I have a 2018 ford focus mk 3 titanium estate. It's the original Varta battery and struggling a bit so I'd like to give it a "repair" charge using a NOCO Genius 5 charger and see whether that's enough to keep it going a bit longer.

Because it's quite awkward to get the battery out I'd prefer to do that with battery in place and the positive terminal disconnected so that the higher than normal voltage doesn't have a chance of damaging the electronics. However the negative terminal is inaccessible so that would still mean reconditioning through the battery monitor. I wouldn't expect that to cause a problem, but am not certain, so can anyone confirm?

Also after disconnecting and reconnecting the battery I believe I shouldn't need a radio code, but are there any other likely complications?
 

14 hours ago, jgh said:

Also after disconnecting and reconnecting the battery I believe I shouldn't need a radio code, but are there any other likely complications?

 

Connect the -ve of your charger to a bare metal body part, like an exposed nut, NOT the battery.(if you connect directly to the battery, you'll bypass the BMS and your car won't know the battery has been charged)  If the battery is disconnected, you may need to re=set the electric windows, but if not, shouldn't be an issue. Your radio doesn't have a code on a Mk3... Charging in situ is standard practice, though I did remove the battery in my car to charge once, but it was 1979 LOL

7 minutes ago, StephenFord said:

Connect the -ve of your charger to a bare metal body part, like an exposed nut, NOT the battery. If the battery is disconnected, you may need to re=set the electric windows, but if not, shouldn't be an issue. Your radio doesn't have a code on a Mk3... Charging in situ is standard practice, though I did remove the battery in my car to charge once, but it was 1979 LOL

Thanks - that is what I was planning to do. My worry is that a recovery charge involves a higher voltage than a standard charge (I think about 16.5v rather than 14.5v) so I wanted to check that this wouldn't damage the battery monitor on the negative terminal as the current would be passing through that.

Thanks for info about disconnecting.

The battery monitor needs a 12V supply so with the positive battery terminal disconnected it won't be operating. I very much doubt the charging current will cause any problems with it. It monitors the current using a shunt resistor which will only produce a very low voltage, likely in the tens of millivolts at the level of charging current.

https://www.bosch-mobility.com/en/solutions/sensors/electronic-battery-sensor/

Just clamp the - side of the charger to the termination bolt of the - lead. Its shaped to allow you to do this. Located on n/s front strut tower.

 

1 hour ago, mjt said:

The battery monitor needs a 12V supply so with the positive battery terminal disconnected it won't be operating. I very much doubt the charging current will cause any problems with it. It monitors the current using a shunt resistor which will only produce a very low voltage, likely in the tens of millivolts at the level of charging current.

https://www.bosch-mobility.com/en/solutions/sensors/electronic-battery-sensor/

This was my thinking also and I think I'll risk it. Whether reconditioning is actually likely to make much difference is another matter of course ..

Thanks all for the reassurance.