Car battery charger.

[#1]

I need a charger for a car battery, however I'm confused by the ratings, can anyone help please?
One says 12v 4amp ( simple enough-I understand that). The other says 12v 14-120ah (I don't understand the ah part).
Which one puts out more power ie which one will charge a battery fastest?  Any ideas ? Please not too technical as my eyes glaze over and my mind wanders 

[#2]

I did some similar research a while ago and I ended up with a CTEK MSX 3.8
Superb machine as it's tiny, and performs all the steps in order to charge and maintain a healthy battery.

[#3]

The ah one will work with virtually any car battery. AH is AmpHours, batteries are rated in them, the higher the number the bigger the battery.
So a 60AH one will supply 1 amp for 60 hours. A 120AH one 120 hours etc.
4A is about the min I would want to connect, 8-10A will charge faster, but they are expensive. A 4A one will take all day to charge the battery.
I use one I got from Aldi, it is "cpu controlled" and drops to a trickle charge when the battery is up to voltage.

[#4]

I`m with HB on the 4amp being a "minimum" charger... and his advice for 8 or 10 amp is good.... Used to be a CarParts Shop Manager,... and would often get 4 amp chargers returned as they just couldn`t put enough in to a battery in the short time the customer expected... i.e. half an hour because they forgot to switch the sidelights off last night, and car wouldn`t turn over this morning. and I needed to get to work....
Yeah.. I know.. and 8 or 10 amp would not have fully charged the battery, but might just have got them out of the driveway ! !  and of course, they would have a quicker charge rate the next time they wanted it...
Modern car batteries are a whole lot different to how they were 20 or 30 years ago... the charging systems on modern cars are much more efficient... so.. if your battery is groaning under the starting weight it is time to replace it.... charging it up will only delay the inevitable... and once you have your nice shiny new charger costing 30 to 40 quid... you probably won`t need it again, for at least 2 or 3 years...  You could add that price to your new battery, and get a top of the range replacement, which should last at least 5 years...

[#5]

I have one similar to this which may be a bit of an overkill but charges at 8 amps.
It does various checks before applying the charge and drops to trickle afterwards.
I agree with shutter. I have used my charger 3 times (others have borrowed it more) and since changing my car I haven't needed it once
But it's there if I do.

[#6]

Thanks guys. Looks like I may be getting this
http://www.argos.co.uk/m/static/Product/partNumber/7404355/searchTerm/Car+battery+charger.htm
I bought a calcium battery about three years ago from Halfords, not cheap but worth the money. Unfortunately I left the car for three months without running it and the battery is flat. I've tried jump starting it and going for a run but that's not putting enough charge in, so going to need a charger.

[#7]

You didn't fancy this one then

[#8]

Strangely enough - NO!
If I paid that sort of money for a 'boy's toy' my wife would have some interesting new earrings (and I would have a squeaky voice).

[#9]

Hmmm..... what is the Ah rating for your car battery then?   

Quote

Product Description/Spec Challenge 6V/12V Automatic Car Battery Charger. Short circuit, reverse polarity and overload protection. Charge rate 6 amps RMS. Mains operated.     Suitable for petrol engines up to 1800cc and diesel engines up to 1400cc.     Suitable for 6V/12V batteries and batteries with a capacity of 15 - 80Ah.     Charge time up to 16 hours.     Short circuit protection.

Will this one be "man" enough for the job  ?    ?  ?  ?

[#10]

You can get an idea here http://www.batterymegastore.co.uk/wizard/Car+Battery+Finder/

[#11]

Bought one of these for my diesel yesterday as my old one was a bit tired, happy to be able to listen to my Radio again without the battery going flat!
Good job I live on a hill.

Part Number: YBX3110
Alternative Refrence: 110, 58043, HB110, HCB110,
Voltage : 12v
Ampere-Hour Capacity at 20hr rate Ah: 80Ah
Cold Cranking Performance (Amps) SAE/EN1: 720A
Dimensions LxWxH: 317 mm x 175 mm x 175 mm
Terminal Layout: Negetive (-)  on left, Positive (+) on right ; with the terminals on the edge of the battery closest to you
Terminal: Standard Round DIN post
£62.50 from my local motor factors
I wouldn't waste my time with anything less than an 8 amp charger.

[#12]

This is my battery... http://www.halfords.com/motoring-travel/bulbs-wiper-blades-batteries/batteries/halfords-calcium-batt...
So hopefully the challenge one will do. Still 'umming and aaahing!! 

[#13]

Quote

Bench Charge: 6.8 Amps

So.... Challenge could be the right name for the charger...  rated at 6 amps... but probably only pushing 5 amps when delivering charge... 

[#14]

Just to throw a spanner in the works...http://www.eurocarparts.com/mobile/battery-charger

[#15]

Upon seeing this thread I decided to blow the bank and buy a new battery for my diesel. It has been struggling in the morning and the voltage was dropping so far the alarm reset - meaning I had to switch off and re-start to reset it, luckily the 2nd start was always quicker. I know the better weather means the engine will be that bit warmer but we are going on holiday in 2 weeks and don't want a flat battery when camping.
So ordered a new battery from batterymegastore, £43.61 delivered with a 4 year guarantee. They just called to say it is OOS so are sending a "better" battery for the same cost.