Battery discharge

[GTIAlex]

Having trouble with the battery discharging

For example. Battery showing 7volts when the negative is not connected (i know this is too low). As soon as you connect the negative the battery shows 0 volts

Disconnect negative again and back to 7.


Jump the van and runs fine as soon as you take the jump pack off, the van cuts out.

Any ideas?

[finlo]

The battery is flat and the van is probably not charging.

[GTIAlex]

charged the battery and it shows 12v.
Battery fully charged

As soon as you connect the negative terminal, the battery shows 0v.

[TooMany2cvs]

GTIAlex said:

Having trouble with the battery discharging

For example. Battery showing 7volts when the negative is not connected (i know this is too low). As soon as you connect the negative the battery shows 0 volts

Disconnect negative again and back to 7.

Jump the van and runs fine as soon as you take the jump pack off, the van cuts out.

Any ideas?

When you reconnect it, something electrical in the van is trying to power up - stereo, alarm, ECU, memory, interior light... It's taking more current than the utterly shagged and monumentally flat battery can deliver, so it just flatlines.

[GTIAlex]

TooMany2cvs said:

GTIAlex said:

Having trouble with the battery discharging

For example. Battery showing 7volts when the negative is not connected (i know this is too low). As soon as you connect the negative the battery shows 0 volts

Disconnect negative again and back to 7.

Jump the van and runs fine as soon as you take the jump pack off, the van cuts out.

Any ideas?

When you reconnect it, something electrical in the van is trying to power up - stereo, alarm, ECU, memory, interior light... It's taking more current than the utterly shagged and monumentally flat battery can deliver, so it just flatlines.

Yeah I get that but how can the battery be described as shagged and momunmentally flat when its sat in my garage for a month at almost 13v no problem and been on a trickle charger.

Van has no radio, no ecu and no interior lights or no alarm.

Nothing in the van would draw that much power in seconds. This is different to a parasitic drain.

[GTIAlex]

The battery is about 2 months old and has done zero miles and never been flat.

[GreenV8S]

GTIAlex said:

Yeah I get that but how can the battery be described as shagged

How can you describe it as anything else when the voltage drops massively under a slight load despite apparently being fully charged?

[GreenV8S]

GTIAlex said:

The battery is about 2 months old and has done zero miles and never been flat.

If it was showing 7V then it was not only flat, but discharged so far that battery damage was almost inevitable.

[GTIAlex]

GreenV8S said:

GTIAlex said:

Yeah I get that but how can the battery be described as shagged

How can you describe it as anything else when the voltage drops massively under a slight load despite apparently being fully charged?

So we saying that a new battery would solve the problem?

[TooMany2cvs]

GTIAlex said:

...how can the battery be described as shagged and momunmentally flat when its sat in my garage for a month at almost 13v no problem and been on a trickle charger.

So, umm, how come it's 7v when there's nothing connected?

[GTIAlex]

TooMany2cvs said:

GTIAlex said:

...how can the battery be described as shagged and momunmentally flat when its sat in my garage for a month at almost 13v no problem and been on a trickle charger.

So, umm, how come it's 7v when there's nothing connected?

Because obviously it had lost some while ive been diagnosing.

never been flat...until now, I should of said.

[PositronicRay]

GTIAlex said:

GreenV8S said:

GTIAlex said:

Yeah I get that but how can the battery be described as shagged

How can you describe it as anything else when the voltage drops massively under a slight load despite apparently being fully charged?

So we saying that a new battery would solve the problem?

If the battery is only 2 months old warranty.

[GTIAlex]

PositronicRay said:

GTIAlex said:

GreenV8S said:

GTIAlex said:

Yeah I get that but how can the battery be described as shagged

How can you describe it as anything else when the voltage drops massively under a slight load despite apparently being fully charged?

So we saying that a new battery would solve the problem?

If the battery is only 2 months old warranty.

Are the problems I am describing indicating the it is definitely the battery at fault?

[GreenV8S]

GTIAlex said:

Are the problems I am describing indicating the it is definitely the battery at fault?

If the battery shows as fully charged but won't hold voltage under even a light load then it is knackered. That might be a manufacturing fault but might equally be the result of something you've done to it.

Can you confirm your voltage measurements are being taken at the battery terminals?

[GTIAlex]

GreenV8S said:

If the battery shows as fully charged but won't hold voltage under even a light load then it is knackered. That might be a manufacturing fault but might equally be the result of something you've done to it.

Can you confirm your voltage measurements are being taken at the battery terminals?

Yeah battery terminals.

Il get the battery swapped tomorrow and see.

[TooMany2cvs]

GTIAlex said:

TooMany2cvs said:

GTIAlex said:

...how can the battery be described as shagged and momunmentally flat when its sat in my garage for a month at almost 13v no problem and been on a trickle charger.

So, umm, how come it's 7v when there's nothing connected?

Because obviously it had lost some while ive been diagnosing.

never been flat...until now, I should of said.

SEVEN volts, did you say...?

[GTIAlex]

yeah I get your point.


UPDATE.


New battery today, brand new..new. Its new...Fully charged.


Less dramatic symptoms however, put the meter between the lead and the neg terminal and measured the draw and its showing at 2amps.

Pulled each fuse one by one and no changes. Got to go round and check all the earth points tomorrow.

Been going through all the wiring from the alternator to the battery so its all starting to look a lot healthier just need to fine the source of the drain.

[bearman68]

Pulling the fuses out and showing no difference on the drain is PROBABLY the alternator. Dis the alternator, and check the drain then - that might be why the battery was dead in the first place. HTH.

[GTIAlex]

bearman68 said:

Pulling the fuses out and showing no difference on the drain is PROBABLY the alternator. Dis the alternator, and check the drain then - that might be why the battery was dead in the first place. HTH.

Alternator is new and charges at 14v.

[GreenV8S]

GTIAlex said:

Alternator is new and charges at 14v.

New doesn't mean it can't be faulty. Does the drain stop when you disconnect the alternator?