# starter battery charging?



## relay (May 9, 2005)

Hi
Should the starter battery charge on hook up? Mine doesn't seem to be charging at all. I've driven 70 miles and been on hook up for 16 hours and it's only showing 12.3. At what level would it fail to start the engine? 
Thanks
-H


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## bigbazza (Mar 6, 2008)

My Autotrail doesn't charge unless I select it from the control panel.


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## relay (May 9, 2005)

Thanks but my control panel doesn't have a selection for that, unfortunately. Would it not charge with the engine running anyway?
-H


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## grizzlyj (Oct 14, 2008)

I would think 12.3 isn't far off what an alternator would charge to, (12.5 maybe max?) so not in too bad a condition IMHO


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## pieterv (Feb 3, 2009)

Alternators will charge to a considerably higher voltage, but battery voltage will drop back to about 12.8V for a fully charged battery.


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## erneboy (Feb 8, 2007)

Maybe your alternator is not doing all it should. Do you have a multimeter, if so you can test to see. If not consider buying perhaps, a tenner or so will buy an adequate one.

To test and see if the alternator is charging. Use your multi meter to check the voltage at the cab cigarette lighter with the ignition on but without the engine running. Put the red probe (+ve) into the centre of the outlet, don't touch the side doing that or it will cause a short circuit, just put the probe straight down the middle. Touch the black probe (-ve) to the metal side of the out let. If the meter gives a minus reading the probes are the wrong way round. It should read between 12.5 and 12.8 volts if the battery is in a good state of charge.

Now start the engine and test again. If the alternator is giving a charge the voltage should rise quite a bit. Now it should show between 13 and 14 volts. If that isn't happening the alternator is not charging properly.

Hope that helps, Alan.


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## Wizzo (Dec 3, 2007)

My guess is that your starter battery is well past its best. If your alternator were not charging at all then the starter battery would eventually run out altogether. 

Find a decent local battery shop and ask them to check it for you and to check the alternator output whilst they are at it.

JohnW


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