Disconnecting The Battery W203 C220 CDI

[DMK/Happy]

How long a period can the battery be disconnected for? and will everything fire up again as normal when reconnected?

 

[Taffy7hfa]

Depends on the year and model , but I think your car will be ok being left without a battery.
The 270 was without battery for 2 months earlier this year and I had no problems at all when re-commissioning it.
Obviously some will require the code for the head unit.

 

[DMK/Happy]

Hi! Is this searing heat 29c difficult on wet cell batteries in the vehicle?

 

[Blobcat]

Hi! Is this searing heat 29c difficult on wet cell batteries in the vehicle?

No

 

[S500 Pete]

How long a period can the battery be disconnected for? and will everything fire up again as normal when reconnected?

If it is just while you are swapping the battery put a battery charger on the leads to keep the volts there while you change it.
Keeps the radio presets and everything

 

[DMK/Happy]

If it is just while you are swapping the battery put a battery charger on the leads to keep the volts there while you change it.
Keeps the radio presets and everything

That is a super suggestion!

 

[grahamcol]

If it is just while you are swapping the battery put a battery charger on the leads to keep the volts there while you change it.
Keeps the radio presets and everything

But is this really OK bearing in mind you're removing the battery load? I'd be worried doing this might cause some type of current/voltage surge.

 

[S500 Pete]

But is this really OK bearing in mind you're removing the battery load? I'd be worried doing this might cause some type of current/voltage surge.

Chargers are limited to maximum voltage so no surge.

 

[Chrishazle]

There's an emergency +ve terminal under the bonnet, IIRC NS towards the bulkhead under a red plastic cover, connect the charger +ve to that and the -ve to the top of the suspension mounts, then be careful taking the leads off the battery as even disconnected they'll still be live!!

 

[RhodieBill]

I bought one of these - saves a lot of hassle when changing the battery or removing the Battery for short periods.

 

[Rory]

Getting the battery out and back in on these is pretty tight (at least it is on mine) - not sure I'd fancy doing that with the system live!

Had my battery replaced by an AA guy - he was anxious to make sure the key wasn't in the ignition but other than that the awkward bit was actually getting the battery in (even with me holding the cables out of the way) and seated properly. He was a big guy, I think I'd have struggled on my own.

On my car it was found that the battery bay was half full of water - AA guy took the tray out (just a couple of bolts) and cleared the drain bung (it's part of the drain tube that comes down from the scuttle).

 

[RhodieBill]

That's why I bought one of these so as to not have the Key in and on Acc. Just connect it to the Live under the flap in the Engine Compartment and an Earth.

My Battery is in the Boot and relatively easy and safe to remove.

 

[grahamcol]

Getting the battery out and back in on these is pretty tight (at least it is on mine) - not sure I'd fancy doing that with the system live!

Had my battery replaced by an AA guy - he was anxious to make sure the key wasn't in the ignition but other than that the awkward bit was actually getting the battery in (even with me holding the cables out of the way) and seated properly. He was a big guy, I think I'd have struggled on my own.

On my car it was found that the battery bay was half full of water - AA guy took the tray out (just a couple of bolts) and cleared the drain bung (it's part of the drain tube that comes down from the scuttle).

On my 209 CLK which l think will be the same, l used a slave battery on the underbonnet live / earth points and made sure the battery cables were very well insulated with tape prior to attempting to drop the new battery in. It is a bit awkward but certainly doable.

 

[EmilysDad]

there has to be something wrong in the design of a car's electrickery if you can't just remove a battery & reconnect another without the palaver of connecting AN Other power supply.
I've yet to worry about what the 2nd battery on my car supplies if I ever needed to remove/swap the main battery from under my seat.

 

[EmilysDad]

I bought one of these - saves a lot of hassle when changing the battery or removing the Battery for short periods.

as the ciggy lighter is usually ignition live, you'd have to leave the ignition switched on ..... which is a whole other thread.

 

[RhodieBill]

as the ciggy lighter is usually ignition live, you'd have to leave the ignition switched on ..... which is a whole other thread.

Read POST #12......

 

[RhodieBill]

there has to be something wrong in the design of a car's electrickery if you can't just remove a battery & reconnect another without the palaver of connecting AN Other power supply.
I've yet to worry about what the 2nd battery on my car supplies if I ever needed to remove/swap the main battery from under my seat.

Personally I would never buy a car with a Battery under the Seat. Did it once, a 1971 Audi 100GL with the Battery under the back seat! Whoever thought that was a good idea was a complete a-hole!!

 

[Rory]

as the ciggy lighter is usually ignition live, you'd have to leave the ignition switched on ..... which is a whole other thread.

I think it's not very obvious but the suggestion involves using the 12V power supply plug and the cig lighter adapter together.

 

[Rory]

there has to be something wrong in the design of a car's electrickery if you can't just remove a battery & reconnect another without the palaver of connecting AN Other power supply.
I've yet to worry about what the 2nd battery on my car supplies if I ever needed to remove/swap the main battery from under my seat.

W203's have a reputation for blowing one of the SAMs when the battery is reconnected.

There's an old "how to", written by an indie, I think, here: https://forums.mercedesclub.org.uk/index.php?threads/203-battery-change-procedure.53197/

 

[EmilysDad]

Read POST #12......

I shall stand & face the corner