bignoel Posted August 20, 2010 Report Share Posted August 20, 2010 i had this problem last year and it appears to be back out lamping the other night and the lamp i think killed the battery .if its my alternator how will i test it for sure as i have been lamping all year and it hasnt affected the battery till now . Quote Link to comment Share on other sites More sharing options...
J@mes Posted August 20, 2010 Report Share Posted August 20, 2010 get the engine running and put a volt meter across the battery - it should be about 13.5 - 14v. then, with the engine running, turn everything electrical on in the car - lights, wipers, get someone to do the windows, radio, heater blowers, heated screens (and seats if you have them) plug your lamp in to the fag lighter and test it again. If it is below 12.5 I would say there is a problem. the best way to do it is with a drop tester, as that is basically a short circuit on the battery with a volt meter on it to show how far it drops with a huge load on - but I doubt you'll be able to get hold of one. If you don't have a volt meter, go to a local garage and ask them to test it. They'll probably do it for free, hoping that if they find a fault they'll get the work. Quote Link to comment Share on other sites More sharing options...
al4x Posted August 20, 2010 Report Share Posted August 20, 2010 if you're in a fourtrak hasn't it got a voltmeter on the dash? though in simple terms if its knackered the battery light usually either stays on or takes a lot longer to go out Quote Link to comment Share on other sites More sharing options...
bignoel Posted August 20, 2010 Author Report Share Posted August 20, 2010 thats the thing the voltimeter reads fine the battery light comes on with ignition once fired up stays on one rev up it goes out Quote Link to comment Share on other sites More sharing options...
rodp Posted August 20, 2010 Report Share Posted August 20, 2010 Is the fan belt tight? All connections CLEAN and tight? If I remember correctly an alternator can generate correct voltage but low amps IE 13.5 volts but just not enough of them. Of course, the alternator just may not be big enough. Work out how many amps you use and see what the alternator produces (watts divided by volts = amps, therefore 100 watt bulb at 12v = 8 amps app) Quote Link to comment Share on other sites More sharing options...
bignoel Posted August 20, 2010 Author Report Share Posted August 20, 2010 cheers guys but i think a trip to the garage is in order Quote Link to comment Share on other sites More sharing options...
Celticranger Posted August 25, 2010 Report Share Posted August 25, 2010 i had this problem last year and it appears to be back out lamping the other night and the lamp i think killed the battery .if its my alternator how will i test it for sure as i have been lamping all year and it hasnt affected the battery till now . You need to check the AMPS. There is a meter on Ebay which you clip around the main lead from your Alternator, no dismantling required, and it gives the Amperage. You only have to check the specified output for your Alternator. I had the same problem on my Rangerover, volts were reasonable, but Amps low. Put on a high output Alternator off an air condition Rangey, problem cured. I assume you have no problems starting in daylight, if so Batterry must be ok. Oh meter is about £22 to buy, well worth it. Garage charge £90 average!!! Quote Link to comment Share on other sites More sharing options...
covlocks Posted August 25, 2010 Report Share Posted August 25, 2010 Garage charge £90 average!!! Thats a main dealer price - not a general aftermarket garage. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.