Battery drain and dead electrics

[Yog Sothoth]

I was having battery problems with my '97 V70R and the indicators were that the battery, which was several years old, probably needed replacing. It had got to the point where it would need jump starting after only a few days stood in the cold weather.
It was a Halfords 096 Calcium battery so I replaced it like for like. Not cheap at £130 fitted! That was 2 weeks ago. It started beautifully and I thought it was problem solved. I last drove it on Friday (17th Dec).
Went to start it on Tuesday (21st) and didn't even get that far! The doors wouldn't unlock! Bad sign.
I managed to get in via the tailgate, which is the only door that works with a key.
The dash LCD display was kind of blank although all the black LCD characters were sort of flickering on then fading away intermittently. No red blinking alarm light on the dash. The only solid thing was the red blinking LED on the stereo unit.
Tried the ignition; not even a click.
Popped the bonnet and connected a jump starter pack. It beeped that the battery was too discharged to jump start. Oh dear.
Got out the CTEK smart charger and hooked it up, in hope more than expectation. It showed the >8hr (to charge) light, although it was blinking in a strange pattern rather than steady (I wondered if that was some sort of code but can't find anything online).
Anyway, 36 hours later, nothing has changed. The new battery seems to be buggered, won't take any charge, and the car electrics are effectively dead.
Looks like another new battery. This time I might just try a cheaper one off ebay (same ratings) and fit it myself. I was worried about disconnecting the battery before but that's effectively what the situation is now anyway, so not much to lose.
Behind all this crap, which I really don't need two days before christmas, I still don't know what was draining the battery! I guess at least if I can get a good battery back in, I can take it to the local garage to have a look at, assuming the loss of battery power hasn't made it undriveable.
The battery drain started in the summer, for no obvious reason. It's got worse though, probably due to the falling temperatures. I just thought it was the battery itself, and not too big a deal as long as I kept it charged.
There was an interior rear light set to 'on' which I spotted yesterday but they all go out when I lock the car, so can't see it being that.
The lambda light came on recently and I hadn't got to the bottom of why. It went off after the new battery was fitted but then came back on the day after, so maybe that's a hint?
The ABS and TRAC lights were also on; I'd had my ABS unit resoldered at the start of the year which worked but the lights reappeared after a few months. Maybe that is connected to the battery drain, I don't know.
What a nightmare.

[Luxobarge]

OK, a number of points to make here:

1) I've had terrible experiences with Halfords batteries, if may well be a faulty battery. Hopefully you can get your money back, if replacing it I'd strongly recommend getting one online from Tayna batteries, I've always had very good service from them, very good pricing, fast delivery and a choice of battery quality - I'd recommend going for the best quality you can, which is not necessarily the highest capacity. High capacity batteries achieve this through having thinner plates, which can degrade and fall apart quicker, I usually go for a medium-capacity battery from a decent manufacturer such as Yuasa, Bosch etc., which will be more than enough to run your car. Also, steer clear of "Lion" batteries, I found they last maybe 18 months, often less. A bit of time on Google will steer you towards which manufacturers are best and which to avoid.

2) You probably have a parasitic drain somewhere, a common culprit is the glove box light staying on, or dodgy microswitches in the doors leaving the puddle lights on, or some other light. You may find it by experimentation, but a good technique (once you have a decent battery in the car) is to open the bonnet, shut and lock everything else and measure the static current draw from the battery with a multimeter. It should be just a few milliamps, say 0.03 amps or something of that order. This is the kind of current drawn by the alarm, clock etc. Anything more and you have a problem. To find the problem start pulling fuses until the current draw goes away, the fuse that cures it will tell you the circuit that is drawing the current and you can investigate deeper into that.

3) I'd get this problem solved before worrying about EML and ABS lights, on mine I've sometimes found weird faults caused simply by low battery voltage, once you've got a decent battery voltage present ALL the time (i.e. over 12V even with everything stopped) then see if you have any fault lights that consistently come on. Remember that if you have an ABS light, the car will need to travel at over 15 mph with no faults present before the light will go off.

So basically it looks to me like you have two faults, one is a crap Halfords battery and the other is a parasitic current drain somewhere in the car. Neither is normally a major pain to solve, but you have my sympathy for this problem occurring right at this time of year! Hope this has helped, all the best.

[RollingThunder]

Hi mate, firstly sorry to hear about your woes - you could do without it just before Christmas!

The various warning lamps will be due to the low battery - its normal for you to get the Christmas tree dash when the battery voltage gets very low.

More good news - your new battery won't be scrap. The issue is that its voltage has dropped below the level that the CTEK charger can cope with. I also had a CTEK charger and did exactly what you have done - replace a perfectly good, but discharged battery because the CTEK unit said it was faulty. I was tipped off by a friend who had the same issue and bought a NOCO G3500 battery charger. These can cope with totally discharged batteries and recovers them very nicely. (They are expensive now - I bought mine during an Amazon sale).

So getting/borrowing a NOCO charger will solve your battery replacement issue - it'll be around the same price as a new battery, but you'll be able to recover batteries in the future. If you still have your old battery, get the NOCO charger to recover that, then leave it on a standby charge in the garage - thats what I do, so if I do get a battery issue I can just swap them over.

Which leaves the battery drain problem. You'll need a multimeter, set to amps. First thing is to tape down the alarm bonnet switch so that the alarm thinks the bonnet is shut. Then close all the doors and lock the car with the key, and leave the car for 10 mins to allow the alarm to go into sleep mode. Obviously you'll need a fully charged battery before you do this

Check the current going across the battery - the usually agreed normal is around 30-50 mAmps. This drain is due to the alarm, the radio memory etc. As your battery is draining so quickly, I'm sure it will be higher than this

Next record the current across each fuse in the fusebox, noting the fuse number and current. Note the circuit that each fuse with a higher-than-the-others reading is protecting - that should give you a few circuits to check. The usual one is interior lighting, but anything is possible if a cable has become chafed.

Let us know how you get on, or if you need any further help

Good luck!

edit - Luxobarge beat me to it lol. At least we have the same ideas

[volvo again]

As already mentioned, one of the common reasons is the door marker lights staying on when doors closed, due to faulty microswitched in the lock assembly.
Dificult to see when the doors are closed but try looking inside when it's dark, I found you could see a red glow from the light if it's on.

[Yog Sothoth]

Cheers guys. That's cheered me up a bit!
The CTEK charger has a 'RECON' mode, supposedly for discharged batteries, which hasn't worked here. But I note that the Noco chargers explicitly state they can force charge a battery even from 1V, which is amazing. Not as expensive as I thought either. There's also a brand called TopDon which are cheaper than the Noco but claim to do the same force charging from <1V.
Incidentally I put a meter across the battery and it's less than 4V!

[Yog Sothoth]

Originally Posted by RollingThunder

First thing is to tape down the alarm bonnet switch so that the alarm thinks the bonnet is shut. Then close all the doors and lock the car with the key, same ideas

Just had a quick look for the bonnet sensor and couldn't find it. Is it part of the bonnet lock?

The other issue is I have only one key and fob. The key won't lock/unlock any door other than the tailgate, so I depend on the fob, and even that only works if I hold it close to the windscreen, even with a new battery in it.

So if I tape down the bonnet sensor, then lock the car with the fob, that should be OK? If not, it'll amuse the neighbours at least.

[volvo again]

I think the alarm switch is indeed part of the bonnet lock, you should see two wires and a plug on the n/s latch.

On a different note, I sent my fob away to be repaired, posted 1st class on Monday came back Wednesday, but now works fine. Apparently press button micro switched fail, these are replaced, new battery & case.

https://www.ebay.co.uk/itm/330477323723

[rudi dudi]

@ Yog
You don't need anything fancy to force charge any battery.
Either use an old school dumb manual battery charger that just does what it told.
Or connect to a charged battery via jump leads.
Simples.

[CNGBiFuel]

I've seen this a few times over the years, causes in my case:

1) Iffy door-latch micro-switches x 1
2) Tired alternators x 3

I don't ever seem to get more than 3-4 years out of a battery, hence I buy Yuasa via Halfrods. Yes, easily dearest way to buy batteries, but they honour their warranty, thus, if you follow my 'not-if-but-when-it fails' logic, a 5 year Yuasa soon becomes a 8-10 year one.

When you 'drive' old sheds in excess of standard 'big whoopsie' miles, at some point you'll see an alternator etc go down. It's guaranteed, you just will. Not if - you will.

With 'one too many' deep-cycle discharges killing even the best of batteries, this trick works. And is long-game cheapest and best. Yes you can source a battery for £60, only don't. They won't collect the old one, hence you've £20 courier bill for the seller to then say "it's not a manufacturing fault".... there IS no 'in-practice' warranty. Unless you're set to scrap inside the year, why would you want a cheapo battery?


Don't forget though, Halfrods are banking on not needing to honour their sale... you being the average instant-gratification idiot... ie: they can look you dead in the eye - and tacitly regard you as a moron - 95% of you won't have your 4-5 YO receipt, or won't have the car by then..... keep your receipt. It's worth a NEW battery.

[acshortt5]

Usually for me batteries fail just beyond the warranty... In the case of the mx5 it was a week after the 4 year guarantee ran out!

My local Halfords always ask for an email address to send receipts (been doing it for about a year) which is handy for the expensive stuff but if I'm just getting shop towel etc I just get the paper copy... Which as you suggest either gets misplaced or the ink disappears off it.