Battery Charging

[Adsnew32]

Morning,

Checked the main battery voltage on my Merc C250 CDI last night as i noticed the ECO light no longer lights up. (have done a few short trips)
12.32v with engine off &
14.8 with engine running.

Was thinking of giving it a charge this weekend, disconnect it but leave it in the car whilst charging it (to save lifting it out and undoing the clamp) by connecting a charger straight to the battery terminals. Is this recommended?

I've not had chance to look at the date on the battery yet, but reason behind thinking it may need a charge is its only done 2,000 miles in a year. Previous owner opted for his E Class instead apparently.

Its done a 100 mile trip since purchase and the Eco light was on then but after only a couple of short trips the Eco light is no longer on, it prompted me to check it.

Not great with cars, so any info is appreciated. I'm wondering whether a charge would recover it or whether at that voltage its past its best.

 

[Gazwould]

Stop start is bad for engine components .

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Charge from points near battery , my battery is less V than that @ 12 / 12.1 V yet cranking isn't slow and car starts .

Luckily on a 204 you can disable the Stop Strain system by simply removing the auxiliary battery fuse , removing a terminal lead or totally removing the battery all together saving 5 Kg , now that's Eco !

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I've had fuse disabled since early last year then decided to totally remove the auxiliary battery . Couldn't be happier .

 

[Adsnew32]

What a guy in the YouTube video is! SOLD, im not a fan of start stop anyways and if your cars at less voltage than mine and starting ok ive nothing to worry about.

However, i will ask, you said 'Charge from points near battery', does this mean its safe for your ECU and other electronics to just connect a charger to this positive point and the earth point thats nearby with the battery still connected?

Cheers

 

[Gazwould]

Been doing it for years , that's what everyone does it's a direct link to the battery .

Glad you're not manufacturer and gubberment brainwashed , no one should fall for these lie telling machines..

Here's a good vid too , lol .

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[Gazwould]

What a guy in the YouTube video is! SOLD, im not a fan of start stop anyways and if your cars at less voltage than mine and starting ok ive nothing to worry about.

12 /, 12.1 V is my charged up to voltages , when I first put it on it can be 11.7 V , so you've got some time yet , still starts without a struggle .

Yet they can go suddenly so I've pre selected the next .

Luckily ( not quite the word I'd use ) my super value for £ battery charger has a display for the voltage etc and not some Close Encounters of the third kind spaceship lights .

My other older cars with replacement lead acid batteries start from 12.3 V and charge to 13.6 V .

I can only think the Mercs 10 year original is still going at low voltages because it's an AGM deep cycle .

 

[chic0821]

Perhaps this will help regarding battery charge. Engine off

 

[190]

However, i will ask, you said 'Charge from points near battery', does this mean its safe for your ECU and other electronics to just connect a charger to this positive point and the earth point thats nearby with the battery still connected?

Your owners manual will specify a safe charging voltage with the battery still connected, mine says 14.8 volts.

In practice you will be fine with a modern charger in normal modes. Don't use de-sulphation or equalization modes.

 

[grober]

Its perfectly safe to charge the main battery from the positive and negative terminals under the bonnet without disconnecting the battery using an intelligent charger such as a CTEK. No modern Mercedes should be left more than three weeks without some form of top up battery charge. If cars previous owner failed to do this the battery may be past its best. In addition to the main battery in the engine compartment you may have stop start battery in the trunk.

 

[Gazwould]

Did someone say CTEK !

Can't believe they didn't get them to play a tune when they're charged up .

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[Adsnew32]

Thanks, I've got a Ring 12v 4amp charger which i purchased only a year ago so ill use that and charge the car this weekend (weather permitting)

 

[Adsnew32]

Yes it has what i've read to be an Aux battery in the boot too.

 

[Petrol Pete]

What a guy in the YouTube video is! SOLD, im not a fan of start stop anyways and if your cars at less voltage than mine and starting ok ive nothing to worry about.

However, i will ask, you said 'Charge from points near battery', does this mean its safe for your ECU and other electronics to just connect a charger to this positive point and the earth point thats nearby with the battery still connected?

Cheers

That was my reaction the first time I saw Scotty !

 

[Adsnew32]

Actually thinking about it, ive got an Optimate 2 i sometimes use for my bike's battery which i could use to top my car battery up at weekend. Bit of a smarter device than the Ring charger i mentioned.