Tow Bar Electrics

Not sure what you mean by ‘new’ cars, but I’m pretty sure my 2016 Hyundai Santa Fe charges the leisure battery when connected. Certainly never had any suspicion it isn’t doing so.

have a read of this.

https://caravanchronicles.com/guides/understanding-the-leisure-battery-charging-circuit/

Some auto manufacturers (usually European) have decided not to include the charging  and fridge circuits in their trailer connectors as this requires a feed from the front to the rear of the vehicle and costs a few more pennies.

As most euro vans do not need or use this feature then they dont bother to wire them, pins 9,10,11. This is in contravention of the published standard that they are obliged to meet, ISO11446.

If you ask for a towbar with 13 pin electrics they just leave them out unless you pay more. Make sure that you ask for it to be wired to the standard above and get it in writing. 

For some reason they think this is acceptable to not meet their obligation or to ask for considerably more money to fit it correctly.

Thank you Ian and Phishing for your comments I do have a 2015 Santa fe and prior to that I had a 2011 Sante fe on which it did not appear a problem, so it could be the fitter is telling me an untruth, according to him all vans and cars of a later age do not have the facility to charge leisure battery due to possible over heating.

Methinks the fitter is talking porkies.  My 2019 Tiguan is able to charge the battery.  Why not go somewhere else and have the wiring checked.

We found that our 2016 VW, despite being correctly wired by the towbar fitters, was not putting much charge into our 2008 model van battery, and possibly not running the fridge, not due to lack of wiring but rather due to the Smart Alternator it has.  It only produces power if the car battery needs it.

One way to help nudge it into action was to always drive with headlights on, but the car still seemed to be taking over and deciding when we should be allowed to have power to the van, even when stopped for lunch.   This meant we often found that when we got to a site, or got home, the battery ran out of steam before we had finished using the mover.

It is a known problem with some newer cars.

In the end, I fitted a battery to battery charger in the van, which has solved all our problems.

Something like this....

https://www.sp-shop.co.uk/Sterling-Power-Wildside-Caravan-Battery-to-Battery-Charger-PN-BBC1225.html

We had the same problem with our first Sportage but when tow bar refitted to our current Sportage the tow bar company "advised" that they now fit some sort of gizmo that fools the alternator into giving more power (not sure if it affects mpg which is the main reason "smart alternators ?" were being introduced?) 

Hi jkeINN

Thank you for the information, I have looked up the site and I do believe it will be the answer, as a matter of interest have you fitted this in your van and if so, is it a straight forward job for someone like me, with moderate ability with electrics?

Thanks

Roserene

Yes, fitted it myself, under the front chest of drawers as it needs to be kept dry.   It was not difficult but you must follow the instructions carefully and exactly, having identified which wiring diagram is appropriate.  Especially regarding fitting fuses.

Electronics/electrics is a bit of a hobby for me.

You need to be able to identify the wires to the fridge and to the battery, and the earth for each.

I have set running the fridge as the priority, the device switches automatically between fridge cooling and battery charging.

You will need some vehicle type wires of a decent thickness to connect everything up, I used "automotive thin wall electrical auto cable", 3.5 sq mm. , and used ring terminals of a suitable size to connect to the unit. 

P.S........If you have "stop/start" on your car, turn it off when towing, the electronics can get confused with all the stopping and starting apparently.

Thank you very much for your information, I will now try and complete the job and have it fitted in time for when the weather turns.