Battery drain in Landcruiser

pete4130

So my old Landcruiser has decided to start draining the batteries (dual battery set up).

It started just over a week ago and somewhat coincides with me getting a new stereo installed & me replacing the interior light that was blown the past 8 months.

The stereo being the newest thing makes me think it might be that causing it. It was fine for the first few days after bing installed until I accidentally left the interior light on for a few days.

I've since charged the both batteries fully with a charger. One battery is almost brand new and the other is older. I'm not sure of the dual battery system set up but the 2nd battery won't start the motor.

Initially I figured the interior light drained the old battery. Both batteries fully charged and the new battery in as the main battery and working fine. 48 hours later the interior voltmeter tells me the battery has drained a little and not enough juice to start it. This rules out the old battery being the culprit.

I've since popped the interior light bulb out to see if the drain continues. If it does my next step is to pull the fuse on the radio and see if that solves the problem.

I know it could be a whole host of things. The cruiser is 19 years old so there could be wiring that needs repairing anywhere.

Apart from getting a multimeter and checking the voltage when off and pulling each fuse and checking where the drain is coming from is there anything else I could consider doing apart form disconnecting the battery when I'm not driving it?

pete4130

Borrowed a multimeter and voltage is 13.1v and current drain is negligible so I'm at a loss. It's drained both batteries. I've popped the interior bulb out and Ill see if it dies again.

CJhaughey

Batteries are best fitted as pairs, the old one may be dragging the new one down to its level.
Its a sort of self levelling system.
You should check the state of charge of the old battery at the same time as the new one.

pete4130

Thanks CJ.

I've just got the older battery in there for the moment with the interior bulb out. It's strange the multimeter didn't show any drain (0.01).

I just had the new battery in on its own yesterday while the older one was inside charging so it rules out the old battery bringing down the new. The new battery was probably on 9v this morning and only took about 2 hours to come up to fully charged. That sort of rules out that batteries.

As far as I know now, the 2nd battery is isolated from the main battery, so it will get charged but can't get run down from the main. I didn't get a chance to switch the batteries around initially to see if the 2nd battery was good at the time. I just assumed it was flat.

I guess I'm on the slow process of elimination to find out whats causing it. Next step pop out the radio fuse and see what happens. Just a pain not being confident to drive it anywhere right now.

Now I've got the multimeter I can check it in the morning to see if it's dropped again.

CJhaughey

Which model is it? a 70 series?

pete4130

Yeah, an old 75 series. Bar the electrical gremlins I've had lately its running great. Slowly getting it ready for a 9-12 month trip around Australia with the missus.

dusktodawn

pete4130 wrote: »

Thanks CJ.

The new battery was probably on 9v this morning and only took about 2 hours to come up to fully charged. That sort of rules out that batteries.

High voltage doesn't mean enough power, seems to me like this battery is useless

dusktodawn

had a similar problem after installing a new radio, found out that even when radio was turned off it still took a good bit of battery power.
Installed an additional switch to cut off all power for the radio, problem solved

cletus

Depending on the stereo and the installation, it may not be turning itself off automatically when you turn off the ignition. My wife has to manually turn off the radio before she cuts the engine

pete4130

It isn't just the old battery. The new battery (3 months old) got drained too. I've my suspicion its the stereo, which does seem to turn itself off. For both a new and old battery to drain in 48 hours means I've got a parasitic drain somewhere even though my multimeter isn't reading a big draw from the battery. It could be some loose wiring somewhere. If the drain stops after I pull the fuse for the stereo then I know there is a problem with the wiring job when it was installed.

ballooba

I'm experiencing a similar issue in my 90 series. New battery in it but keeps draining. Nothing changed with regard to stereo or other electrics.

pete4130

ballooba wrote: »

I'm experiencing a similar issue in my 90 series. New battery in it but keeps draining. Nothing changed with regard to stereo or other electrics.

Get the cheap multimeter and start pulling fuses!

ballooba

pete4130 wrote: »

Get the cheap multimeter and start pulling fuses!

Yeah, might be a job for the weekend, thanks. Can this be caused by a short either? i.e. if some rubber conduits or cable perished. I must check that the battery is the correct spec too. Father has custody of it at the moment due to my lack of available parking.

mullingar

Disconnect a battery terminal so you can measure the discharge current properly via the current settings with a multimeter, making sure all lights/radio/etc is off, and repeat for the other battery.

Once you confirmed the problem is some circuit discharging the battery, rather than the battery self-discharging, disconnect that radio, check the current reading, if it still registers a power drain, start pulling every fuse, one-by-one, until the multimeter reports a full drop in discharge current.

CJhaughey

pete4130 wrote: »

As far as I know now, the 2nd battery is isolated from the main battery, so it will get charged but can't get run down from the main. I didn't get a chance to switch the batteries around initially to see if the 2nd battery was good at the time. I just assumed it was flat.

Most factory dual battery setups run in parallel and don't have an auto isolating switch, I don't know how yours is rigged though.
You can work through the fuse board fuse by fuse to see where the power is running through when the engine is off.
This is time consuming but will show if there is any current running through a particular circuit.
If it doesn't show in the fuseboard it will be in the wiring on the engine side. Battery/alternator/earth.

pete4130

It's not a factory set up. I'm here in Aus and the 75 is set up as a camper with a fridge, outlet sockets etc... so I think the 2nd battery is rigged for running all the camping gear and is isolated from the main battery. At this stage I'm doubting if the dual system is even working properly. Theres a trip to the auto electrician due anyway to get a kill switch installed and check the condition of the current wiring.

The battery issue has me dumbfounded. No drain on the battery but they are losing charge. I just want to know whats causing it to get it sorted at this stage.