NewHilux.net

Hi All - I thought I had this problem licked last year.
When my 2007 Hilux dual cab auto diesel is left sitting for 5 days, the battery is flat (actually not quite as I have a low voltage cut out fitted, it cuts in). I have had an auto electrician come and have a look and he could not isolate the intermittent problem. Looking at other posts last year I bit the bullet and replaced the alternator with 100Amp. Same again. The battery is also a new one (supplier replaced when first new one kept going flat even though it was testing ok).
Temporarily disconnected remote locking system (also domelight, radio, clock etc that feed from this) - lasted an extra day.
I have booked it in to another auto electrician for a few days to see what he can find. Problem started about 18 months ago and did not immediately follow any additional new electrical equipment but it just may be that it never sat idle for that long before.
Anyone got any suggestions?

Don't know much about electrics mate but my nearly 1 year old SR5 TD sits for 42 days without cranking while I'm at work. Has done since I bought it June last year and starts no problems at all when I get home for my 18 days off. Sounds like there is something draining the battery while the vehicle is off.

Definitely something amiss but what?? Have heard of similar on Landcruiser V8 Petrol, and others where diode on alternator was problem but can't find this cause yet.

I have an 08 that does the same thing ill be watching this thread to see what you find

I'd just use a multimeter to check the current draw with everything off, then start pulling fuses one at a time to try and narrow it down.

have you done a load test on the battery? good chance it's rooted mate. auto sparky should have tested for that.

I leave mine for weeks with no issue... then again I have volt meters on my dash for both batteries, and can see any issues ahead of time ... usually my auxillary is the one which cops it, due to leaving a fridge on etc.

You mention that you have a low voltage isolator fitted. Do you mean it's wired up to isolates a 2nd battery from the starter battery or completely isolates the starter battery when the voltage drops?
Either way, you may find that it's the isolator itself that is draining the battery. Depending on what type it is it will draw a different amount, but they all draw some current when on standby.

Thanks all for the suggestions but this is what we have done in the past:
Fitted the low voltage isolator to the start battery BECAUSE it was flat after 5 days
Removed every fuse from every fused circuit and still on and off current draw still occurring and fluctuating
original battery replaced and it recurred again. Auto electrician convinced battery supplier to replace with new battery which they did and... yep same again flat after 6 days following a 250km trip still flat
Replaced alternator - same again!!!
Disconnected the remote system and still flat after days.
MOST frustrating

So you can see the current draw occasionally?

Deffinately something drawing some voltage, assuming youve been taking the fuses out from the cabin fuse box - have you tried removing the bigger fuses in the engine bay one at a time and tested amp draw before and after?

After the battery goes flat and you jump start the vehicle, is the alternator able to recharge the battery?

Found the problem in my 09 was a cheap head unit that was installed prior to me buying the Hilux. The unit was drawing much too much current from the battery with everything off, around 200 ma. Pulled every fuse and could not find the problem. Finally took the head unit out and put in a new one and problem was solved. Turning the radio off and ign off would not disconnect the old radio, still pulls current to keep the internal settings alive.

From what I'm reading of the checks you've done the next step would be to start checking earths. Not just the battery all of them. If you see an earth point on the engine or body undo it, clean it and resecure.

Not been here for a while - down the coast. However we have removed fuses from both vehicle compartment and the engine bay, the new alternator (or even a solar panel) can charge up the newish battery ok - we don't need to jump start as I can override the low voltage isolator.
With the current draw fluctuating it is hard to locate as well. Will post here again after next Friday whether the alternative auto electrician find something or not so everyone is in the loop.

commenting on this for future posts. I have the same problem in my 08 hilux. I went away for 10 days and came back, the battery was dead flat. Wouldn't even make a clicking noise. Anyway, after trying several times to jump start it, we eventually got it going by towing it and starting it (grandad though he was pretty smart because his patrol got it going..).

I gave it to my mechanic and he tested it and said that it was probably due to the security system installed in the car and that it would have a slight drain (even though 10 days still seemed ridiculously short). He said he was confident that there wasn't anything wrong with the battery.

Anyway, problem is,this morning the battery was flat again. I have been driving it every day for the last week so no security system could drain a battery that fast. I have a stock hilux (hopefully not for too much longer) so there are no major accessories draining power from the battery.

Anyone have any ideas? I've thought about changing the battery, alternator or even starter motor but I don't wanna go throwing money at a car if its not going to fix the problem.

cheers

just my 2 cents, but you asking for suggestion. had issue on my old 100series, firstt time it was left for 4 days without starting, battery flat...keeping it short, I found the relay for the spotlights that were on the car when I got it were back the front, relay was always engaged but light not on.

Get a multi meter and check draw levels at the battery, plenty videos on YouTube that shown you how to do it. If thats ok get your battery tested. It could be stuffed. Batteries really only reliable for 3 years these days.