waynos 0 Posted August 21, 2006 i know how to check the voltage across the terminals, just wanted to kno how to check the amperage. ive seen them do it in halfords on a multimeter before so i must be able to do it does anyone know how? Quote Share this post Link to post Share on other sites
gaz the geezer 0 Posted August 21, 2006 The voltage is easy enough to check with a voltmeter. If the voltage is between 13.5 and 14.5, it's a good bet the alternator is good. To check the amperage output you will need to `load ` the battery using a drop tester to short the battery and see how quickly it discharges .... if it discharges pretty quickly then it`s a fair bet that the battery is on it`s way :thumbleft: Quote Share this post Link to post Share on other sites
Supercharged 2 Posted August 21, 2006 Take it to Halfords - they do it for free... Quote Share this post Link to post Share on other sites
exturbo2003 0 Posted October 15, 2006 you cant do the amperage of a batterry with a multi meter you can check the amp draw with one but not the capacity of the battery or the amp output from the alternater. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted October 15, 2006 Direct amperage output of a car battery when shorted is in the *hundreds* of amps, and not many multimeters can handle that. Well, certainly not the type you're likely to have at home. If you're sure you want to test the loading capacity of the battery, you'll need a proper battery tester (and some training), or as stated you can get Halfords to do it .. TBH you can learn almost all you need to know about the state of your battery with a multimeter anyway. If it's reading 12.6V then it's fully charged. Every 0.2 drop in voltage equates to about a 20% drop in capacity. So by the time you're down to 11.8V then you're pretty close to where it'll fail to start the car. Quote Share this post Link to post Share on other sites
Deluk 0 Posted October 17, 2006 just get a new one , i got one for 30 bucks but my Dad can get em cheep lucky cus there 90 bucks :D , winters coming in fast you need a good batt, it will just let you down.. Deluk Quote Share this post Link to post Share on other sites
Guest Posted October 17, 2006 just get a new one , i got one for 30 bucks but my Dad can get em cheep lucky cus there 90 bucks :D , winters coming in fast you need a good batt, it will just let you down.. Deluk and throw the old one in a river! no point replacing it if its good, and he doesn't mention it being flat, or unable to start the car. Quote Share this post Link to post Share on other sites
Deluk 0 Posted October 17, 2006 oh mine was shite Quote Share this post Link to post Share on other sites
