RAC Portable Power Station, need DC adaptor spec

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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.

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Adrian C
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Adrian C
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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.

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

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

Adrian C expressed precisely :

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.
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        Harry (M1BYT) (L)
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Reply to
Harry Bloomfield

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

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

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 :-)

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Adrian C
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Adrian C

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
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        Harry (M1BYT) (L)
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Reply to
Harry Bloomfield

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

Reply to
Terry Fields

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

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Adrian
Reply to
Adrian C

I just got a similar unit about a week ago, and you won't likely know what's inside until you open the case.

The Schumacher Instant Power 400 Peak Amps model IP-55 has a 12V 5Ah battery and an internal charging circuit (AC transformer, circuit board, LEDs red-yel-grn).

On the back of the unit, there is a flip-up set of (2) blades that fit a standard NEMA 120VAC extension cord female connector. Any AC cord is just connected to the 2 blades for charging. The manual states that an optional 12V cord is available for charging from a car lighter-socket "while driving" (inserted into the front DC power outlet socket), which won't actually work well unless connected "while driving" while the vehicle alternator is operating and the output voltage is about

13.8-14.2V. Cable p/n 38-99-001564, which doesn't seem to exist.. not found on their site or by Goog search. A warning cautions that the unit's internal charge limiting circuit is not applied when the adapter cord is in use, and the charge-level LEDs aren't functional/reliable, so.. the user needs to disconnect the adapter cord and check the level of charge frequently when using the charging cord, also never used in excess of 4 hours, never unattended - risk of explosion or fire, and disconnected when the engine is not running.

The unit's internal battery is connected directly to the big, external battery terminal clamps, so one needs to avoid contacting the clamps to anything conductive, or each other. The front DC power outlet is connected directly to the internal battery, with a 15A self-resetting circuit breaker in series.

Charging thru the front power outlet socket on these types of power-packs should only be performed by use of an actual smart/automatic battery charger.. one that will charge at a low rate (~1A maximum for a 5Ah battery or C/0.2 rate) and capable of automatically stopping the charge cycle when a fully charged state is attained.

-- Cheers, WB .............

Reply to
Wild_Bill

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.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

Or get a decent RC charger for silly money

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$1Chargers/Chargers/Logic-Fusion-NX81-Variable-Output-AC-Delta-Peak-Charger.ice

variable rate 4-8 cells and hardly bank breaking.

Reply to
The Natural Philosopher

My Silverline 38Ah Jump starter -- and yes, unlike an awful lot of these things, it actually works and will start a 2.5 litre diesel with a flat battery -- has a charger that's marked 15v 500mA.

Reply to
John MacLeod

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

Reply to
Terry Fields

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.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

.

=A0 London SW

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.

Reply to
robgraham

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.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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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.
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<me9

That's because bloody market traders are queuing at the door come opening time to snag all the best stuff!

Ron

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Ron

On 12/2/2010 2:01 AM Adrian C spake thus:

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.

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Reply to
David Nebenzahl

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...

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    Dave Plowman        dave@davenoise.co.uk           London SW
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