Thread: Big battery drain

Originally Posted by Aussie Jeepster

Tombie.
If you were to wire up a 12S plug, I'm guessing the (-) from the charger would be pin 3 and the (+) from the charger would be pin 4 - yes? Or would it be pin 2 for the (+)??
Alan

3 & 4

My 2014 Disco, with keyless start, recently had some battery issues that took a while to diagnose. There were some unexpected side effects.

The outcome was the battery needed replacing, even though it charged to a normal voltage, started the engine quite well, and delivered “acceptable” cranking amps according to two tests. The new battery solved all the symptoms which were a constant 1.7 amp drain and “Low Battery, Start engine” messages on the dash.

The episode started with a classic flat battery after 2 days camping. I put that down to frequent opening/closing doors and locking/unlocking and no driving. Jump started it, drove the car to the next town where NRMA roadside assist checked over. Alternator OK, voltage OK, cranking amps down a bit, but the battery just needed a long charge according to the serviceman.

So after a 3 hour drive all seemed well, but suspecting that something may be draining the battery, a clamp meter showed a constant 1.7amp drain on the main battery cables.

Got home and confirmed that “parasitic” drain using a different clamp meter, and charged the battery using a solar regulator with an inline power analyser, which confirmed the battery needed about 40AmpHrs per day to keep up with the 1.7amp discharge. This as consistent with a 90AH battery going flat in 2 days.

During this period the car dash started constantly displaying “Low Battery, Start engine” despite being on the charger, or the car being driven for 40 minute trips or more.

A second battery test by Opposite Lock, who have some familiarity with Discos, advised the cranking amps while just OK, indicate the battery is not probably good enough for the Disco’s electronics. I took the car to a Land Rover service place that had the correct Varta battery in stock. They also tested the old battery and said it was not up to scratch. It was replaced, and the dash message and “parasitic” drain disappeared.

It seems the low battery causes the computer system to not fully go to sleep, causing the abnormal battery drain that ensures the battery does go flat! Subsequent clamp meter checks showed 0.4amp drain with the new battery. That would take 110 days to drain the battery to 50% charge.

So in my experience, if there is any evidence that the battery is low, such as dash messages, low cranking speed or unexplained “Parasitic” loads, get the battery checked, and replace it if the cranking amps are down. Use a genuine LR battery. Mine cost $620 fitted and the computer system reset. Not cheap!

Another revelation from all the monitoring, is that every time the car was unlocked or a door opened, the accessories were activated for 3 minutes before going back to sleep. This and the computer put a 6 amp drain on the battery for that period. I also discovered that the auto electrician that wired the DCDC charger for the auxiliary battery and the relay for the trailer Anderson plug, connected it to “accessory” rather than ignition. So that if the camper trailer was also connected with its DCDC charger, 50 amps could be drawn from the crank battery whenever a car door was opened or the car locked.

I will be getting both changed to only activate when the engine is started.

My message is that if you have an unexplained and seemingly parasitic battery drain, check the battery, and if the cranking amps are down, it may need replacing. The parasitic drain disappeared when the new battery was fitted.

Good one Land Rover! When the battery gets a bit dodgy, make the computer not sleep and ensure the battery goes fully flat in 2 days.

Hi Nmritchie, in this case, the problem was not caused by Land Rover’s electronics, the electronics just made the problem worse.

The “expert” auto electrician’s install was the ultimate cause of the problem.

Having a continual ultra high current load applied to any battery will damage that battery and once the battery is damaged the way yours was, the D4’s electronics was just operating as it would when any failing battery was in use.

The irony is that you never needed the DC/DC device in the first place but that is another story, the point is, your auto electrician had no idea what he was doing in the first place.

You don't need a DC-DC unless the battery is lithium, which require a higher charging profile.
Can your DC-DC deliver 50 amps, as the alternator can?
Get it removed and run a thick cable directly from the alternator to the trailer Anderson plug. That will deliver more power than your DC-DC can put through.
Connect your vehicle second battery through a DBC controller such as a Traxide directly to your starting battery.
Works for me.

Originally Posted by swarover

Hello All,

Have a problem one or some of you may be able to shed some light on. Searching us here and the Disco 3 UK forum, I can't find a similar issue: My 2005 TDV6 D3 has started flattening its battery very quickly while turned off; within a day or so a few days ago, and today six hours after installing recharged battery. Battery is a 20 month old Exide 820CCA as spec for this car.

Problem first noticed on Tuesday morning as a slightly sluggish start, drove 100 km and left the car all day, started again ok (can't recall that start's characteristics) and drove back 100km. Thursday morning (40 hours after switch off Tuesday) no start, dash lights/symbols flashing, voltmeter said 10.34 volts. Removed and charged battery (as advised by battery supplier who I called for advice) until green light on my charger (Waeco Perfect Charge W8) lit as fully charged - where it read 13.69 volts. Friday morning battery siting on bench at 10.79 volts, suspecting battery breakdown, I took it (in a different vehicle) into supplier for them to check and discuss solutions. Supplier charged battery with their machine and load tested it, which it passed no problem. They had been quite prepared to replace it under warranty, but it stacked up. Battery read 12.75 volts after two load tests, and I brought it home.

Installed battery this morning and worked ok, started with normal flourish of a full battery and showed 14.35 volts charging. However, during a 15km drive it did exhibit a slightly sluggish start on the one start in that drive around. Returned home, turned it off and left it for 6 hours (unlocked), tried start again to no avail, battery reads 10.68 volts.

Last weekend I drove the car on some very bad corrugations for about 40km of 100 km of gravel road and track driving, which may have messed something up. BTW the quite wonderful car has done just shy of 440,000 km, so its pretty well run in.

What do you think, a serious drain somewhere, or a crook battery that cheated the load test?

Thanks in anticipation.

Nathan

Hi Nathan,

Had almost the identical experience with my D3. Started with a serious battery drain and ended with a crook battery that cheated the load test.

Installed a new cranking battery. A week or so later, after sitting for about 6 days the battery was so flat that the central locking wouldn’t even work. I measured quite a high parasitic battery drain but neither myself or an auto electrician could track it down. All they could tell me it was something in the vehicle interior. It was intermittent and I ended up leaving the ctek charger on when not in use.

So fast forward about 4 years. Camping on Moreton Island. Fully charged in the evening. Next morning even though the fridge read 12.4 volts and the traxide hadn’t isolated the cranking battery, the engine barely turned over. After failing to start the voltage was about 10.6 volts. Luckily I have solar so all good. Happened two mornings in a row. Took the battery to be tested. All fine. Back in the vehicle fully charged. Flat overnight. New battery, all good.

I now have a bluetooth battery monitor. I have had one incidence of parasitic drain lately but only occurred between when the engine was turned off and started again. Instead of dropping between 0.01 and 0.02 volts per day it dropped by 0.5 volts in 24 hrs. After restarting the vehicle the voltage drop was back to 0.01 volts over the next 24 hrs. Would highly recommend getting a bluetooth battery monitor for the ease of use and history function.

Been away for 2 weeks and battery still at 12.58 volts. Fingers crossed it stays like that.