Connecting A Battery Charger

[DPS]

Advice please.
I have a 67 plate T6 Kombi 150 DSG with Stop/Start
I want to connect a CTEK MXS 5.0 Battery Charger to the van battery
The battery is a VARTA 7PO 915 105 A 12v 75Ah AGM

Do I connect the positive and negative clamps directly to the battery or do I have to connect one of the clamps to an earthing point?
The negative terminal has a do not connect symbol but someone told me this only applies when using jump leads.

Thanks in advance for your help.

 

[sparkzer]

connect directly to the battery for charging...your friend is correct the ground when jump starting should be on an earthing point.

 

[Dellmassive]

Use a chassis ground point if you want the van to register the charge into the battery..

Direct across the battery terminals will bridge out the sensor on the negitive battery pole....

.
Battery Chargers - How I Did It -
.
Which Jump Starter?
.
Lithium Lifepo4 12v Batteries - - - Time For An Upgrade ? - - -
.
Battery Charging - Main Battery Earth Point -
.
Dc-dc Charger (for Leisure Battery) -- How I Done It --
.

 

[travelvolts]

connect directly to the battery for charging...your friend is correct the ground when jump starting should be on an earthing point.

This is incorrect. You always charge with the negative cable connected to the vehicle body, never to the battery terminal.

 

[sparkzer]

This is incorrect. You always charge with the negative cable connected to the vehicle body, never to the battery terminal.

Can you expand upon why? Whilst i fully see the benefit when jump starting when ignition on, when the ignition is off it is my understanding that the shunt on the neg terminal will be doing nothing therefore I'm struggling t see the difference (other than making it more difficult to connect up the charger).

 

[Dellmassive]

@travelvolts is correct.

The shunt is active and monitoring power drain 24/7.

Any charge or discharge is monitored and logged 24/7 by the EMS energy management system which is is part of the ECU engine control unit.

Bypassing the shunt will end up with a misaligned power map of the battery SOC that's recorded as part of the EMS

 

[mmi]

Some related info on page 23 in ---> https://cardiagn.com/startstop-system-2009-ssp-426-online/

 

[travelvolts]

What Del said

 

[Dellmassive]

Ref @mmi link

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.

 

[sparkzer]

@travelvolts is correct.

The shut is active and monitoring power drain 24/7.

Any charge or discharge is monitored and logged 24/7 by the EMS energy management system which is is part of the ECU engine control unit.

Bypassing the shunt will end up with a misaligned power map of the battery SOC that's recorded as part of the EMS

Aha!..in that case it makes perfect sense and probably goes some way to explain why the batteries get flat pretty quickly with so many processes carrying on in the background 24/7.

I stand corrected and appreciate the additional info.

 

[Dellmassive]

Ironically, the idea of not using the battery neg post in older cars has nothing to do with this either.

The idea is that when SLA batteries are charged or discharged from a jump start or EHU charger they generate explosive hydrogen gas.

The body neg last/first is to that any spark from the jump lead/charge lead will not ignite any battery gassing..... or at least help reduce the risk of ignition.

 

[sparkzer]

The body neg last/first is to that any spark from the jump lead/charge lead will not ignite any battery gassing..... or at least help reduce the risk of ignition.

Another interesting point...tho surely it would be best practice to turn the charger on after connection and off before disconnection to prevent the spark possibility in the first place?

 

[Dellmassive]

Another interesting point...tho surely it would be best practice to turn the charger on after connection and off before disconnection to prevent the spark possibility in the first place?

Yes, absolutely.

But in a battery to battery jump start situation there is always a high current flow from the charged battery to the flat battery..... sparks will occur when the lead is connected or disconected.

Most modern jump packs use logic to detect a min voltage before connecting power to the leads.... to prevent sparking.

 

[sparkzer]

Most modern jump packs use logic to detect a min voltage before connecting power to the leads.... to prevent sparking.

I was going to mention the same, which is also true for modern chargers which look for correct polarity etc before allowing current to flow.

 

[DPS]

This is incorrect. You always charge with the negative cable connected to the vehicle body, never to the battery terminal.

Thank you for this, much appreciated.

 

[Martinc178]

Hi all
I have a battery charger wired to my leisure battery so when I plug the van into a mains power it charges the leisure battery. Does anyone know if it will it also charge the engine battery at the same time.
Or is it only one way charge from the engine battery?
if I need to charge the engine battery what type of charger will I need for the van is stop start.
Thanks
Martin

 

[Salty Spuds]

Hi all
I have a battery charger wired to my leisure battery so when I plug the van into a mains power it charges the leisure battery. Does anyone know if it will it also charge the engine battery at the same time.
Or is it only one way charge from the engine battery?
if I need to charge the engine battery what type of charger will I need for the van is stop start.
Thanks
Martin

Try using the search function & look at Dellmassives “how to’s”

 

[Dellmassive]

Hi all
I have a battery charger wired to my leisure battery so when I plug the van into a mains power it charges the leisure battery. Does anyone know if it will it also charge the engine battery at the same time.
Or is it only one way charge from the engine battery?
if I need to charge the engine battery what type of charger will I need for the van is stop start.
Thanks
Martin

some people will just add a second mains charger to starter battery,

some will move the charger to the starter and use the DC-DC AUTO VSR feature

some will just add the AMT12 smart reve5rs charger . . .

its all explained below.






see here for chargers - Battery Chargers - How I Did It -

here for battery monitoring - Battery Monitoring -- How I Done It --

here for "starter charge from LB" - [Guide] Battery Maintainer (for Starter battery) -- How I Done It --

here for Jump Packs - Which Jump Starter?


and here for the rest:

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Dellmassive`s -- "how I Done It" -- Thread
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[BoroBoy]

So, is it OK to charge via the 12v socket on the dashboard?

 

[Dellmassive]

So, is it OK to charge via the 12v socket on the dashboard?

yes....

upto 8A . . . . . above that the socket will start to get hot and possibly melt.

so no 10,20,30A chargers. (to use these you need to hard wire them with terminals or appropriate quick -disconnects)


but 2-8A charge is OK.

you can use a 10A charger . . . . but i wouldn't leave it unattended and limit it to 1hr use then let the socket cool down.

a 15A charger will most likely blow the supply fuse.

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Note:

lower socket is starter battery.

top socket is leisure battery (if you had the OEM factory second battery option)

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