Renault Laguna Mk1 new battery gone flat.

[Mark]

Hi all

When my Dad passed away 15 years ago my mum wanted to keep his car and as she doesn't drive it's registered in my name and I use it to take her to Doctors etc. 

Battery was quite old but always span the car over and starts first time. The other day I went to take her to an appointment and I couldn't open the car with the central locking. Turned out the battery was dead flat. Replace a few days ago, drove the car a few miles to Sainsbury's and back and left the car. Gone to start the car this morning, same problem battery dead flat. Terminals are cold, and unlikely to be a faulty new battery (Halfords).

So not sure where to start. Got the old battery fully charged, new one on charge. I was going to fit a battery, but not sure how to check if it's discharging and then how to track down the culprit.

Any advice appreciated. 

[Nick Jones]

Usual suspects are boot light staying on, glove box light staying on or occasionally strange happenings with wiper self-park circuits (dunno if this is a thing with Renaults).

Alarms, immobilisers and stereos can also sometimes cause problems, aftermarket ones especially.

If nothing obvious you can try connecting a multimeter in ammeter mode (most will do up to 10A) in series with the battery and see what the resting draw is. Should be a few 10s of mA at most. Less the better. If more, start pulling fuses. Be aware that some electronics systems may take a while to go to sleep - though the car may well be old enough for that not to be an issue.

[mossmonaco]

Are you sure that the charging circuit is working? check the battery voltage with/without the engine running while the headlights are on (ideally after driving a few miles).

 

[Mark]

Thanks for the advice.

The new battery has only done a few miles and was fully charged when fitted. I will check that the alternator is charging though, incase there is short inside that is draining the battery.

Dusted off my old multimeter, maybe used it a few times in 30 years, looks new but the LCD read out was all over the place, in any mode, connected or not, so gave up and bought a new one tonight. I'll have a go tomorrow once i work out how to use the multimeter.

I've had problems with the central locking for the past couple of years, not unlocking/locking so first thoughts is it could be a faulty solenoid. 

It's a 1996, Laguna 1.8 sport, so not a great deal of electronics. Apparently Mk1 Lagunas are at the top of the list as being nearly extinct. When was the last time your saw a mk1?  Going the same way as mk3 Cortina, Sierra etc. This would have gone years ago left to me, it was only my mum's attachment that has saved it so far. 

Supprisingly some parts are getting near impossible to find. Got lucky last year and found a couple of nos headlights.

Hopefully what ever the cause can be replace, otherwise it could be the end of the road.

The central locking has a cut out incorporated. Before turning the ignition you have to lock and unlock the doors, otherwise the engine runs for a second and dies, so hope it's not a central locking fault.

 

Edited March 16, 2021 by Mark