2003 C200K battery

[BARMY]

RAC replaced a very old battery 6 months ago. The new battery was so flat today that it wouldn’t turn the engine over. Called RAC. They tested it and said it was so discharged it needed replacing. I said: “fine, go ahead, it’s under warranty”. The guy said it was too far discharged to be still under warranty. He tested for any discharge - none. He tested the alternator - ok. The car was last used 7 days ago.
I’ve emailed RAC asking for my money back for the second battery.
But is there a known fault which uses up a battery every six months? And is there a fix?

 

[markjay]

Did you keep the old battery? If so then try leaving it for a couple of days connected to a CTEK trickle-charger.

Also, is it an AGM battery with? If so, then with AGM batteties the trickle-charger may need to be 'cheated' in order to resume charging if the voltage falls below a certain level. This is done by connecting a second (good) battery in parallel, so both are being charged, then disconnecting the good battery once the old battery reached the minimum voltage level and can continue and be charged on its own from that point onwards.

 

[AMGeed]

The RAC battery should have had a minimum of 3 years warranty.
For it to fail after 6 months should mean a free replacement

 

[BARMY]

No, I don’t have anywhere to keep an old battery so RAC took it away.
I don’t have any kind of trickle charger and would have no way of safely connecting one up.
I hope the replacement battery will be ok, and that the 6 month old one was simply faulty, and that there is no mystery drain that the RAC guy failed to identify.
But, just in case, are the dashboard solar panels that plug into the cig lighter any good?

 

[BARMY]

The RAC battery should have had a minimum of 3 years warranty.
For it to fail after 6 months should mean a free replacement

 

[BARMY]

Thanks. I’ve told them that.

 

[wongl]

But, just in case, are the dashboard solar panels that plug into the cig lighter any good?

Not generally useable in the Mercedes because the cigarette lighter socket is disconnected from the 12v supply when the engine is switched off.

 

[BARMY]

Not generally useable in the Mercedes because the cigarette lighter socket is disconnected from the 12v supply when the engine is switched off.

Thanks for that. Could I get it wired direct or would that upset some other electrics?

RAC have just responded to my request for a refund for the replacement battery.
They say that as the one they sold me 3 months ago was down to 10.9 volts it must have been misused, or there was a drain on it, or it had been left a long time. It hadn’t been misused (how do you misuse a battery?). Their patrol tested the car, and confirmed there was no drain. It had been left 3 days.

In any case, I will have jump started 100s of brand new cars over my years as a car salesman and not needed to replace the batteries.

And I will have trickle charged my own race cars scores of times after they’ve been left for weeks and have been flat, and found the batteries lasted for a long time thereafter.

As I now live in an apartment, I can’t trickle charge a battery on the car, otherwise I’d have done that. And I gave away my jump leads when I left Australia.

The RAC patrol would have realised that I didn’t try jump starting or trickle charging. So I’m beginning to wonder if he has a target for battery sales, and took me for a mug when he told me I should write in to claim back the cost of the battery as it was only 3 months old, and it was a shame it wasn’t a warranty claim because it was below 11.9 volts?

Meanwhile, I’ve told the RAC to refund me and bring back the old battery, otherwise we can go to court.

 

[190]

A directly connected solar charger will work but get something a little better than the a cheap 1.5W version as the one I had was hopeless. You need something more like 5 or 6 watts. Any solar charger will only produce the rated output in ideal conditions i.e. square on to the sun and not through a windscreen. In practice you will be lucky to get a tenth of the rated output.

 

[BARMY]

There are cheap 20W ones on eBay. Lots of them hedge their bets by showing the panel being outside on a boat, or on a walkers backpack. There is one, however, which actually shows a picture of it on a car dashboard. So I’ll ask them if it works inside a car and let you know.

 

[W1ghty]

There are cheap 20W ones on eBay. Lots of them hedge their bets by showing the panel being outside on a boat, or on a walkers backpack. There is one, however, which actually shows a picture of it on a car dashboard. So I’ll ask them if it works inside a car and let you know.

What about this (I use one )

MAYPOLE MP7423 Electronic Car Battery Charger 3.8 A Fast/Trickle/Pulse Modes | eBay

Find many great new & used options and get the best deals for MAYPOLE MP7423 Electronic Car Battery Charger 3.8 A Fast/Trickle/Pulse Modes at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

edit , sorry just seen you can’t trickle charge

 

[wongl]

Thanks for that. Could I get it wired direct or would that upset some other electrics?

RAC have just responded to my request for a refund for the replacement battery.
They say that as the one they sold me 3 months ago was down to 10.9 volts it must have been misused, or there was a drain on it, or it had been left a long time. It hadn’t been misused (how do you misuse a battery?). Their patrol tested the car, and confirmed there was no drain. It had been left 3 days.

In any case, I will have jump started 100s of brand new cars over my years as a car salesman and not needed to replace the batteries.

And I will have trickle charged my own race cars scores of times after they’ve been left for weeks and have been flat, and found the batteries lasted for a long time thereafter.

As I now live in an apartment, I can’t trickle charge a battery on the car, otherwise I’d have done that. And I gave away my jump leads when I left Australia.

The RAC patrol would have realised that I didn’t try jump starting or trickle charging. So I’m beginning to wonder if he has a target for battery sales, and took me for a mug when he told me I should write in to claim back the cost of the battery as it was only 3 months old, and it was a shame it wasn’t a warranty claim because it was below 11.9 volts?

Meanwhile, I’ve told the RAC to refund me and bring back the old battery, otherwise we can go to court.

You could hardwire it, but if you do, try to hardwire it to the jump start points in the engine bay to avoid splicing into your car harness.

If you live in an apartment, you could consider getting one of these USB jump start pack. I have no idea how well they work as I have no personal experience of using them. However, I have seen videos on YouTube where a frozen Mercedes with no cranking power can be started with something similar.

Ultimate Speed Powerbank with Compressor - at Lidl UK

Ultimate Speed Powerbank with Compressor - 4-in-1 power bank with powerful Li-Ion battery (14Ah) Includes compressor with integrated compressed air hose

www.lidl.co.uk

 

[steveskeggy]

A solar charger is like putting a sticking plaster on a broken leg.
A modern car will always have a discharge on it, alarms and their sensors dont work on fairy dust.
leaving a car for three days CAN lower the voltage to 10.9, my S55 does, leave it for more than a week, and it will be flatter than roadkill, so that comment from the RAC is a load of cobblers (Your race cars dont have alarms, or stuff that runs when the ignition is turned off).
Possibly the only way to stop discharge altogether is to disconnect the battery after parking up, however this will disable the alarm, and possibly invalidate your insurance if the car gets nicked.
If you go to Halfords, you can buy a jump start pack, save fannying around with jump leads, if you need to charge the battery, take it off the car and charge it in your apartment.

 

[190]

If there is no fault with the car then the alarm should not discharge the battery in 1 week. The most I've measured on a Mercedes is 35mA or just under 6 A/h per week and most are much less than that. With an 85 A/h battery the car should be good for at least a month unless the battery is on it's last legs.

If there is a fault then anything is possible. I had a fault that would flatten the battery in 1 week which I cured simply by disconnecting the battery overnight. When reconnected the self discharge rate had returned to normal.

 

[BARMY]

A solar charger is like putting a sticking plaster on a broken leg.
A modern car will always have a discharge on it, alarms and their sensors dont work on fairy dust.

Would a solar charger work though?
And is 17 years old “modern”?
And the RAC guy said there was no discharge. So is this simply a matter of the replacement battery being no good?

 

[BARMY]

If there is no fault with the car then the alarm should not discharge the battery in 1 week. The most I've measured on a Mercedes is 35mA or just under 6 A/h per week and most are much less than that. With an 85 A/h battery the car should be good for at least a month unless the battery is on it's last legs.
THE RAC SAY THERE WAS NO DISCHARGE.

If there is a fault then anything is possible. I had a fault that would flatten the battery in 1 week which I cured simply by disconnecting the battery overnight. When reconnected the self discharge rate had returned to normal.
I DON’T WANT TO WORK ON MY CAR EVERY TIME I LEAVE OR RETURN HOME. I’D RATHER SELL IT AND GET ONE THAT DOESN’T HAVE FLAT BATTERIES. THE RAC SAID THERE WAS NO DISCHARGE. WHAT OTHER SORT OF FAULTS COULD THERE BE THAT WOULD FLATTEN A BATTERY?

 

[steveskeggy]

A solar charger "may" work, I dont know, but I have read a couple of times that they are not much use on a car because of the low output.
Even if they did work, where would you put it? Would it work on the dashboard? Sat Nav/radio/TV antennas dont, neither do reactolite glasses (I know these use other properties).

It doesnt matter what the RAC man said, if your car has an alarm, it will discharge with the ignition off, then there is the clock, the radio memory, and anything else the bloody Germans could think up to make our life harder...

Modern car? Yes, I would think anything post 2000 could be classed as modern, if not before, you could only think of a Dodge Viper as a modern car, yet it was first produced in 1991.

If you want to go the disconnecting way, but dont want to faff around disconnecting the battery, there is always the battery isolator switch method, 15 quid from Halfrauds, its still a sticking plaster if you use the car regularly, but if the car is left for days at a time, its not such a bad idea.
The problem is, a discharge, unless its a massive discharge where things get hot, can be a bitch to trace.

What is the make of the battery? My S55 is fussy about the brand, I had one from KwiKFart once which lasted 6 months. Bosch tend to last around a year, but the Yuasa one I have on at the moment seems to have lasted quite well, guessing the RAC would get one from Quackfart.

 

[BARMY]

A solar charger "may" work, I dont know, but I have read a couple of times that they are not much use on a car because of the low output.
Even if they did work, where would you put it? Would it work on the dashboard? Sat Nav/radio/TV antennas dont, neither do reactolite glasses (I know these use other properties).

It doesnt matter what the RAC man said, if your car has an alarm, it will discharge with the ignition off, then there is the clock, the radio memory, and anything else the bloody Germans could think up to make our life harder...

Modern car? Yes, I would think anything post 2000 could be classed as modern, if not before, you could only think of a Dodge Viper as a modern car, yet it was first produced in 1991.

If you want to go the disconnecting way, but dont want to faff around disconnecting the battery, there is always the battery isolator switch method, 15 quid from Halfrauds, its still a sticking plaster if you use the car regularly, but if the car is left for days at a time, its not such a bad idea.
The problem is, a discharge, unless its a massive discharge where things get hot, can be a bitch to trace.

What is the make of the battery? My S55 is fussy about the brand, I had one from KwiKFart once which lasted 6 months. Bosch tend to last around a year, but the Yuasa one I have on at the moment seems to have lasted quite well, guessing the RAC would get one from Quackfart.

 

[BARMY]

Thanks Steve for your comprehensive reply.
I just find this whole situation so odd. I used, for instance, to have two cars - a 2010 Skoda Superb and a 2004 Mazda MX5. There will definitely have been times when one has been left for much longer than a week, and most days only used for 5 minute trips with longer trips being more than a week apart.

The Skoda’s original battery lasted 8 years, and the Mazda’s 12 years. There were maybe a few jump starts during that time, but the batteries always recovered by the car being driven, until their final demises, whereas this battery has been flat only once, and was condemned. It makes you wonder whether the RAC’s meters have a switch to make them show 10.9 volts??????

House solar panels have glass on them, so there’s a possibility that on the dashboard might work, although windscreens are laminated glass. I haven’t yet had a confirmation from the eBay vendor about this. Perhaps that silence speaks volumes? Although the AA offer several models that they say are designed to work on the dashboard and extend battery life for rarely used cars and caravans! They also have one that plugs into the OBD port. Is that permanently live and safe to plug into on Mercs?

It sounds like you must be right, and the RAC man wrong, in that there must be a discharge. But if there is a discharge, and he’s missed it, surely it must be a tiny one, which surely shouldn’t flatten a 6 month old battery on a regularly used car after only 3 days of non use? In which case, maybe the battery was faulty? He had it on his van. Don’t know the make. Looked the same as the previous one.

This is so frustrating, especially as the car is otherwise so good (apart from the parking sensors sounding all the time whenever reverse is selected, and the squeaks from the rear suspension).

 

[190]

House solar panels have glass on them, so there’s a possibility that on the dashboard might work, although windscreens are laminated glass.

There is no question that it will work through the windscreen but my experience was that the output was greatly reduced which you will need to factor in when choosing the size and output of the panel.