kgeddes
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Hi, 2008 L322 TDV8, alternator will not charge new battery beyond 12.3V and I’m experiencing battery drain of 0.1 to 0.3V overnight. Is a new alternator required? Thanks
Battery charging TDV8
- Thread starter kgeddes
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is the charge light lit on the dash with the engine running?
check the main output connection on the alternator to the body of the alternator with a volt meter, if it reads <13v then yes, the alternator is probably dead
check the main output connection on the alternator to the body of the alternator with a volt meter, if it reads <13v then yes, the alternator is probably dead
kgeddes
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thanks for reply. No light on dash. Alternator charging at 14.7 to 14.9 but battery not charging above 12.3V even after two hour drive...battery is two weeks old
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ah, sorry, i thought you meant the battery was at 12.3v while running.
take the battery off and put in on charge for 24h, then leave it for an hour and check again. if its still saying 12.3v then take it back to the shop
take the battery off and put in on charge for 24h, then leave it for an hour and check again. if its still saying 12.3v then take it back to the shop
kgeddes
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thanks again, this is a replacement battery as there were doubts about the previous one which ended up the same way!
is there something in the alternator that’s restricting the charging level to the battery... maybe a fault diode?
thank you
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are you getting 14.7v at the battery terminals when the engine is running? If not then you need to check the lead from the alternator to the battery +ve and engine earth.
the alternator isn't designed to fully charge a flat battery, it needs to be fully charged to start with.
if you take the battery off (disconnect) and make sure its fully charged, you have a base to start from.
how old was the previous battery?
the alternator isn't designed to fully charge a flat battery, it needs to be fully charged to start with.
if you take the battery off (disconnect) and make sure its fully charged, you have a base to start from.
how old was the previous battery?
kgeddes
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the old battery was only 2 months old when I couldn’t start the engine - had to jump start it. I’m using a Sealey AK500 (plug onto cig lighter socket) to check it....always get 14.7 to 14.9 with engine running. Battery will not charge above 12.3V. I’ve also used a Carsoft reader via Obd Port...same readings.
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did you check the batteries when they were new, before you put them on the car? dare i ask the retailer? and did they check the old battery before replacing it?
kgeddes
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both batteries were checked before installation by local garage (I witnessed the results) both read 12.9v before being fitted...I’m confident the battery is ok.
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Battery test should include CCA / EN info to properly indicate condition. Static voltage simply indicates state of charge at the time.
As Kermit says you need to check voltage at alternator and battery to get an indication of charging. Using an ammeter also helps, but with the engine running measuring at the battery cables gives the combination of charge current minus the load from engine & other ECU's. Alternatively current in the alternator cable give charge current plus all the ECU's, etc. Measuring both ends can give a good indication of the charging.
As Kermit says you need to check voltage at alternator and battery to get an indication of charging. Using an ammeter also helps, but with the engine running measuring at the battery cables gives the combination of charge current minus the load from engine & other ECU's. Alternatively current in the alternator cable give charge current plus all the ECU's, etc. Measuring both ends can give a good indication of the charging.
kgeddes
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Thank you
