Flat battery AGAIN!

[DomP182]

Right, I thought I'd solved this by fitting a new alternator but still my battery is draining after a few weeks left with out use.

Please can someone give me some advice on what to look for, truley fed up now.

 

[Ben]

What’s the battery health like?

 

[DomP182]

It was new 2 years ago, Bosch s4

 

[DomP182]

There must be something draining somewhere but drain tests have shown only a tiny mah draw

 

[Darren61]

Get yourself a battery conditoner/charger if you’re leaving it standing for weeks at a time

 

[MLB]

A few weeks isn't really bad though with alarm etc on? How much is the mah draw?

And 44ah isn't huge really for the standard size S4 or have you got a bigger size battery?

Maybe get a ctek charger or similar or disconnect the battery when you expect not to use it for a while?

 

[DomP182]

I have wondered this, any recommendations.?

 

[Darren61]

I have wondered this, any recommendations.?

CTEK MXS 5.0 and buy the comfort connect so you can literally lift the bonnet and plug it into the mains.

Can’t believe I didn’t buy one years ago!

 

[DomP182]

CTEK MXS 5.0 and buy the comfort connect so you can literally lift the bonnet and plug it into the mains.

Can’t believe I didn’t buy one years ago!

Thanks @Darren61 , I've got a ctek for my motorbike but I leave that 6 months without use, surely I shouldn't be having problems after 2-3 weeks. One for the Christmas list!

 

[Darren61]

 

[Darren61]

Thanks @Darren61 , I've got a ctek for my motorbike but I leave that 6 months without use, surely I shouldn't be having problems after 2-3 weeks. One for the Christmas list!

I agree but I was having the same issue with my car (it is a track car so doesn’t get daily use) but I have the same battery as you and even had that replaced by ECP thinking that I had a dud. I had a new starter motor, new alternator. New Earth strap, everthing checked and it would t start after the same period of time being stood.

Ever since getting the CTEK it’s started every time with no issue.

 

[Kev@KAM]

I leave mine plugged in to a CTEK charger. Unless the alarm is deactivated there will always be a drain

 

[DomP182]

I leave mine plugged in to a CTEK charger. Unless the alarm is deactivated there will always be a drain

Only problem is it's not near to a mains socket, probably 5-6 metres away. I still want to know what's draining it

 

[Darren61]

Mine’s about 5 metres from the socket in the garage. They sell an extension cable.

If you’re not using it for 3/4 weeks at a time, in current weather conditions (assuming it’s in a cold garage?) then I think you’re wasting your time chasing the drain.

Based on your usage a trickle charger/conditioner just makes since considering the small cost...

 

[npt]

It should be fine for 4 weeks, you'd need to go through the fuse box and see what's taking power and to check the alternator is producing the voltage it should be, obvious places to start are boot/glove box lights staying on etc

 

[DomP182]

It should be fine for 4 weeks, you'd need to go through the fuse box and see what's taking power and to check the alternator is producing the voltage it should be, obvious places to start are boot/glove box lights staying on etc

I'm at a loss mate, I got the drain down to about 10milliamps with a bosch s4 battery that was new two years ago.

My car is outside so I'd need to trail a lead to it which in winter isnt going to be a great idea.

 

[Ben]

Could you put a battery isolator on to quickly disconnect the battery when the car isn’t in use?

 

[DomP182]

Could you put a battery isolator on to quickly disconnect the battery when the car isn’t in use?

Yeah that's an option, annoying to lose the keycode everytime but it would save the battery

 

[npt]

I'm at a loss mate, I got the drain down to about 10milliamps with a bosch s4 battery that was new two years ago.

My car is outside so I'd need to trail a lead to it which in winter isnt going to be a great idea.

Like I said best to find the drain, power must be getting sucked from the battery through one of the fuses, it takes time but should eventually find it, get battery checked also as it may have a weak cell which will hold enough power to start the car in the short term but not enough power over 3wks or so, again this is a common issue when batterys start to fail and symptoms are like what your experiencing so I'd start there, electric/power issues are a pain

 

[JamesBryan]

Are you sure it's a 10 milliamp draw and not 100?

10mah or 0.01a should in theory last 4400 hours or 183 days.

100mah or 0.1a would be 18 days, which is roughly what you're seeing....

 

[DomP182]

Are you sure it's a 10 milliamp draw and not 100?

10mah or 0.01a should in theory last 4400 hours or 183 days.

100mah or 0.1a would be 18 days, which is roughly what you're seeing....

Pretty sure but I'm going to go through it all again this weekend if its dry

 

[JamesBryan]

Pretty sure but I'm going to go through it all again this weekend if its dry

Failing that it might just need a good cycle on a charger. Those Ctek ones have a repair function I believe, be worth running that on it.

If it's 2 years old and been drained a few times it might not be 100% health.

 

[DomP182]

Well it might have a battery issue but it just sailed through its MOT

 

[MLB]

Nice!

I've just measured both my Clio's.

The Arctic draws about 10 milliamps and lasts practically indefinitely on a standard battery while the Petrol Blue draws about 70 milliamps and used to drain its race battery in about eight to ten days which seems about right.

Were they able to check your battery health while it was in for the MOT?

 

[DomP182]

Good point!

 

[Not a Diesel!!!]

Got a ctek.

God send especially with covid.

Cycle to work in the week. Cars used to have a good run at weekend. Now that's not happening just pop on charger once a fortnight.

The one outside garage i just check there is no rain forecast.

 

[Not a Diesel!!!]

It's too late once you start having problems. May have knackered the battery.

 

[Walnut3]

Got a ctek.

God send especially with covid.

Cycle to work in the week. Cars used to have a good run at weekend. Now that's not happening just pop on charger once a fortnight.

The one outside garage i just check there is no rain forecast.

The Ctek extension lead has been fine out in the rain, mine's outside and permanently plugged in.

 

[Darren S]

I personally wouldn't be bothered about a few weeks between starts - unless the car was parked several miles from my house.

When I had the Evo, I was pushing it with three days if I didn't start it and that was a bind - especially when parked on the driveway in the cold. I think the worst I had was barely two days between starts and it just caught when I span it over. Once it started, it was fine.

Iirc, the default battery was the same size used on the Nissan Micra - which is crazy for a car of that size. Made worse by the fact that I had an aftermarket alarm on there and a rehashed headlight setup with ignitors, ballasts and wiring that appeared to have been done by Stevie Wonder after a weekend sesh.

Could be worse, I guess. On the Lotus 340R, if the battery went flat, then entire body shell had to be lifted up and off to access it. Why an access hatch wasn't put into the design from the get-go is anyone's guess!

 

[Not a Diesel!!!]

The other thing I am conscious at this time of year & with COVID.

Don't use all week.
Drive to supermarket with lights, heater, rear heater, stereo. 2 miles
Drive to petrol station 0.5 mile.
Drive Home 2 miles.

3 Starts .... 4.5 miles.

So the times I am driving are not enough to put meaningful charge back in the battery.

Once charged the stop/start works for a few days ( this used to be the same on my E92 M3)

A mate of mine just put a new battery in his 3 year old golf R. Got a dealer contribution but still paid £150. In April I told him to get a CTEK. My neighbour has had RAC up twice in last 6 months to her under year old 4x4. First time mid lockdown they told her to take it for a 40 minute drive once a week. People are just not doing the miles at the moment.

 

[MLB]

And those 4.5 miles are probably start stop traffic where the alternator hardly has any output (only 26 amps at 1500rpm).

Needs to be a proper motorway drive keeping it at 2500/3000 rpm for those 40 minutes.

 

[Darren S]

And those 4.5 miles are probably start stop traffic where the alternator hardly has any output (only 26 amps at 1500rpm).

Needs to be a proper motorway drive keeping it at 2500/3000 rpm for those 40 minutes.

I'm still working from home and the mileage is way down compared to the normal, non-COVID situation.

However, my wife nabs the keys at least once a week and her journey is 15 miles each way with a nice mixture of A-road and motorway. Should help keep the battery going, hopefully!

 

[Rod B]

Once had a similar battery problem with a Daimler I had. Local electrical specialist could not see any problem with any of the electrics, but one of electricians asked if the heated rear window was left on. It was. I turned it off. Problem solved !

 

[MLB]

I'm just thinking out loud here, but how are the contacts in your rear lights @DomP182?

Maybe some corrosion slowly draining your battery?

 

[DomP182]

Possible I suppose @MLB I've had them off in the last year but I'll certainly double check. To rough here today to have the bonnet open checking with a multimeter, hopefully tomorrow

 

[MLB]

Good luck! Hope you get it sorted, I hate electrical stuff, much rather have a couple of rusty bolts..

 

[RustyMojo]

Dom, do you run standard interior light bulbs or have you switch to led? I just changed mine to Led and noticed that even when off I could see what I though was a reflection from the bulb. I then disconnected the battery as I finished messing around with the car and checked. It appears the bulb was slightly lit... cheap eBay tat. I’m not even sure how that happens if the switch is off and the doors closed? It was so dim you wouldn’t see it if the car was outside.

 

[DomP182]

Dom, do you run standard interior light bulbs or have you switch to led? I just changed mine to Led and noticed that even when off I could see what I though was a reflection from the bulb. I then disconnected the battery as I finished messing around with the car and checked. It appears the bulb was slightly lit... cheap eBay tat. I’m not even sure how that happens if the switch is off and the doors closed? It was so dim you wouldn’t see it if the car was outside.

I do indeed Russ and I've noticed the dim glow from it, pretty sure it goes off after a short while though. It cant be helping matters though

 

[RustyMojo]

I do indeed Russ and I've noticed the dim glow from it, pretty sure it goes off after a short while though. It cant be helping matters though

I sat in my car for 10 minutes messing around on my phone and didn’t notice it ‘turn off’ figured it was some residual power in the Led unit....but who knows, maybe worth swapping out and seeing

 

[DomP182]

It was draining beforehand to be honest just that it's got worse as the weather has cooled and I'm using it less, I say less I could hardly use it less😆