Going to put the main battery on a Ctek - do I also need to do this for the aux battery or will this be charged from the main battery?

I charge mine with a ctek and I assume it does the auxiliary battery too as the start stop works when the battery is fully charged and I believe the auxiliary battery supplies this (I could be wrong)

Over the last week when we had the cold spell in the UK, I connected mine to a Ctek conditioner for about 1 week - seems to have transformed the car - stop / start works more effectively, no longer a strain to start at crank up. I connected the CTEK to the terminals in the engine bay so assume its conditioned all the batteries.

Prashan MY16, 3.0D HSE Dynamic, Barola Black, TV, Rear Entertainment, Opening Pan Roof, Meridian

Yep I do the same using under bonnet terminals

Can’t say I’ve ever had a problem even with working from home for a year. Most journeys have been a mike to the supermarket, but then I go the long way home, about 7 Miles/20 mins, once a week and never had a problem Joined the X5 45e club
1994 Defender 90 300 tdi

I think if charger the main batery either from terminals under bonnet or directly the aux batteyr wont get charged up. The aux battery is topped up when the engine is running an the main battery has reached a level that the BMS (battery management System) is happy with then it nye passes the main and start to charger the aux, form what ive been told. its possible that both get charged when the engine is running but more charge power goes to the main.

Charging the battery with the engine is off will mean the BMS or systems are not running so an of that jiggery pokery the BMS does wont happen so I think only the main will be charged up.

I susspose that as long as the main has a full charge then next time you go for a bit of a drive the little guy will get charged amlost straight away as them main wont need mouch to top it back up. Just disable ASS whilst this is happening as you dont want to get it to the point it has enoigh charger for ASS to start work and then deplete again quickly. If a jobs worth doing, get a someone who knows what they are doing to do it!

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