Battery charging warning· Page 2

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AndyJ23Uk
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7 years ago

#21

"royfellows" wrote:
Genuine though?

yup - all genuine - and 5 years later - still going strong

Morlock
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7 years ago

#22

I think I'll do a test on the the PC power pack cells vs Panasonic. May take a fair while for full comparison.

royfellows
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7 years ago

#23

A funny old thing is that I have an HP Mini 110 netbook and the battery went south a year or so back. All I could find to replace it was a £10 off eBay thing. I expected junk but what I got is quite good.
I wonder if they were genuine surplus or something.

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Morlock
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7 years ago

#24

Certainly look like surplus stock as they came in original packaging. A bargain if they're any good as cost less than 7 pence per cell. Well worth a rummage through the auction site.

http://www.johnpye.co.uk/

🔗113687[linkphoto]113687[/linkphoto][/link]

John Lawson
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7 years ago

#25

Just another thread, Lozz mentioned Vanadium!
This system seems to preferred by the big providers such as National Grid, as an alternative to the South Australia, Tesla set up,
Unfortunately as far as I can see, this system is unlikely to be miniaturised.
Since it seems to need sulphuric acid electrolyte, being pumped between the two halves of the cell.
A company has set one up in Cornwall, and they say it will give instant electrical power, comparable to hydro power!
Also Unlike Lithium ion cells which cannot be discharged to zero, without damage, this Vanadium system can be discharged to nothing. As you say we live I. Interesting times!

royfellows
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7 years ago

#26

Off thread, but relevant to current discussion:

Considering the main parts of a typical Transmission & Distribution network, here are the average values of power losses at the different steps:

1-2% – Step-up transformer from generator to Transmission line
2-4% – Transmission line
1-2% – Step-down transformer from Transmission line to Distribution network
4-6% – Distribution network transformers and cables
The overall losses between the power plant and consumers is then in the range between 8 and 15%.

What can cause confusion is the figure for power loss on transmission. As can be seen from the above this is only part of the equation.

I have to point out though, that is not the major issue with the generation and consumption of electricity, which is the unequal demand between nighttime and daytime.
Main attempts to tackle this have been pumped hydro storage such as that at Llanberis.

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lozz
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7 years ago

#27

The losses are greater in the distribution because of the lower voltages, for a given power the lower the voltage the higher the current, power dissipated (wasted) in the line = Isqrd*R, (I = line current, R = line resistance) From that it can be seen that the higher the current the greater the dissipation in the line.

That current also includes any reactive current, reactance
doesn't dissipate power but the current flowing due to its presence has to flow via the line and the line will dissipate power due to the flow of reactive current because the line has resistance.

Lozz.

DaveM
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7 years ago

#28

The nickel hydride batteries are very good but they have to be charged (ideally) the day before you are going to use them which wouldn't be to everyones liking. Before going underground I always take great care to ensure that both main and spare batteries have a full fresh charge, the last thing you need underground is unreliable batteries.

NewStuff
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7 years ago

#29

You can get LSD (No, not that kind, Low Self Discharge) cells that lose very, very little charge from being left for days, or weeks, even months and years in some cases. The trade-off is that the capacity of the cell's are lower.

Might be a solution for someone. Eneloop are the best known of these.

Searching for the ever elusive Underground Titty Bar.

DDDWH CC

royfellows
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7 years ago

#30

I have just taken a 2 cell Li Ion power bank out of my stock room which was charged on assembly about 2 weeks ago and kept for a customer who doesn't want delivery until after the holiday. The room albeit indoors is unheated.

I have just checked the voltage and got 8.36V.

The cells are 2S Panasonic NCR 18650B 3500mAh

These are OEM cells and are resold with new labels and protection circuits under other brand names.

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Morlock
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7 years ago

#31

Whilst refreshing my understanding of the Vanadium cell I found this little interesting snippet.

From Wiki.

"Lithium Ion batteries, for example, are typically damaged when they are allowed to discharge below 20% state of charge, so they typically only operate between about 20% and 100%, meaning they are only using 80% of their nameplate capacity".

royfellows
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7 years ago

#32

"Morlock" wrote:
Whilst refreshing my understanding of the Vanadium cell I found this little interesting snippet.

From Wiki.

"Lithium Ion batteries, for example, are typically damaged when they are allowed to discharge below 20% state of charge, so they typically only operate between about 20% and 100%, meaning they are only using 80% of their nameplate capacity".

Yes, discharge limit is about 2.6V which is why they require a management circuit.
I warn about putting them away in discharged state whereby voltage could fall below the critical 2.6V

However, comparing them with other battery forms, nothing else at this times holds a candle to them.

Tesla 2170 (21mm X 70mm) have stated capacities of 6250 mAh at the nominal 3.7V.

When comparing different power banks its important to realise that the only meaningful comparison is watt hours as the internal arrangement of cells can vary. You would need this information anyway to take them on a plane.
If a supplier merely states capacity without giving the voltage its completely meaningless.

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Andy Mears
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7 years ago

#33

The most "bomb proof" batteries I've come across are flooded cell nickel cadmium. We used some that had been stood nearly 20 years untouched and they took a charge and worked fine. They were so low voltage wise that the charge regulator from a solar PV panel thought it was a 12v pack not 24v. Had to bodge a diode in series with the panel to get volts up enough for the charge regulator to see it as 24v. 24 hrs later it cranked and started our 52kva genset - over 6 litre capacity and about 20:1 compression. I was quite impressed with that.

Morlock
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7 years ago

#34

NiFe and Edison miners lamp batteries could usually be revived after years of lying about with an electrolyte change and recharge.
Very maintenance intensive once in service though.

royfellows
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7 years ago

#35

I was told a story by SH of Talybont about a chap who wore a NIFE batty under a wetsuit,..... and it leaked.

You wont want to hear the rest, but he nearly died.

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Graigfawr
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7 years ago

#36

My first lead mining trip in 1981 (I'd been surveying other mines since 1976) was lead by SH of Talybont: he loaned me a Nife cell ... it had a manufacturer's plaque with the date '1948' on it and it worked fine all day.

If the electrolyte wasn't so deeply unpleasant, I'd have bought into Nife lighting; instead I went for lead-acid, though for some years I did run ex-MOD Nicads potted into dead Oldham / Exide 'R' type battery bodies when I needed extra capacity for very long trips.

These days its RF's lights and I see features I never noticed previously!

Andy Mears
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7 years ago

#37

Certainly right about the electrolyte - potassium hydroxide, also known as caustic potash and very similar to caustic soda - not the most user friendly of materials.

John Lawson
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7 years ago

#38

When I started ‘mining’ way back, sometimes I think it was before the Ark!
Second hand NiFe lamps were extremely common, since the NCB, had ‘given up on them’, due to their high incidence of causing skin burns. Which was came from alkali, leaking out of the cells.
The problem basically was caused by the seals in them, degenerating ,which allowed some of the electrolyte to leave the battery.
This occurred, especially, if the miner was carrying out a clearance job, or bending down to do the task.
I can remember the late Harry Parker, driving over to deep Ecton mine simply to sit in the water, so that the burn on his back,could, at least be thoroughly washed down.
Needless to say, when I next saw him he had converted to a lead acid lamp, which in effect,is almost completely sealed.

royfellows
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7 years ago

#39

Hi John
I have known the lead acid batteries leak, major cause for concern if brought into contact with ropes.

I think that in retrospect, to talk about "the good old days" one has to cherry pick.
:lol:

Have a good New Year

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RAMPAGE
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7 years ago

#40

Even the Oldham T cells leaked sometimes.

Beneath my steely exterior beats the heart of a dashing hero