads?
 
Quote:

Originally Posted by dave cox (Post 1006933)
memory effect (of NiCd)

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

turretslug 11th Jan 2018 8:18 pm

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.


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