Battery drain electrics problem

Hi any ideas got lovely jag x type got new battery new alternator but something is draining battery I’ve done all checks fuses ect electrician couldn’t find a drain when not in use it will be flat after 24 hours any help would be great

I take it when you say you have checked the fuses, is that by disconnecting the - battery terminal and hooking a DVM into the circuit to determine how much drain there is?

Yes it says there’s no drain by auto electrician

Do the interior lights go off when all the doors are closed?

Is it the factory radio? Does it play when the key is removed?

Yes lights go off now yes factory fitted N yes still plays when key off

The radio could be the problem. A solid 5A draw.

I’d still wanna get a decent 10A meter between the battery and the car to see what the draw is when the car is allegidly closed down for the night.

It should be under 500mA.

Does the car have a cell phone charger added?

No phone charger doesn’t show a drain anywhere but if left for more than 24 hours it’s flat it’s driving me nuts as it’s a lovely car n lovely drive but unless I disconnect the battery at night I can’t use the dam thing

There are exacly 2 possibilities:

  1. There is a drain that your testing proceedures have not discovered yet.

  2. Your new battery is defective.


  1. Requires putting a 10A meter between the battary and the car and seeing how much the car draws when it is shut dowm.

  2. Disconnect the battery from the car and check the battery voltage. Then come back 10-12 hours later and check voltage again. Any noticible self-discharge is a bad battery. Don’t blame the car, get a warrenty replacement on the battery.

Give these a try.

Bought 2 batteries new alternator if I disconnect battery I can connect back up 3 days later and it’s fine .it’s got built in satnav with radio don’t no if that makes a difference

Check to be sure the trunk light is out when the lid is closed. If you aren’t able to actually check it visually, take the bulb out over night. Also check to be sure the glove box light is out.

OK. No question. Your car has a significant load when parked.

Time to connect a ammeter between the battery and the car. You should see over 2A load if the battery is being wiped on an overnight. Start yanking fuses (radio, interior lights to start with) until the meter drops to zero. Then put them back ONE AT A TIME until you see a sharp jump. That will be your culprit.