203 Battery Change Procedure

cleverdicky

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Also the majority of people forget that a car battery is 'alive' for want of a better description. There is an chemical / organic process going on constantly.
By flattening a battery by leaving lights on say, it will recover partially by itself. If you then use a booster to bring up the p.d voltage, that is often enough for your own battery to provide enough power.
People assume you are sucking many amps from a booster or slave car battery.
If you just connect a booster and slave car battery to your own,and WAIT, it will very often assist / recover your own battery without sucking lots of power from another.
Having a donor car engine running while you try and start your own, serves no purpose.
 

taxii

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Where are you Toad? If your in Bristol I can pop round with a spare battery and Iv'e also got a jumpstart charger aswell.
 

toadoftoadhall

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Where are you Toad? If your in Bristol I can pop round with a spare battery and Iv'e also got a jumpstart charger aswell.
thanks for the offer, unfortunately, I am up in Worcester.
Battery is going pretty much flat if not used in about 4 days.
So what if...
I wait until its a bit discharged, take it out.
re-connect it to the charging points ( its already a bit flat so shouldnt spike, yes?)
then connect new battery.
?
 

The Pan Man

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Toad, Not seen you posting for a long time. This is my own experience from about 2005 / 2006 from a Mobilo Techie. I left the parking light on somehow. Techie turns up car is nose in to the garage. I tell him what's up he says ok. Nudged the R320 a little closer and removed a heavy duty set of jump leads from the Mobilo car removed a small access plate in the fron bumper hooked up the jump leads for about 15 mins the Mobilo vehicle on tickover all the time explained to me that the electrical system on my car E270 CDi needed to be woken up as it would have closed down to try and preserve the battery. After about 15 mins he turns my key and away we go, same battery on the car when I sold it never any problems. This was when I rigged up the solar panel chargers. They are now on the third car. If you have a deep search you might find the original post.
 

television

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thanks for the offer, unfortunately, I am up in Worcester.
Battery is going pretty much flat if not used in about 4 days.
So what if...
I wait until its a bit discharged, take it out.
re-connect it to the charging points ( its already a bit flat so shouldnt spike, yes?)
then connect new battery.
?

That will not help, it just needs some battery with 12 volts in it to keep the circuits live, just something with a pair of crocodile clips.

Do not leave the key in ignition when changing the battery
 

toadoftoadhall

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OK, done and dusted. Did as much as I could to avoid anything bad, but a confliction I found. Here it says to disconnect the positive first, most other sites (RAC) says to disconnect the negative first. Which is the best, and why, (a bit like being back in school with exams isnt it). Also, is there a correct order to connect the battery, pos or neg first.
thanks for all your help, and offers Taxii, great site. Havnt been around much cause the old girls been running ok. I have the jumping door lock thing, drivers door. An annoyance, but for a £400 fix, I will live with it until the car dies. Had a MAF failure last summer, but a garage in Evesham sorted it all out with diag and repair for £100, so was happy with that.
I have a fuel pump leak, slight, which rots the V-belt, but again, at £500 for a fix, I will just change the belt occasionally.
thanks again
toad
 
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HERBIEMERCMAN

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you disconnect the neg first as there is no potential, so no spike voltage, then when you reconnect the next battery it is the opposite, you connect the pos first and the neg last. herbiemercman.
 

BSF Whitworth

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power packs

Kit alert! After some research, invested £99 in a Halfords 200 power pack. Bit more than some. But this is the veritable swiss army knife of power packs.Good quality components.built in compressor with gauge.
Versatile, with usb, clamps and accessory outs. Built in light and 240v inverter out. Intelligent charger inbuilt. wrong connection alert.Internal battery condition led's.
They even give you a male to male accessory lead. It does everything.
I even found two uses they had not thought of describing in the manual;
1) Want to disconnect your car battery? First plug the pp into a 12v socket
and it will maintain your system power and settings. Then disconnect your battery and give it a good seeing to in the garage.

2)With your pp mains connected, ie charging, a 12v socket in the car can be used to give a TOPUP charge from the intelligent charger. Only do this if the pp battery is fully charged.
ps I have no connection in any way to Halfords.
 

television

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The only thing here is the socket in the car is dead until the ignition switch is turned to 1
 

BSF Whitworth

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The only thing here is the socket in the car is dead until the ignition switch is turned to 1

Thanks for pointing that out tv. Does that apply to all the 12v sockets. If you have external socket that might be always "live".
 

television

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There are no live sockets fitted to any mercedes in the cab, some add an all time live in the boot for fridges and other things.

Cigar lighters are always key 1, a real all time live socket connected to the battery direct via fuse is the safe way,,, odd things can happen when playing with the battery with the key in the ignition
 

Colin_P

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...disconnect the positive lead from the battery and tape up fully, this will stop any shorts...

I didn't have any tape, so I had to hold the positive lead in my left hand while removing the old battery and putting the new one in with the right.

My back hurts now.
 

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