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Accord going flat

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boyse7en

New Member
Messages
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Location
Devon
Car
Honda Accord 2.2CDTI
My 2007 Accord Tourer CDTi has a charging issue i can't get to the bottom of.

Battery went flat a couple of times overnight (a few weeks apart), so I checked for a parasitic drain but all seemed well. Then the wife drove to meet a friend, stopped for a couple of minutes and then the car wouldn't start. Jump started it and drove home with every warning light on the dashboard showing on and off.
Took it to a mechanic, who replaced the battery and the alternator.
All has been fine for about two months, and now the same thing has happened - car starts fine, drives 20 miles or so, then battery is flat.
Obviously the battery isn't charging intermittently, but I don't know why. There is talk elsewhere of a faulty ELD module affecting petrol civics and accords (mainly in the USA), but I can't actually find out whether my car even has one.

help or advice appreciated!
 
Very common issue. It’s your Bluetooth module, just locate it and disconnect it. They become faulty and cause a parasitic battery drain.
 
Thanks, but it's not a parasitic drain, as the battery is flat just a minute or two after having been driven 20+ miles.
I guess there is enough juice in it to run the car but not enough left to start it.
 
Sorry I didn’t read your post thoroughly. I would say it’s either battery or alternator again then. These use a smart alternator it’s possible the clutch on it is defective
 
Ok, so I left the car on a charger overnight and the battery was showing 12.7v
Started the car, no problem. No battery or engine light showing when running.
Plugged my basic OBD scanner in and no faults showing. Voltage at the OBD port (which I think is same as at the battery) is showing 12.9-13.5v with engine running.
Putting on the lights doesn't make a difference to the voltage. Lights don't dim at idle. Running it at fast idle doesn't make any difference.

I think 13.3v-ish is too low to charge the battery, but not sure.
 
And now it has been running for 10-15 minutes, if I turn the headlamps off, the voltage drops to just over 12v (12.0 - 12.2v). Turning the lights on puts it back up to 13.3v
 
Should be closer to 14v

Faulty alternator I would say.
 
In case anyone comes across this issue, check the voltage at the battery and then check the voltage from the alternator to earth. They should be pretty much the same (within 0.1/0.2V or so)
Mine were nearly 1V different – 12.9-13.1V at the battery but over 14V at the alternator.
A new cable was fitted and battery is now charging as it should
 
Hello boyse7en,

Having similar issue with my Accord I think. Battery less than a year old, alternator replaced a few years ago, but nothing to suggest that is not working as should. I remember reading somewhere on this forum about the main earth strap from the battery being a possible culprit, which I will look at, as well as your voltage check (thanks for tip) when I have a daylight minute or two. But even after a full battery charge with a conditioner, trying to start car sounds like I have a flat battery, with power draining rapidly and all the dash lights starting to flicker and relays going bonkers. With a jump start, car is fine, no warning lights whilst driving. I’ll try looking at the OBD too. Will also look at the Bluetooth module as F6HAD suggests, as that has not worked for a couple of years anyway. But anyone else got any other suggestions on where to look while I am at it? Will sadly be looking to dispose of car before too long as getting a Civic hatch, but if I can keep the old girl running for just a little longer…
 
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