Battery Charging in situ

[moosehead]

I'm on the verge of ordering the CTEK CT5 charger which has the lower output voltage (MB handbook stipulates a maximum charging voltage of 14.8V) and is designed for start / stop batteries but can be used on standard units. There seems to be many conflicting ideas on whether you need to disconnect the battery or charge it in situ connected. My MB indy recommends disconnecting although CTEK confirm you can safely charge with it connected.

To confuse matters further I had to take the XC60 to the Volvo dealership this morning. Whilst there I took the opportunity to ask them about charging the battery as I frequently get a 'low battery charge' light after listening to the radio with the engine off (apparently a common Volvo problem). They advised disconnecting the batterybefore charging! Does anyone (indies included) have a definitive answer to this? Access to the battery on the W203 is a pain as you have to remove the filter housing to the heater fan as is the Volvo with various bits of trim / panels you have to remove.

 

[EmilysDad]

I've never had problems charging batteries in situ on any other car. I've used the the connector that comes with a CTek charger that over comes access problems. Alternators charge in situ

 

[Naraic]

Some cars come with a Ctek as standard equipment ( Ferarri) and they definitely do not disconnect the battery first. Think about it...not very convenient. I've had my Ctek for years...and never disconnected it...in fact I have a convenience connector permanently wired in.

 

[McDonald]

My CTek works wonderfully, in situ. Disconnecting batteries seems to bring a cascade of difficulties on these complex cars.

 

[Blobcat]

I've never disconnected any of mine (cars or bikes) when charging with a CTEK or Optimate. Like Naraic above my local Porsche dealer has all the cars on chargers and all the batteries are still connected.

 

[flowrider]

Like posters above I have been using a CTEK trickle charger for the last 3 years and never disconnected the battery. On a lot of cars having no power from the battery can cause all sorts of electrical issues.

 

[EmilysDad]

also on my car, the main battery is under my seat so is anything but accessible.

 

[Wighty]

My Maypole charger has the easy access wiring permanently connected to the battery , never had a problem

 

[moosehead]

Thanks for all the comments. This has certainly allayed my fears. Have always disconnected batteries on older vehicles which didn't have complicated electronics and an ancient battery charger that probably didn't output clean DC however I certainly wouldn't relish trying to access / disconnect a battery on a modern vehicle especially this time of year.

 

[LostKiwi]

As with others, our r230 spends all the time not in use on charge with the battery connected to my 10A Ctek. Malcolm modified it to add a quick connect for the purpose. No issues to date.

 

[RhodieBill]

Just to add to the list, I've generally always charged in situ and connected.

 

[malcolm E53 AMG]

Yes as above shouldn’t be a problem now that intelligent chargers are available, I used to disconnect the battery with the old fashioned chargers to protect the alternator

 

[AMGeed]

Leaving the battery connected when charging isn't the problem on a W203 (or most other models)

Jump starting a W203 is the no no. All kinds of problems can occur if not done correctly.

 

[moosehead]

Leaving the battery connected when charging isn't the problem on a W203 (or most other models)

Jump starting a W203 is the no no. All kinds of problems can occur if not done correctly.

Oh dear, another can of worms! How do you jump start a W203 correctly? Obviously you have the positive 'flip up' connection point and then presumably the earth stud on the body.

 

[Botus]

a few common sense rules of engagement

never disconnect anything on modern cars, you'll just upset things unnecessarily
you should not go straight to the + - terminals on the battery,
modern chargers are clever enough to sense what happening and provide the right charge as and when required, but to do this as well as possible, it needs to sense the car's power usage with the key off. Going direct to the battery terminals circumnavigates this. Connect a charger to the positive terminal and the negative to a good earth away from the battery (or if its modern the + - points provided by the manufacturer)
it should be noted that modern cars need assistance all the time if its not a daily driver

 

[RhodieBill]

Oh dear, another can of worms! How do you jump start a W203 correctly? Obviously you have the positive 'flip up' connection point and then presumably the earth stud on the body.

I've had a W203 Coupe Jump-Started, no problem.

 

[AMGeed]

^ Obviously done correctly Bill.

I recall Malcolm (Television) posting of the dangers of frying the Sams and other problems if not done properly.

Don't ask me how, I've not owned a W203 so never bothered to find out

 

[AMGeed]

Here you go, just one thread on the pitfalls of jump starting a W203
https://forums.mercedesclub.org.uk/...ehicle-or-vice-versa-potential-issues.105834/

And another

https://forums.mercedesclub.org.uk/index.php?threads/c-class-w203-help-after-jump-start.78134/

 

[RhodieBill]

^ Obviously done correctly Bill.

I recall Malcolm (Television) posting of the dangers of frying the Sams and other problems if not done properly.

Don't ask me how, I've not owned a W203 so never bothered to find out

When I said "had" it was the AA man and I remember he connected to the Battery because I removed the Cabin Filter so he could get to it... But we subsequently found out, (after a lot of testing) that there was nothing wrong with the battery it was the Starter Motor because even on the Booster Pack nothing happened. So he checked the live to the Starter which showed nearly 13 volts.
So I bought a Starter on Ebay for £13 and got the garage to fit it....
But nothing went wrong with the car though and was fine after the Starter was replaced.

 

[bob 6600]

Some cars come with a Ctek as standard equipment ( Ferarri) and they definitely do not disconnect the battery first. Think about it...not very convenient. I've had my Ctek for years...and never disconnected it...in fact I have a convenience connector permanently wired in.

Ditto