S&S battery charging

[Exp21]

Good evening to everyone. Probably it has been asked but I can't find an answer. My w204 CDI MY2012 due to covid has not been used for a month now. I've put the Ctek battery charger to the main battery every about 10 days, but now I have a doubt: do I have to charge also the auxiliary Start&stop battery? Forgive my ignorance about it. And does anyone know if it's better to use the car even for short trips just to use the AC? I know that AC is the thing that suffers the most when circuits and lines aren't used for too many days. Thank you very much!

 

[EmilysDad]

I asked a similar question re the aux battery on my ML & whether it'd charge via the jumper points under the bonnet ..... the answer seemed to be that it doesn't. However, re the main battery, just connect your CTek to the main battery & leave it, that's what I do with my Smart Roadster & never had a problem.

 

[Exp21]

Thank you! So I have to charge even the aux battery!! Tomorrow I'll try!

 

[Kev555]

probably once a month for 10-20 mins would be enough to run the car with AC turned on to keep it from losing gas. Some other members that store similar cars would know best intervals to run the car to keep AC right. I cant answer about Aux battery as I dont know if its linked to the main battery.

 

[Exp21]

Thank you very much. Generally on cars' manuals I read things as "use the AC for at least 15-20 minutes a month" if I remember right. I'll use the car for a short trip just to avoid the risk

 

[EmilysDad]

a very clever mate says that the aux battery is comparable to a caravan leisure battery and can withstand being discharged

 

[Exp21]

Ok! So I can avoid charging it. We made it clear at last. Thanks mate, really

 

[Tony Dyson]

a very clever mate says that the aux battery is comparable to a caravan leisure battery and can withstand being discharged

I'm sorry to throw a spanner in the works here but I have to disagree with ED's mate on this one, no matter what type of Lead Acid battery you have, i.e. Flooded, AGM or Gel, any extended period of discharge for any Lead Acid battery will result in a degraded performance and at a discharge state of 10.5v or less, the damage is very likely to be permanent. I think you'll find that the Aux battery will be charged when there is an output from the car's alternator so you would need the engine running for this unless of course you attached your charger directly to the batt terminals.

 

[EmilysDad]

I'm sorry to throw a spanner in the works here but I have to disagree with ED's mate on this one, no matter what type of Lead Acid battery you have, i.e. Flooded, AGM or Gel, any extended period of discharge for any Lead Acid battery will result in a degraded performance and ......

Agreed .... maybe I should have said they're 'better able' to be fully discharged

 

[Exp21]

Thanks, to avoid any damage to AC I decided to use the car for 10-20 minutes. So I will see if ECO becomes green. If it stays yellow I'll put under charging also the aux battery