Battery drain help needed

Mines a 2002 defender 110 td5. battery’s started going flat and happens within 48hrs. put meter across the fuses and found a drain on one circuit. Haven’t narrowed it down yet so pulled the fuse and that seemed to stop the drain. However, the battery’s still going flat and I’m not picking up a drain that I can see. Any ideas where I can look next and where I go from here other than a auto electrician!
Ps. battery still appears to be ok

Disconnect battery for two days and see if it goes flat,the drain you have found may be something that remains live.
If disconnected battery goes flat it is an internal short.

Have you fitted anything in your landy lately,

I once had a starter motor bearing wear, which allowed the starter rotor to short to earth giving symptoms of a dead battery when trying to start.

Possible alternator?
Internal winding fault

tottot said:

Disconnect battery for two days and see if it goes flat,the drain you have found may be something that remains live.
If disconnected battery goes flat it is an internal short.

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I’ll give it a go. Ta

Scooby22 said:

Have you fitted anything in your landy lately,

I once had a starter motor bearing wear, which allowed the starter rotor to short to earth giving symptoms of a dead battery when trying to start.

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Only thing fitted is new light stalk for headlights but was few months ago

Hicap phill said:

Possible alternator?
Internal winding fault

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Alternator is charging but possibly. Is there a way to test for a possible fault or just disconnect it

Just check battery voltage then disconnect alternator for a few hours. Make sure this cable is covered up you don't want a short.

Recheck battery voltage later.
This may help

If the voltage remains OK after leaving the alternator disconnected for a few hours, but when reconnected you see the voltage slowly decrease as it gets depleted, you've isolated the drain as being within the alternator wiring

Do you have an ammeter? If the battery is going flat in 2 days you have something drawing about 1 Amp or 12 Watts. Disconnect positive battery cable and connect through ammeter. See what current is flowing. You can then pull fuses one by one to see if you can stop it.

headintheclouds said:

Do you have an ammeter? If the battery is going flat in 2 days you have something drawing about 1 Amp or 12 Watts. Disconnect positive battery cable and connect through ammeter. See what current is flowing. You can then pull fuses one by one to see if you can stop it.

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Yes that is how I found the original drain. With the fuse pulled it drops to a minimal drain. However the battery’s still going flat and can’t see any other drains from putting amp meter on the other fuses

atromford said:

Yes that is how I found the original drain. With the fuse pulled it drops to a minimal drain. However the battery’s still going flat and can’t see any other drains from putting amp meter on the other fuses

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Both fuseboxes? The one under the drivers seat too. Do you have an aftermarket alarm?

Use the ammeter in line with the battery itself.

Assume battery about 80Ah. It shouldn't drain if left for a month = 720 hours 80/720 = 110mA

Anything above 0.1A = 100mA is too much.

Checked all fuses I know off, including any aftermarket inline ones for kites etc. Has got aftermarket alarm fitted. With the suspect fuse pulled and altanator disconnected I’m still drawing .4 amps but unable to trace where from as pulling fuses 1by1 has no affect

Ok have you now disconnected the battery . Check volts & see if this is the problem ?

Could you have a sticky relay?

Possibly the alarm back up battery is duff and pulling a constant charge current? That fuse will be well hidden for obvious reasons

Batterys got good voltage if left disconnected tho will have to leave it for a period and double check there’s no drop on it. haven’t checked all the relays and will have to strip it down and locate the alarm battery/ fuse

The 400mA drain you measured would probably be enough to cause your trouble, particularly if the battery is getting tired.

Tried everything suggested to best of my ability but no joy . Anyone recommend a good garage/auto electrician north essex area ish?

400mA sounds like it could be an aftermarket stereo or something that has been wired in before the fuse box, might be worth checking out that area behind the radio for some dodgy wiring jobs