Whats the easiest and best way to check for a drain on the battery? Had a couple of starting issues this winter, 1 i know was from the mrs using it for lots of short journeys with every bloody thing on, heater,seats, stereo blah blah, got it started and put some life back in but wouldnt start last week again. Mr AA suggested checking for any drain, whats the best way to do this? And does it need to be parked and off for a while before doing it, to make sure all the PC's/etc have shut down fully? Think he said leave it 30 mins?
L322 - How to check for battery drain
- Thread starter mrblonde
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Datatek
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Just as likely to be a duff battery. To check drain the safest way is with a clamp meter that goes round the battery cable, then you don't have to disconnect the battery. With a normal meter you set it to amps, remove one battery lead and connect one meter lead to the battery and the other to the lead you have removed from the battery.
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Clamp around DC ammeter over the negative lead.
Datatek
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That's wot I said
Cheers guys
Data it was a new battery last winter, cost about £150 wanted the best I could get at the time, so hoping its not that already? Mr AA said alternator is charging OK so its not that, just seems to be after 5 or 6 days of not being used, especially on these cold mornings...... used it for loads of short journeys summer just gone (3 or 4 trips a day), no problem, just had couple of problems since the cold arrived
Is there a minimum or max reading I should be looking for on the clamp meter around the neg cable?
Data it was a new battery last winter, cost about £150 wanted the best I could get at the time, so hoping its not that already? Mr AA said alternator is charging OK so its not that, just seems to be after 5 or 6 days of not being used, especially on these cold mornings...... used it for loads of short journeys summer just gone (3 or 4 trips a day), no problem, just had couple of problems since the cold arrived
Is there a minimum or max reading I should be looking for on the clamp meter around the neg cable?
Datatek
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Not sure on the L322, but on the P38 it's 30ma after all has gone to sleep. If the battery has been hammered with a lot of short runs so it has never been fully charged it may well be on it's way out. Battery capacity is always reduced when the temperature is down.
Check your alternator belt. Make sure its not all craked and decaying. Thats the first place i'd start. Second to that i would have someone check the alternator itself. The belt is usually the culprit, followed by the alternator. I would say the battery is the usaul culprit but you say its fairly new so...
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dave4x4
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Do a search on Ebay for a "car fuse current amp meter". Useful bit of kit IMHO.
Pull one fuse at a time and plug it into each in turn to see what current is being used.
Pull one fuse at a time and plug it into each in turn to see what current is being used.
2.0_hippo
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might also need a fault code reader so you can clear any faults that may arise from pulling random fuses
dave4x4
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Hi mrblonde,
No sorry. Not very knowledgeable about the L322.
I know the p38 uses standard size fuses.
I would recommend the gizmo as it saves clamp on meters and disconnecting the battery.
No sorry. Not very knowledgeable about the L322.
I know the p38 uses standard size fuses.
I would recommend the gizmo as it saves clamp on meters and disconnecting the battery.
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dave4x4
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No. You put the fuse you have pulled back into the end of the test plug before you plug it into the fuse holder so it shouldn't come up with a fault. It has minimal effect on circuitry.
I have used one without problems and they are widely used on other cars.
Really useful piece of kit.
dave4x4
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The mad hat man wrote:
The procedure is to take the fuse out which is in the circuit you suspect is causing the current drain, stick the fuse into the probe attached to the amp meter then plug the probe back into the fuse holder and read the current.
The procedure is to take the fuse out which is in the circuit you suspect is causing the current drain, stick the fuse into the probe attached to the amp meter then plug the probe back into the fuse holder and read the current.
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No - i asked why yu would want to disconnect the battery with a clamp on ammeter?
dave4x4
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I should have said "or" instead of "and". One or 'tother.
eightinavee
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Things to consider;
1, Current drain on an L322 is 20-30mA,same as a P38.
2,They take 16-18 mins to shut down to sleep,during which time there are several surges as different ECU's do their thing.
3,taking out fuses one by one and replacing them with a plug in will just take forever as plugging the unit in will in most cases wake it all up again.
4,An ordinary current clamp cant measure accurately down low enough,for this kind of measurement you need something like this; K Clamp Series AC/DC, 3.9mm ID, Cat. II 300V - Chauvin Arnoux | Chauvin Arnoux But the only problem,(Besides its cost) is that the clamp will only go around a small wire.I get areound this by using a suitable lead with a croc clip on either end and carefully connecting it into the circuit without losing contact - helps on L322's and is even more help on P38's as you dont have to set windows/sunroof etc.
5, Common drain issues on L322's are the final stage resistor for the fan motors keeping the HEVAC ecu awake,headlight lowering ecu's being full of water,LPG ecu's,old phone kits,dead tracker batteries and water in just about any loom or other ecu.
1, Current drain on an L322 is 20-30mA,same as a P38.
2,They take 16-18 mins to shut down to sleep,during which time there are several surges as different ECU's do their thing.
3,taking out fuses one by one and replacing them with a plug in will just take forever as plugging the unit in will in most cases wake it all up again.
4,An ordinary current clamp cant measure accurately down low enough,for this kind of measurement you need something like this; K Clamp Series AC/DC, 3.9mm ID, Cat. II 300V - Chauvin Arnoux | Chauvin Arnoux But the only problem,(Besides its cost) is that the clamp will only go around a small wire.I get areound this by using a suitable lead with a croc clip on either end and carefully connecting it into the circuit without losing contact - helps on L322's and is even more help on P38's as you dont have to set windows/sunroof etc.
5, Common drain issues on L322's are the final stage resistor for the fan motors keeping the HEVAC ecu awake,headlight lowering ecu's being full of water,LPG ecu's,old phone kits,dead tracker batteries and water in just about any loom or other ecu.
dave4x4
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All good advice. The only other thing I would add is that you can send the BECM to sleep on a p38. There is a procedure for it. You can measure the current draw before and after.
Not sure if you can do this on the L322.
Not sure if you can do this on the L322.
eightinavee
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I have some factory data on P38 BECM's and nowhere does it mention sending one to sleep - only monitoring current draw whilst it goes through its shutdown checks to hopefully get down to 20-30 mA.Cant remember what they are,but its in 3 steps from last activity.
L322 is a nightmare on going to sleep,I stood and watched a scope trace one day all the way through till if slept,after about 16mins.... There is alot going on.
