Battery Woe

[T5Rdragon]

OK, I know the answer to this, in my own mind at least, but it's an odd one, so I thought I'd share:

Recently, my battery has been a bit random; leave the car for a day or 2, and the battery goes flat and the car won't start; sometimes it won't do it etc.

So I was making an appointment with my local VS and I mentioned it; I said that the charge voltage was fine etc, yet it seemed incapable of holding charge. He naturally had a checker that goes beyond my multimeter, so we had a play with that; with the engine running, the device reports good charge and good health. Switch the engine off, and the device still reads good battery health. Which is strange, knowing what I knew.

A drain test shows very little drain with nothing switched off.

But switch on ANY electrical device in the car, and the battery flattens sufficiently to stop the engine turning; I was having the car washed last weekend, and I couldnt start it afterwards; I only had the radio on.

Today, my VS brought my car round to my house after it's service, and he literally pulled up, switched the engine off and had NOTHING on except for the hazards (not the strobes, they've been disconnected to eliminate them as a cause of leak); he was outside for less than 3 minutes before I came out and tried to start the car, and failed. 3 minutes!!!!

So, it seems to me the battery has dead cells, or is otherwise knackered; once started, drive a bit to charge it, and stop again and the starting is strong. But use anything electrical with it off, and it nose dives. Yet it defeated the average battery health checker that mose garages use...

Anyone else disagree that it's the battery, and has another theory to offer? (the altenator is deffo charging fine, and there's no probs when the engine is running).

BTW: Car (and autobox) is running a LOT nicer after it's service, ATF drain/flush/renew and 5 new sparkies - let's hope fuel economy recovers a bit too now ;)

[scott t5]

could be a bad earth???? :nut:

[Engineer]

[QUOTE=T5Rdragon]OK, I know the answer to this, in my own mind at least, but it's an odd one, so I thought I'd share:


I think your proberly right, the only other thing that comes to mind are the 3 one way diodes in the alternator used to prevent battery drain back when the ignition is switched off, if one or more fail its a direct feed back to the stator windings and a flat battery, although I would it expect it to take more than 3 minutes. Put an amp meter in series between either the pos or neg connections on the battery with everything off any major drain will then be apparent.

[twotrees]

OK, I know the answer to this, in my own mind at least, but it's an odd one, so I thought I'd share:

Recently, my battery has been a bit random; leave the car for a day or 2, and the battery goes flat and the car won't start; sometimes it won't do it etc.

So I was making an appointment with my local VS and I mentioned it; I said that the charge voltage was fine etc, yet it seemed incapable of holding charge. He naturally had a checker that goes beyond my multimeter, so we had a play with that; with the engine running, the device reports good charge and good health. Switch the engine off, and the device still reads good battery health. Which is strange, knowing what I knew.

A drain test shows very little drain with nothing switched off.

But switch on ANY electrical device in the car, and the battery flattens sufficiently to stop the engine turning; I was having the car washed last weekend, and I couldnt start it afterwards; I only had the radio on.

Today, my VS brought my car round to my house after it's service, and he literally pulled up, switched the engine off and had NOTHING on except for the hazards (not the strobes, they've been disconnected to eliminate them as a cause of leak); he was outside for less than 3 minutes before I came out and tried to start the car, and failed. 3 minutes!!!!

So, it seems to me the battery has dead cells, or is otherwise knackered; once started, drive a bit to charge it, and stop again and the starting is strong. But use anything electrical with it off, and it nose dives. Yet it defeated the average battery health checker that mose garages use...

Anyone else disagree that it's the battery, and has another theory to offer? (the altenator is deffo charging fine, and there's no probs when the engine is running).

BTW: Car (and autobox) is running a LOT nicer after it's service, ATF drain/flush/renew and 5 new sparkies - let's hope fuel economy recovers a bit too now ;)



THE OLD WAY TO SEE IF YOUER BATTERY IS GOOD IS TO TAKE WIRE OF COIL TURN ENG OVER LOOK INTO CELLS AND IF YOU HAVE BUBBLES YOU NEED NEW BATTERY

[fireclown]

Hi you shouldnt have any discharge really from the battery. i should try a new battery 1st even if u can borrow one for a day just to try it.

[Rufe]

if you would buy one from the dealership (they are pricey but they are heavy duty and generally very good, they retail around £60 or so) then you could have asked them nicely for a borrow of a good one for a day, and if it cured it then you would buy it, if not they could have had it back, and while it was off the car they could have charged it up for you too. obviously depends on how well you know them, or how honest your face is lol, but we do this sometimes at my dealership.

dont forget all genuine volvo battery's have a 3 year warranty on them ok. :)

[twotrees]

OK, I know the answer to this, in my own mind at least, but it's an odd one, so I thought I'd share:

Recently, my battery has been a bit random; leave the car for a day or 2, and the battery goes flat and the car won't start; sometimes it won't do it etc.

So I was making an appointment with my local VS and I mentioned it; I said that the charge voltage was fine etc, yet it seemed incapable of holding charge. He naturally had a checker that goes beyond my multimeter, so we had a play with that; with the engine running, the device reports good charge and good health. Switch the engine off, and the device still reads good battery health. Which is strange, knowing what I knew.

A drain test shows very little drain with nothing switched off.

But switch on ANY electrical device in the car, and the battery flattens sufficiently to stop the engine turning; I was having the car washed last weekend, and I couldnt start it afterwards; I only had the radio on.

Today, my VS brought my car round to my house after it's service, and he literally pulled up, switched the engine off and had NOTHING on except for the hazards (not the strobes, they've been disconnected to eliminate them as a cause of leak); he was outside for less than 3 minutes before I came out and tried to start the car, and failed. 3 minutes!!!!

So, it seems to me the battery has dead cells, or is otherwise knackered; once started, drive a bit to charge it, and stop again and the starting is strong. But use anything electrical with it off, and it nose dives. Yet it defeated the average battery health checker that mose garages use...

Anyone else disagree that it's the battery, and has another theory to offer? (the altenator is deffo charging fine, and there's no probs when the engine is running).

BTW: Car (and autobox) is running a LOT nicer after it's service, ATF drain/flush/renew and 5 new sparkies - let's hope fuel economy recovers a bit too now ;)


Iam almost shore that i gave some other way to see if youer battery was on here so here gose a other one .if you have a charger, drain the battery.by leveing the light on until its dead then charge the battery so that its full

[Wobbly Dave]

Have a spare (good) battery following the demise of my C70.

[NugentS]

Iam almost shore that i gave some other way to see if youer battery was on here so here gose a other one .if you have a charger, drain the battery.by leveing the light on until its dead then charge the battery so that its full

No - No no and a thousand times no.

Car batteries are not designed to be flattened. Its the best way on this planet of killing the battery (other than driving over one in a bulldozer). A single deep discharge on a car battery takes 6 months plus off its life.

A car battery is NOT a leisure battery which can be deep discharged - they are designed for massive drain in short durations and must remain charged.

If the battery has been flattened as many times as the OP has said then its been ruined - irrespective of wether it is the cause of the original fault or not.

By all means try a new battery but do not let it go flat. Make sure with the correct test equipment that its not being drained. Hopefully its the cause of the fault.

Sean