Charging car battery via the accessory socket?

Pathfinder

Senior Member
Joined
Dec 21, 2011
Messages
814
Reaction score
18
Age
63
Location
Gourock
Your Mercedes
CLC 220 CDi Sport Diesel Year 2008
Yeah me too but there is no way I'd jump my 230 from another car. This on the other hand should be a safer option.
If you feel your not competant to do a jump start, ask someone to do it for you. Most people can do it without any trouble, it's not that difficult.
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
If you feel your not competant to do a jump start, ask someone to do it for you. Most people can do it without any trouble, it's not that difficult.
Cheeky git!
The r230 is well known for electronic issues when being jump started. For that matter so is the r129 which has a predisposition for any electrical spike to blow the roof controller. There are ways to minimise the risk but that's all it does - minimise the risk.
I'd rather make the process of restarting the vehicle risk free if possible and the £160 one does that as well as anything can.
My 100% preferred option is to use the CTEK to get enough in to restart but thats not always possible either due to location or time.
I think if you looked back at my posting history you'd realise just what an insulting comment that was.
 

EmilysDad

Senior Member
Joined
May 8, 2012
Messages
12,120
Reaction score
5,664
Location
Bury Lancs
Your Mercedes
ML350
I can never get my head round these spikes etc from jump starting from AN Other car. Providing the donor car is not running (and the leads aren't connected arse about face), I can't see the difference between another car & a jumper pack ..... :confused: but willing to be proved wrong.
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
I can never get my head round these spikes etc from jump starting from AN Other car. Providing the donor car is not running (and the leads aren't connected arse about face), I can't see the difference between another car & a jumper pack ..... :confused: but willing to be proved wrong.
It comes about as a result of the load on the battery.
If there is a high load on the alternator its producing a lot of power. Sudden disconnection of the second battery means there is a moment in time where the regulator has to adjust and in that moment of time as the current is pretty much fixed the voltage will spike to release the power. This is why we turn on the headlights, heated rear window etc before disconnecting the battery - the effective percentage change in load is lower so the spike is smaller. The spike is only in the order of milliseconds but its enough to kill sensitive electronics - especially when the designer has omitted to include adequate spike protection circuitry.
A jump start pack has a lower capacity hence will more rapidly recharge from the car (if indeed it recharges from the car at all) and has less of a drain when is charging so less impact when disconnected.
A capacitive device has smart circuitry which can soft disconnect when it senses the car has started (i.e. car voltage greater than pack voltage).
 

Pathfinder

Senior Member
Joined
Dec 21, 2011
Messages
814
Reaction score
18
Age
63
Location
Gourock
Your Mercedes
CLC 220 CDi Sport Diesel Year 2008
Cheeky git!
The r230 is well known for electronic issues when being jump started. For that matter so is the r129 which has a predisposition for any electrical spike to blow the roof controller. There are ways to minimise the risk but that's all it does - minimise the risk.
I'd rather make the process of restarting the vehicle risk free if possible and the £160 one does that as well as anything can.
My 100% preferred option is to use the CTEK to get enough in to restart but thats not always possible either due to location or time.
I think if you looked back at my posting history you'd realise just what an insulting comment that was.
Cheeky git? What's that supposed to mean ? You are a bit touchy. I never looked at your post history, however I did look at your profile where you state you are an IT Consultant, so not a trained mechanic in my book, so suspected that your knowledge on technical issues was limited, as you seemed to make out a jump start is a risk process?

My comments on this thread are relating to my car, a CDi 220 sport, where the Mercedes manual for the car actually explains where and how to connect jump leads to the car, in the event that a jump start is required, so how can it be wrong to do so?

Suggest you calm down a bit.
 
Last edited:

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Cheeky git? What's that supposed to mean ? You are a bit touchy. I never looked at your post history, however I did look at your profile where you state you are an IT Consultant, so not a trained mechanic in my book, so suspected that your knowledge on technical issues was limited, as you seemed to make out a jump start is a risk process?

My comments on this thread are relating to my car, a CDi 220 sport, where the Mercedes manual for the car actually explains where and how to connect jump leads to the car, in the event that a jump start is required, so how can it be wrong to do so?

Suggest you calm down a bit.
Really?
You made an erroneous assumption on my skills. I may be an IT consultant but I probably have more spanner wielding experience than anyone who hasn't been a paid car mechanic having spent years in motorsport as a race mechanic and having built several class winning competition vehicles (some at international level). Someones profession does not define their abilities.

Your comments may be valid to your vehicle but I have no doubt someone jump starting an SL (or CL or S class) would very likely fry their electronics if they didn't take great care (and thats NOT covered in the handbook). That was my point.

Great that you have the ability to jump start your vehicle but frankly I wouldn't let you within a 100 yards of mine with a set of jump leads in your hands. I wouldn't let anyone (outside a trusted indy) anywhere near them if it had a flat battery as I understand the risks involved.

I get you're happy with jump leads but there are several amongst us who prefer a safer way to start their cars due to the sensitivity of the electronics which from your comments would appear to be something you were not aware of in spite of apparently being a trained mechanic.
 

Naraic

Moderator
Joined
Mar 4, 2010
Messages
10,686
Reaction score
1,274
Your Mercedes
2005 CL500.
Now now you two..though a competent member would realise how competent Alistair is in things car related.
 

umblecumbuz

Senior Member
Joined
Sep 20, 2010
Messages
4,431
Reaction score
1,875
Location
Wales and Gozo
Your Mercedes
S204 and CLC 204 cdi, MX5, Kia Soul
Maybe Pathfinder would care to get his car jump started a few times, and see if he gets away scot free?

It ain't an easy hassle-free process with many cars today Mr Pathfinder - including Mercs - although thankfully for you, your's is a bit less prone to electronic failures through spikes than many.

The risk is real, and potentially costly. You pays your money and you makes your choice.
 

Pathfinder

Senior Member
Joined
Dec 21, 2011
Messages
814
Reaction score
18
Age
63
Location
Gourock
Your Mercedes
CLC 220 CDi Sport Diesel Year 2008
Now now you two..though a competent member would realise how competent Alistair is in things car related.
and I'm not?....a bit one sided eh?
 

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
Let’s keep this friendly guys, only people trying to help out and also learn where appropriate.....
 

Pathfinder

Senior Member
Joined
Dec 21, 2011
Messages
814
Reaction score
18
Age
63
Location
Gourock
Your Mercedes
CLC 220 CDi Sport Diesel Year 2008
There is no way I am going to prevail over any discussion on here, as you are all obviously on first name terms with each other and back each other up, as and when required,...... even when wrong.

No futher comment from me.
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
There is no way I am going to prevail over any discussion on here, as you are all obviously on first name terms with each other and back each other up, as and when required,...... even when wrong.

No futher comment from me.
What pray tell was wrong in my posts?
 
OP
L John

L John

Senior Member
Joined
Nov 24, 2013
Messages
2,860
Reaction score
553
Location
UK
Your Mercedes
W204 C350 Petrol Elegance
  • Thread Starter
  • Thread starter
  • #53
ok, I will go and get a charger then.
It comes about as a result of the load on the battery.
If there is a high load on the alternator its producing a lot of power. Sudden disconnection of the second battery means there is a moment in time where the regulator has to adjust and in that moment of time as the current is pretty much fixed the voltage will spike to release the power. This is why we turn on the headlights, heated rear window etc before disconnecting the battery - the effective percentage change in load is lower so the spike is smaller. The spike is only in the order of milliseconds but its enough to kill sensitive electronics - especially when the designer has omitted to include adequate spike protection circuitry.
A jump start pack has a lower capacity hence will more rapidly recharge from the car (if indeed it recharges from the car at all) and has less of a drain when is charging so less impact when disconnected.
A capacitive device has smart circuitry which can soft disconnect when it senses the car has started (i.e. car voltage greater than pack voltage).

Not disagreeing with any of that but the bigger issue for me is it's almost impossible to get a good instant connection with jump leads.
Some lead acid jump start packs have a switch to turn power on after connection but jumping from another car means using un-switched cables, so the last clamp to be connected will gets a hit/miss contact several times which is very bad for electronics due to back EMF from coils.
People that can't see any difference between an internally switched smart jump starter and a jump from another car are blind to the issues.
I don't mind helping people to understand the difference but some people either don't want to know or are incapable of understanding.

Assuming I had no jump starter, if someone had a pair of jump leads and asked if they could get a jump start from my car, I would absolutely refuse even if they wanted me to connect them up.
It's not worth the risk even if it only fries one in a thousand when connected up following the correct procedure.
People that have done it a dozen times will claim it does no harm if they got away with it.
One of my favourite sayings is you can run across the road a dozen times without looking and have no problem, it doesn't mean it's safe though.
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Not disagreeing with any of that but the bigger issue for me is it's almost impossible to get a good instant connection with jump leads.
Some lead acid jump start packs have a switch to turn power on after connection but jumping from another car means using un-switched cables, so the last clamp to be connected will gets a hit/miss contact several times which is very bad for electronics due to back EMF from coils.
People that can't see any difference between an internally switched smart jump starter and a jump from another car are blind to the issues.
I don't mind helping people to understand the difference but some people either don't want to know or are incapable of understanding.

Assuming I had no jump starter, if someone had a pair of jump leads and asked if they could get a jump start from my car, I would absolutely refuse even if they wanted me to connect them up.
It's not worth the risk even if it only fries one in a thousand when connected up following the correct procedure.
People that have done it a dozen times will claim it does no harm if they got away with it.
One of my favourite sayings is you can run across the road a dozen times without looking and have no problem, it doesn't mean it's safe though.
I have modified jump leads for use on my 210/Smart (neither of which are known for susceptibility to spikes so I'm reasonably happy to use jump leads on them - unlike the two SLs or SWMBO's MINI). I cut both cables and added an Andersen connector into the leads so the clamps can be connected then the two connectors firmly and quickly pushed together. Same for the disconnect - a quick pull gives a single instant disconnection event.
 
OP
L John

L John

Senior Member
Joined
Nov 24, 2013
Messages
2,860
Reaction score
553
Location
UK
Your Mercedes
W204 C350 Petrol Elegance
  • Thread Starter
  • Thread starter
  • #55
I have modified jump leads for use on my 210/Smart (neither of which are known for susceptibility to spikes so I'm reasonably happy to use jump leads on them - unlike the two SLs). I cut both cables and added an Andersen connector into the leads so the clamps can be connected then the two connectors firmly and quickly pushed together. Same for the disconnect - a quick pull gives a single instant disconnection event.

That's great, it solves the problem inherent with jump leads but people will argue it's not necessary.
 

Chrishazle

Senior Member
Joined
May 25, 2009
Messages
4,860
Reaction score
2,606
Location
Nr Ashford, Kent
Your Mercedes
S204 2008 C220CDI Elegance Estate Auto, 2008 R171 Facelift SLK280
If only TV was still with us to give chapter and verse and not be questioned the way LK has been! One of the first lessons I learnt from this forum and t'other side was the risk to the car's SAM's of voltage spikes if connecting jump leads or possibly even turning on a connected high rate charger. 1 fried SAM equates to one large repair bill, so I read and learnt, but thankfully have not had to jump start either of the MB's I've owned (touches wood rapidly!!).
 

ZZZZ

Senior Member
Joined
Sep 19, 2014
Messages
3,671
Reaction score
1,613
Your Mercedes
.
I cut both cables and added an Andersen connector into the leads so the clamps can be connected then the two connectors firmly and quickly pushed together.
I'd like to see that, please (and replicate, naturally ;) ) - I bought a jump lead set a few years ago, and even though I never used it yet, it's better be protected.

The battery-less jump pack is definitely on the list now, for my next purchase.

I also got an OBD leads kit - to keep the car powered, when swapping batteries - probably won't be used for a good few years (if ever), as I fitted a brand new Varta last September :)
 

umblecumbuz

Senior Member
Joined
Sep 20, 2010
Messages
4,431
Reaction score
1,875
Location
Wales and Gozo
Your Mercedes
S204 and CLC 204 cdi, MX5, Kia Soul
I also got an OBD leads kit - to keep the car powered, when swapping batteries - probably won't be used for a good few years (if ever), as I fitted a brand new Varta last September :)

Off thread really, but this is a gismo that I've had for years. Put any slave battery in the drivers footwell, plug it in to the obd port via my gismo, then disconnect the car's normal battery. I bought one originally just to save my data and save the hassle of re-entering date and time, but it also saves spikes and keeps continuity.
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
I'd like to see that, please (and replicate, naturally ;) ) - I bought a jump lead set a few years ago, and even though I never used it yet, it's better be protected.

The battery-less jump pack is definitely on the list now, for my next purchase.

I also got an OBD leads kit - to keep the car powered, when swapping batteries - probably won't be used for a good few years (if ever), as I fitted a brand new Varta last September :)
Remind me when I next see you to give you a small 12v battery. I picked up a few that were unused and being binned.
 


Comand (Europe) Ltd are the leading specialists in supplying and fitting Comand, Linguatronic, Media interface kits, UHI phone, IPod interfaces and much more.
Top Bottom