Checking Battery is holding charge
in [Car Maintenance]
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From: Harry Bloomfield on 27 Jul 2010 14:54 John was thinking very hard : > On Mon, 26 Jul 2010 22:44:44 +0100, "Mrcheerful" > <nbkm57(a)hotmail.co.uk> wrote: > >> John wrote: >>> Can anyone give me any advice on how to check car battery is holding >>> its charge? Can I do this with just a basic multimeter? The cables on >>> the multimeter I've got are quite thin... would i be okay hooking >>> these up to a car battery or would they fry away? >> >> if you want to test whether the battery is in good condition then take it to >> any car shop, they will have a tester. or an AA patrol. > > do they have special testers? is a multimeter no good for checking > this? They have a special type of meter which applies a large load current and checks how much the voltage falls on load over a set period. They will usually carry out the test for free, on the off chance you may buy a new battery if it is demonstrated to be faulty. You cannot do that with an ordinary cheap multimeter, all you can do is check the static volts. It should read something better than 12.5v after standing for a while, but it is not absolute proof that it is OK, just an indication that it is retaining some sort of charge. When cranking, but not actually started it should be over 10.5v. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk
From: Duncan Wood on 27 Jul 2010 15:30 On Tue, 27 Jul 2010 19:54:14 +0100, Harry Bloomfield <harry.m1byt(a)nospam.tiscali.co.uk> wrote: > John was thinking very hard : >> On Mon, 26 Jul 2010 22:44:44 +0100, "Mrcheerful" >> <nbkm57(a)hotmail.co.uk> wrote: >> >>> John wrote: >>>> Can anyone give me any advice on how to check car battery is holding >>>> its charge? Can I do this with just a basic multimeter? The cables on >>>> the multimeter I've got are quite thin... would i be okay hooking >>>> these up to a car battery or would they fry away? >>> if you want to test whether the battery is in good condition then >>> take it to any car shop, they will have a tester. or an AA patrol. >> >> do they have special testers? is a multimeter no good for checking >> this? > > They have a special type of meter which applies a large load current and > checks how much the voltage falls on load over a set period. They will > usually carry out the test for free, on the off chance you may buy a new > battery if it is demonstrated to be faulty. You cannot do that with an > ordinary cheap multimeter, all you can do is check the static volts. It > should read something better than 12.5v after standing for a while, but > it is not absolute proof that it is OK, just an indication that it is > retaining some sort of charge. When cranking, but not actually started > it should be over 10.5v. > Although that normally tells you all you need to Know :-)
From: Dave Plowman (News) on 27 Jul 2010 18:58
In article <mZCdnXTDRLWAtNLRnZ2dnUVZ8rmdnZ2d(a)bt.com>, John <none(a)inuse.com> wrote: > John wrote: > > On Mon, 26 Jul 2010 22:44:44 +0100, "Mrcheerful" > > <nbkm57(a)hotmail.co.uk> wrote: > > > >> John wrote: > >>> Can anyone give me any advice on how to check car battery is holding > >>> its charge? Can I do this with just a basic multimeter? The cables > >>> on the multimeter I've got are quite thin... would i be okay hooking > >>> these up to a car battery or would they fry away? > >> > >> if you want to test whether the battery is in good condition then > >> take it to any car shop, they will have a tester. or an AA patrol. > > > > do they have special testers? is a multimeter no good for checking > > this? > No, you need something like this > http://www.uni-max.co.uk/heavy-discharge-600a-car-battery-and-electrical-system-tester/d/ That's old hat. For about the same price you can get an electronic tester little larger than a DVM. It gives the actual capacity of the battery too. -- *If PROGRESS is for advancement, what does that make CONGRESS mean? Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound. |