Whats in a battery booster?

[mattylad]

Hi,

I am in need of a new car battery charger - my last one became the victim of something heavy falling on it.

Now before I dig the bits out and rebuild it, I might as well get a completely new one and have seen battery boosters - apparently able to start the car.

Could be useful as mine is always parked down the road.

So whats inside them and how do they work? Do they work?
At £33 ish on the bay - are these any good?

http://www.ebay.co.uk/itm/12V-PORTA...6409?pt=UK_Recovery_Tools&hash=item19e59d7e89

 

[rjm2k]

A battery!

 

[Belle427]

yes, believe it or not its a battery in a box!

 

[Burnerman]

The problem with these things is that they are generally used so infrequently, when you come to need it the internal battery is goosed anyway
John

 

[Peter.N.]

If you need a new charger buy and old heavy one with a meter on it from a boot sale or Ebay, a lot of these modern 'smart' chargers are rubbish, seem to be just a box with some LEDs.

Peter

 

[mattylad]

Well,
I just took apart and reassembled a Halford battery charger with leds

This now works.

So I may just be better of charging a spare battery and using that instead.

Cheers folks.

 

[AlanE]

So I may just be better of charging a spare battery and using that instead

Many moons ago I repaired car radios as part of my occupation and had a car battery, kept charged up, to operate them. I used a mini one as had a mini van at the time.

Car battery gave up the ghost so installed the one used for the repairs. Didn't even have the power to operate lights so be aware that if you keep a spare battery to use as a booster system for a vehicle it may well not work when the time comes to use it!! It continued to power the car radios for several more years however.

Car batteries need to be used as a car battery heavy discharges and recharged in order for them to work correctly.

 

[Peter.N.]

I would agree, for a standy supply you need a deep cycle battery, an AGM type or similar.

Peter

 

[mattylad]

Hmm, flat again today.

I only do 6 miles to work & back again though.

Took it out of the car, tried it with the charger but the charger is just in trickle mode rather than charging and the battery on its own is at 0v.

Cells have fluid in though, the battery is only a year old so I doubt its knackered.

I am currently using my 13.8v radio supply to charge it.

 

[Peter.N.]

six miles should be enough to recharge it, I would suspect either something is draining it or the battery is u/s. Are you getting around 14.4 volts across the battery with the engine running?

Peter

 

[mattylad]

That's a test I need to do yet

IF only this torrent of rain would stop.

 

[Burnerman]

When you get home after a run Matty, disconnect the battery and see if it holds its charge (you may need the radio code of course).
If the battery maintains charge, then its a drain on a system somewhere (frequently the alternator or maybe an interior light). If it doesn't, then its goosed internally.
John

 

[mattylad]

BUGGER!

Had it on my radio PSU last ight but at some point I turned it off to test the battery both using the front panel switch and the socket.

Forgot to turn it back on at the front panel switch but could not tell as the fan and leds were lit anyway.
Zilch this morning.

Anyway - am trying again with a new charger courtesy of Argos (yes I know - crap but the only one I could get).

I hope this sorts it, I'll do more testing at the weekend but I have a longer drive to a customers premises monday & tuesday.

 

[mattylad]

YAY!

Battery back in - charged OK - starts OK - alternator giving 13.8v (OK?)

Seems OK - I hope it stays this way.

I must have left something on.

 

[Burnerman]

14.2v is a better figure Matty......lets see how it is in the morning!
An alternator can charge well enough, but allow current to 'leak back' through its diode pack if faulty.
Be lucky!
John