V70: Electrical Trickle charger

[griston64]

I've just bought a CTEK MXS 5.0 automatic trickle charger for my 2012 V70 D5

One thing I wanted to check is in my cars manual it tells you NEVER to connect any battery charger to the negative terminal on your battery ? Is this nonsense ? Volvo being extra careful ?

The main reason I bought this model is it's simplicity being fully automatic and the video for the charger shows it being connected to both battery terminals in the same way that I would jump start a car

Cheers

[ancient mariner]

Hi.

I have a lower capacity Ctek charger, initially bought for my MX5 for over the winter but I have used it a couple of times so far to top up the battery on my XC70 without problem, and, prior to that the XC90 I had previously. As long as it is a 'digital charger' shouldn't be an issue.

Regards
John

[Tannaton]

It will be absolutely fine, the reason the Volvo recommend that is reducing the risk of sparks when unclipping the charger which could ignite and hydrogen gas lingering that was released from the battery during charging. There’s no risk of this if you follow the CTEK manual and turn off power to the charger before disconnecting it from the battery.

Some models do have battery monitors but if it was in deference of this you would have to clip the positive lead elsewhere.

[griston64]

Originally Posted by Tannaton

It will be absolutely fine, the reason the Volvo recommend that is reducing the risk of sparks when unclipping the charger which could ignite and hydrogen gas lingering that was released from the battery during charging. There’s no risk of this if you follow the CTEK manual and turn off power to the charger before disconnecting it from the battery.

Some models do have battery monitors but if it was in deference of this you would have to clip the positive lead elsewhere.

cheers guys

I thought it would be over zealous health and safety

[SwissXC90]

And the CTEK charger cannot produce sparks when connecting as it doesn't put power on the leads until they are connected to a battery and the charger has detected that the polarity is correct

But When disconnecting, always turn off the CTEK at the mains first, then disconnect from the battery. This ensures also no sparks can be created

Thus you will have zero risk of hydrogen gas explosion if you follow the above.

[RathbranD5]

I have the same ctek charger and a great piece of kit for the last 3 years and been connecting it directly to the battery terminals on my s80 with no issues. Ctek also supply a comfort connect kit with permanent attach leads to the battery terminals for ease of use. Volvo just being over cautious.

[Tatsfield]

+1 on the CTEC charger with the permanent connector. However I was advised on this forum not to connect directly to the battery - terminal as this would bypass the car's charging monitoring system. So I wired the permanent - lead to a strong earthing point on the chassis and the charger still works fine and I'm not compromising any of the car's systems. I keep the CTEK charger under the bonnet and just extend its mains lead to plug it in to the mains to top up the battery when needed, which is very rarely.

[Tannaton]

Originally Posted by Tatsfield

However I was advised on this forum not to connect directly to the battery - terminal as this would bypass the car's charging monitoring system. So I wired the permanent - lead to a strong earthing point on the chassis and the charger still works fine and I'm not compromising any of the car's systems.

I'm not sure about that - my understand is the battery monitor works on the live side of the battery to whether you run the -ve clip to the battery terminal or the chassis makes no difference.

That's my instinct though rather than something I can factually substantiate...

[griston64]

I've connected to both terminals as manual suggests. I'm leaving on as the car now won't be used for a while

Thanks for comments guys

[Tatsfield]

Have a look at this thread which goes into a great deal of detail about battery chargers:

https://www.volvoforums.org.uk/showthread.php?t=260795

I quote page 333 of the Owners Manual for the 2012 XC70;

• The negative terminal on the battery
must never be used to connect a
jumper cable or a battery charger. Only
the ground point on the chassis may be
used.

Rewiring the negative connection for the CTEC permanent connection lead isn't a difficult job, even I could do it, and the manual is quite explicit about the matter. There is a picture here:

https://www.volvoforums.org.uk/attac...1&d=1481987329