Paging Dr. Ivan - re : Power Station

Just for info, mate:

Netto are doing a "power station" car charger thingy for 20 quid (5 quid
cheaper than Aldi).
In the shops tomorrow.

Dave

 

Ta. In the event I've decided to give it a miss this time around,
and I'm not sure where my nearest Netto shop would be[1], but still thanks
anyway.

Hmm, it doesn't say in the ad and you can't read it in the photo
on the web, but I'm sure the in-store flyer photo specs the Aldi's battery
capacity at rather more than the 17 AH of the Netto's. Black Kat's
battery is 11 AH, and I remember noting that the Aldi device had several
times that capacity.

[1] South Harrow, beating Acton, I think -- I passed through both on the
Picc line tonight and SH is definitely closer.

--
Ivan Reid, Electronic & Computer Engineering, ___ CMS Collaboration,
Brunel University. Ivan.Reid@[brunel.ac.uk|cern.ch] Room 40-1-B12, CERN
GSX600F, RG250WD "You Porsche. Me pass!" DoD #484 JKLO#003, 005
WP7# 3000 LC Unit #2368 (tinlc) UKMC#00009 BOTAFOT#16 UKRMMA#7 (Hon)
KotPT -- "for stupidity above and beyond the call of duty".

 

Hmm, there may be an obscured decimal point in the photo; is it
172 AH or 17.2 AH? Given what I remember of a 100 AH battery's size, I'd
have to guess it's the latter, so they do have the same battery capacity.

--
Ivan Reid, Electronic & Computer Engineering, ___ CMS Collaboration,
Brunel University. Ivan.Reid@[brunel.ac.uk|cern.ch] Room 40-1-B12, CERN
GSX600F, RG250WD "You Porsche. Me pass!" DoD #484 JKLO#003, 005
WP7# 3000 LC Unit #2368 (tinlc) UKMC#00009 BOTAFOT#16 UKRMMA#7 (Hon)
KotPT -- "for stupidity above and beyond the call of duty".

 

I'm not an electrical expert, but I think its the "cranking power"
that's significant.

FWIW, a friend bought one a few years ago.
He's used it, successfully, to start his neighbours lorry......

Dave

 

Big Dave wrote

For cranking power Sir needs 24V.

A standard trick employed by pikey mates of mine who used to run shite
old lorries was to have a separate 24V system just for the starter
motor. Guaranteed even to bring and old BMC 3 tonner to life at the
twist of two heavy duty cables that was.

 

hmmm. 400A for not very long, then.

about 2.5 minutes, I make it.

 

That, I did not know.
Useful info.
Thanks matey.

I've just sent SWMBO down to local Netto to pick one up for me - if there
are any left......

Btw :
Useful Tip No 47563529 :
As told to me by a mate who was been selling mobile phones for aboutr 20
years.
Did you know that you can "recover" apparently knackered NiCads (eg: mobile
phone batterie) by freezing them?
You stick the battery in a freezer bag, then lob it into your common or
garden domestic freezer.
Leave it there for 3 or 4 days minimum (a week is better). Take it out of
the freezer and out of the bag.
Let it come up to room temperature on its own.Then stick it on charge for 24
hours.
Bingo! Almost as good as new!
I've tried it several times and it works.
Apparently, during normal use, bubbles form in the gel and act as a barrier
between the "gel" and the "plates" (if NiCads use plates? I dunno)
The bubbles disperse at low temperatures. Which ius why freezing restores
the battery. Or so I'm told (I'm not a battery expert_
But....You should remember that, eventually NiCads do get knackerd. Freezing
won't work then.

Taraa Then
Dave

 

hmmm. battery on the bike is a bit on the flat side, mind, it's not been
started in about 3 months. I've stuck the charger on it. Hopefully, it
won't require freezing - not sure that's good for lead/acid ones.

hopefully2 it'll start after a bit of a boost. I need one of they Power
station things, innit.

 

LOL (again)

You could always try putting the bike in the freezer.........

Dave

 

Big Dave wrote

I have tested the recharging of NiCads under various conditions a bit
and have also tested what happens when they are cold. To a certain
extent cooling a battery allows faster and charging and an apparent
improvement in capacity.

This improvement in capacity of a fully charged NiCad seems only to hold
for that charge (I only needed it to hold for half an hour) but not for
subsequent charges.

Worth noting that most of the time half an hour in the freezer
immediately prior to charging or a dribble of freezer spray during fast
charging situations. I didn't notice any extra gain from doing both.

 

heh

Jump-started it from a big battery to get it fired up, ran it a bit at a
couple of thousand. Then went and had lunch.

After lunch it fired from it's own battery, I then blew the tryes up
properly and went to Swansea ( 'bout 40 miles) - Pulled 85 on the motorway
and not at full chat, so not a lot wrong with the ol' beast - 's not be
started for about 3 or 4 months, so a good idea to blow the cobwebs out..
Good German Engineering, I reckon.

and by **** it was cold on the way home about 9 o'clock.

 

RC modellers do this with car batteries.

A common failure mode in NiCds is dendrite (spiky crystal) formation,
which bridges the plates. In the big ones you can blow the crystals away
by shorting them for an instant (but watch out for spot welding the
contacts together!), but many domestic batteries (like phone and camera
ones) can't be fixed this way because of the internal fuses.

So if freezing destroys the crystals, then it might genuinely work.
Trouble is that if dendrites have formed once the cell will form them
again more readily than before, so it's a temp fix really for a cell on
the way out.

Be interesting to look when I get a moment to see if there's any
write-ups on the net.


Regards,

Simonm.

 

So that's how it works.
I was told bubbles.
No-one mentioned dendrite.
Trust me though, freezing /does/ work.
Really!

Dave

 

< oh s**t! moment >

I meant to say that RC modellers do this with RC NiCd car batteries -
not lead-acid!

[to self] Switch off silly pillock mode before spouting next time...

Regards,

Simonm.

 

SpamTrapSeeSig wrote

Similar environment, spinning a propellor rather than wheels and using
low capacity ordinary batteries against your matched red cell packs.

Yebbut does it?

My pet theory is that there are little cave like structures on the
surface of the plates and the gassing/spike growth/whatever it is can
form in such a way as to prevent access to these areas during (abusive)
charging (cycling) and that cooling in particular is a way of putting it
off a bit, in some circumstances.

Totally engrossing I am sure.

 

Once tried to fix a big NiCd battery (wet cell), well stuffed by the
owner leaving it connected to a solar panel. Not recommended, especially
in the Himalayas. Deep discharging and distilled water improved things a
bit, but not as much as a few big sparks might have done.

It turns out the wet ones are particularly good at dendrites, and the
workaround would've been shorting it, but I didn't find out till I got
home . Sent him a pack made of Cyclons, which love trickle charging.

No net in those days...



Regards,

Simonm.