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RAC Portable Power Station, need DC adaptor spec

A

Adrian C

Jan 1, 1970
0
http://i912.photobucket.com/albums/ac327/turnstyler/IMG_3573.jpg

A neighbour has dropped in with his discharged and dead "RAC Portable
Power Station and Engine Starter" which he obtained without the
necessary DC charger. The starter is a dayglo orange heavy thing with a
handle and says it can crank 400 Amps.

Anyway, written on the front of the DC input socket, it claims it needs
16V - so I've got it charging up of one of my laboratory supplies set at
that.

Initially connecting it up, it was was drawing about 100mA. After 5
hours it's now drawing 400mA. Must have some 'inteligence' in it.

So I'd guess a 16V 500mA adaptor (or thereabouts) would be a suitable
replacement. But to check if anyone has one of these, could ye check
what's written on the mains adaptor? And can find for reference the user
instructions?

Thanks.
 
D

Dave Plowman (News)

Jan 1, 1970
0
Anyway, written on the front of the DC input socket, it claims it needs
16V - so I've got it charging up of one of my laboratory supplies set at
that.
Initially connecting it up, it was was drawing about 100mA. After 5
hours it's now drawing 400mA. Must have some 'inteligence' in it.

If the internal lead acid battery was very flat, this is what happens. The
internal resistance goes high. As it charges, it comes down to where it
should be. FWIW the SLAs used on these won't supply starting current very
often. Perhaps a half dozen times or so before they no longer manage the
full amount. But can limp on as just a portable 12v DC supply for quite
some time.
So I'd guess a 16V 500mA adaptor (or thereabouts) would be a suitable
replacement. But to check if anyone has one of these, could ye check
what's written on the mains adaptor? And can find for reference the user
instructions?

My Lidl one has a 1000 mA wall wart. I can look at its spec if you want.
 
H

Harry Bloomfield

Jan 1, 1970
0
Adrian C expressed precisely :
Initially connecting it up, it was was drawing about 100mA. After 5 hours
it's now drawing 400mA. Must have some 'inteligence' in it.

That is the usual behaviour of a completely flat lead acid battery,
rather than any built in intelligence. My (not RAC) unit has an
automatic charger built in, which cuts it off once the fully charged
voltage is reached, but yours might not do that (look for an LED marked
charged)- so it might need to be carefully matched in voltage output.
It lights up as soon as powered, then goes out once fully charged and
stays out until powed down and up again.

It's charger suggests it is 18v 0.75amp DC. If yours lacks the charge
control built in, you need a voltage controlled PSU of around 13.8 to
14.2v.
 
D

Dave Plowman (News)

Jan 1, 1970
0
My Lidl one has a 1000 mA wall wart. I can look at its spec if you want.

It's actually marked 12 volt DC 1000mA. So must be a very nominal 12
volts. ;-)
 
A

Adrian C

Jan 1, 1970
0
It's actually marked 12 volt DC 1000mA. So must be a very nominal 12
volts. ;-)

Thanks for checking.

Something unregulated rated at anything past 12V rated at an amp or more
might just fit the task, and be easier to find in the junk pile than
something unregulated and small with specifically 16V stamped on it.

He'll go for that :)
 
H

Harry Bloomfield

Jan 1, 1970
0
Adrian C has brought this to us :
Thanks for checking.

Something unregulated rated at anything past 12V rated at an amp or more
might just fit the task, and be easier to find in the junk pile than
something unregulated and small with specifically 16V stamped on it.

12v or even 13.5v will not put a charge into a 12v lead acid battery,
it needs to be in the range 13.8 to 14.2v
 
T

Terry Fields

Jan 1, 1970
0
Adrian said:
http://i912.photobucket.com/albums/ac327/turnstyler/IMG_3573.jpg

A neighbour has dropped in with his discharged and dead "RAC Portable
Power Station and Engine Starter" which he obtained without the
necessary DC charger. The starter is a dayglo orange heavy thing with a
handle and says it can crank 400 Amps.

Anyway, written on the front of the DC input socket, it claims it needs
16V - so I've got it charging up of one of my laboratory supplies set at
that.

Initially connecting it up, it was was drawing about 100mA. After 5
hours it's now drawing 400mA. Must have some 'inteligence' in it.

So I'd guess a 16V 500mA adaptor (or thereabouts) would be a suitable
replacement. But to check if anyone has one of these, could ye check
what's written on the mains adaptor? And can find for reference the user
instructions?

Thanks.

These days battery chargers are very sophisticated things in how they
treat batteries. If your friend has more than one battery to care for,
an Optimate or Accumate charger might be a good idea, but they aren't
cheap.

TF
 
A

Adrian C

Jan 1, 1970
0
Adrian C has brought this to us :

12v or even 13.5v will not put a charge into a 12v lead acid battery, it
needs to be in the range 13.8 to 14.2v

A biggish transformer marked 12v lightly loaded will be supplying that
and more easily. Got no worries about that (and as I said easier for me
to find).

Cheers
 
D

Dave Plowman (News)

Jan 1, 1970
0
These days battery chargers are very sophisticated things in how they
treat batteries. If your friend has more than one battery to care for,
an Optimate or Accumate charger might be a good idea, but they aren't
cheap.

No need to pay silly prices for a sophisticated battery charger. Lidl and
Aldi in the UK both do similar ones for about 14 gbp. They pulse charge a
flat battery, change to a normal charge, then switch to a maintenance one.
Get the same thing with a 'name' on it and you'll pay four times as much.
 
T

The Natural Philosopher

Jan 1, 1970
0
Dave said:
No need to pay silly prices for a sophisticated battery charger. Lidl and
Aldi in the UK both do similar ones for about 14 gbp. They pulse charge a
flat battery, change to a normal charge, then switch to a maintenance one.
Get the same thing with a 'name' on it and you'll pay four times as much.

Or get a decent RC charger for silly money

http://www.alwayshobbies.com/Boats/...X81-Variable-Output-AC-Delta-Peak-Charger.ice

variable rate 4-8 cells and hardly bank breaking.
 
T

Terry Fields

Jan 1, 1970
0
Dave said:
No need to pay silly prices for a sophisticated battery charger. Lidl and
Aldi in the UK both do similar ones for about 14 gbp. They pulse charge a
flat battery, change to a normal charge, then switch to a maintenance one.
Get the same thing with a 'name' on it and you'll pay four times as much.

As the battery in the appliance seemed to be a SLA, getting maximum
life out of it demands using an appropriate charger rather than a
random wall-wart. I use an Accumate to keep both a SLA and a
motorcycle battery in good order - I don't have any experience of the
Lidl or Aldi chargers.

TF
 
D

Dave Plowman (News)

Jan 1, 1970
0
As the battery in the appliance seemed to be a SLA, getting maximum life
out of it demands using an appropriate charger rather than a random
wall-wart.

Of course. True SLA (gel) should be charged at constant voltage. They're
not so tolerant as car batteries in this respect.
I use an Accumate to keep both a SLA and a motorcycle battery
in good order - I don't have any experience of the Lidl or Aldi chargers.

These things tend to have different brand names depending on who sells
them - but most are simply a wall wart with a few pennies of extra
components. Usually not worth the premium price.
 
D

Dave Plowman (News)

Jan 1, 1970
0
The Lidl /Aldi offerings are good there is no doubt, but they are
never there when you want them !! You have to be on their mailing
list and make a judgement to buy when they are available - and then
they sit around for ages ..... until that magic moment and hey presto
they do the job. Just been there this afternoon to top up a spare car
battery just in case, using one of these I bought probably a year
ago. Serious cold now in Edinburgh and I can see some sluggish
starting coming up.

They're cheap enough to build into the car. I've done this on my
'classic'. With a waterproof mains connector under the rear bumper.

I get emails from both Aldi and Lidl showing their offers of the week.
With some of them you have to get there early.
 
G

Guest

Jan 1, 1970
0
Of course. True SLA (gel) should be charged at constant voltage. They're
not so tolerant as car batteries in this respect.


These things tend to have different brand names depending on who sells
them - but most are simply a wall wart with a few pennies of extra
components. Usually not worth the premium price.
My Aldi power station seems to use a basic unstabilised wall wart. However,
it seems to charge up to a reasonable voltage, then cease charging (or go to
a very low current) I've been using it to power some electronics, and I've
been monitoring its voltage. It seems to cut out somewhere between 13.5 and
14 volts.
 
D

David Nebenzahl

Jan 1, 1970
0
http://i912.photobucket.com/albums/ac327/turnstyler/IMG_3573.jpg

A neighbour has dropped in with his discharged and dead "RAC Portable
Power Station and Engine Starter" which he obtained without the
necessary DC charger. The starter is a dayglo orange heavy thing with a
handle and says it can crank 400 Amps.

I'm surprised nobody has mentioned this yet in this thread, but aren't
those claims for how much current these things will deliver a lot of BS?

I first saw one of these power units a couple weeks ago, when my
neighbor used his to get my van started after he borrowed it and the
battery started going dead. He used it twice, successfully, to
jump-start my half-dead battery. So they do work, apparently. But his
was similarly marked (I think 300 amps). Is there any way that such a
small lead-acid battery could deliver this much juice? I'm skeptical.


--
How To Access Wikileaks

These sites are still up as of 12/3/10:

http://wikileaks.de
http://wikileaks.fi
http://wikileaks.nl
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http://wikileaks.pl

And these IP addresses can be used:

http://213.251.145.96/
http://88.80.13.160/
 
D

Dave Plowman (News)

Jan 1, 1970
0
I'm surprised nobody has mentioned this yet in this thread, but aren't
those claims for how much current these things will deliver a lot of BS?
I first saw one of these power units a couple weeks ago, when my
neighbor used his to get my van started after he borrowed it and the
battery started going dead. He used it twice, successfully, to
jump-start my half-dead battery. So they do work, apparently. But his
was similarly marked (I think 300 amps). Is there any way that such a
small lead-acid battery could deliver this much juice? I'm skeptical.

They vary quite a bit in price. At the cheaper end I've found they will
deliver enough current (when new) to start a car with a flat battery - but
no more than a handful of times. No lead acid battery likes having what is
efficitively (at that size) a dead short across it. And as is common with
so many of these things the battery costs more to replace than the entire
unit.

The one I have is many years old. It won't deliver enough current to start
a car, but still is ok as a self contained compressor for the tyres. And
as a convenient portable 12 volt source for testing things - it will still
supply much more current than my bench PS. And only cost 20 quid...
 
D

David Nebenzahl

Jan 1, 1970
0
They vary quite a bit in price. At the cheaper end I've found they will
deliver enough current (when new) to start a car with a flat battery - but
no more than a handful of times.

So how much current do you think they're actually capable of
delivering--say with the little battery fairly fresh and fully charged?


--
How To Access Wikileaks

These sites are still up as of 12/3/10:

http://wikileaks.de
http://wikileaks.fi
http://wikileaks.nl
http://wikileaks.eu
http://wikileaks.pl

And these IP addresses can be used:

http://213.251.145.96/
http://88.80.13.160/
 
D

Dave Plowman (News)

Jan 1, 1970
0
Too many variables. What is the amp hour rating of the battery?

Tiny in automotive terms.
What is the internal resistance of the switch?
Dunno

The resistance of the
cables?

Mine has 16mm² cables. The resistance of the alligator clamps is more
likely the limiting factor.
The resistance of the starter motor? The temperature? How
clean are the battery clamps, and what is the resistance of the battery
cables? The resistance of the starter solenoid?

Non of which matters since the power pack makers claim a maximum output.
 
D

Dave Plowman (News)

Jan 1, 1970
0
Michael A. Terrell said:
Really? My jump packs have 17 Ah batteries.

I suppose it depends on your definition of tiny, but 17 amp.hr is a lot
smaller than any battery in any car I've owned or seen. Both my current
ones have 70 Ah types.
Product ID: BSL1117
Cold Cranking Amps: 240
Voltage: 12
Termination: NUT & BOLT
Chemistry: SLA OR VRLA VALVE REGULATED S
Weight: 13.3
Width: 2.99
Length: 7.13
Height: 6.57

My truck uses a size 27 battery with these specs:
Product ID: MTP-27
Amps: 1000
Cranking Amps: 1000
Cold Cranking Amps: 810
Voltage: 12
Termination: A
Pro-rata Warranty: 85
Weight: 47.4
Width: 6.81
Length: 12.06
Height: 8.88

So, it has 24% of the rating of the truck battery which isn't
'tiny'.

Err, you don't appear to have given the amp.hr capacity - the very thing
you mentioned.
It is intended to start a vehicle with a run down battery, not
one with mechanical problems.
The portable pack is designed with a
different type of battery, as well. The available current is determined
by the plate area and thickness.
I've seen someone use 12V alarm batteries to jump start a service
truck. They were rated at 7 Ah.

Batteries? Parallel them and they become like a larger one.

No, all of it is important. If the resistance of the clamps is as
high as the leads, they will overheat since all the resistance is at the
same spot rather than distributed along the length of the cables.


BS. They all matter, if you aren't an ignorant troll.

What do you think the short circuit current of a fully charged 12V
car battery is?

Are you trolling? The maker of the jump start pack claims a maximum
current. Since they can't possibly know exactly what the starter motor etc
draw is, just how is it relevant?

My point is (with experience of several jump start packs including
expensive ones) is that they will not do lots of starts of a vehicle with
a flat battery without permanent damage to the SLA. Somewhere round a
dozen or so seems to be it.
 
D

Dave Plowman (News)

Jan 1, 1970
0
You keep changing the subject.

Think you should re-read my posts. Perhaps you addressed your questions to
the wrong person.
 
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