Tow Bar Electrics
Hi can anyone help?
I have been towing caravans for many years and now tow with a 4x4 and a 2011 caravan, for the past many years I have assumed when my car is switched on and attached to the van, the leisure battery is being charged from the alternator in the car. apparently on all new cars and vans this now will not happen and there is no wire from the car to the van to carry the current, the only supply from the car is to the fridge.
If this is correct? how do you charge a low battery if you don't have immediate access to power?
Any comments on this will be greatly appreciated.
Thanks
Roserene
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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/
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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.
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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.
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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
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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?)
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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
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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.
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Don't need to on ours, the stop start switches off automatically when towing, as does the rear parking sensors.
It may be due to the fact we got the manufacturer's wiring electrics (KIA) fitted before we got the car at the dealers, but we made sure to ask for the extra wiring.
The basic wiring is called a 13 Pin Wiring Harness and the extra to charge batteries, fridge, ATC... is called 13 pin wiring supplemental.
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Find another fitter, one who knows and understands what he is talking about. I have a later Santa Fe and it works fine, there is no reason for it no to work fine. I do not know what part of the system would overheat, if you use correct wiring and control unit then they will work fine.
The smart alternator issue can be explained in simple terms by looking at how they operate. The alternator only charges the battery when the engine is in the sweet spot of torque and revs, this means that you are not dragging the load of the alternator at low revs or high load and thus adding emissions and burning excessive fuel. BUT, the charger circuit for the van is only energized when the alternator is on load. The car turns the alternator off, the van charger does not work. The car turns the alternator on and its own battery sucks the current. The van battery only gets the scraps or in some cases never gets switched on. Whilst this can be an issue it is now better understood and can be overcome in virtually all vehicles.
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Probably. We bought a pre registered vehicle, so factory fit towbar was not available, asked the dealer to fit one but they declined, so we had to go to a trailer/towbar place to get the job done. Everything necessary turns off when the van is attached, other than the stop/start.
The instruction to turn it off manually is in the handbook.
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Sorry to cross post and/or intrude, Kjell. Is your 2016 VW equipped with a factory fitted or with an aftermarket towbar, and if the latter, has the canbus been coded to switch the stop/start automatically when the caravan is hitched up? I have a 2016 VW Tiguan and, having paid the VW Dealer for a towbar installation when I bought the car, am being given all sorts of waste product of bovine about it being impossible to code an aftermarket towbar, despite the salesman promising me that it could and would be done! Complaint with VW Customer Care at present so fingers crossed that they will resolve matters.
Steve
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Steve, it has nothing to do with the towbar. It is the way its wired. They have two options to wire the electrics.
1. Tap into the vehicle wiring and use the signals through an aftermarket ECU controller. Perfectly acceptable and done a few of my own cars this way. It is a cheaper option.
2. Use the dedicated wiring (available for aftermarket) and add an OE tow module. This gives the same result but gives added functionality to turn some features on or off as required, it also lets the vehicle know when you are towing and the stability electronics tweaks a few thing to make the towing better. A lot more expensive.
The issue is what was specified for your purchase of the towbar, if they stated OE equipment then stick to your guns. Also ask them to check the voltage between pins 10 and 11 to make sure they fully wired it, as per the OP issue.
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2. Use the dedicated wiring (available for aftermarket) and add an OE tow module. This gives the same result but gives added functionality to turn some features on or off as required, it also lets the vehicle know when you are towing and the stability electronics tweaks a few thing to make the towing better. A lot more expensive.
I think that too much is expected of some cars to automatically switch various things on & off. The towbar on my ML is factory fitted but the reverse sensors on the car require a prod of a digit to turn them off, there is also a trailer setting for suspension/transmission that alters the shift points etc but I've to select it myself.
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Not factory fit as we bought a pre registered Touareg, 4 months old and 14 miles on the clock, but the discount was excellent.
We did ask the dealer to fit a VW approved towbar, but they just were not interested, perhaps they had had a bad experience!
The vehicle does recognise that there is a trailer attached and rear parking sensors are disabled, but not the stop start function. It is not a problem, and the fact the handbook says to turn off the stop start when towing does make me wonder whether that is standard on this model.
The lack of proper caravan battery charging and fridge operation due to the smart alternator was a much bigger problem, now solved by fitting a battery to battery charger in the caravan.
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Sorry, Phishing, my clumsy terminology! I was offered the 'Full functionality of the VW Towbar' and paid for that level of installation. The Trailer Support system works fine, with ABS/ESP et al all doing their uprated functions perfectly, and the fridge charging/permanent live wires being present via the dedicated loom/module.
What's missing is the auto stop/start disabling coding when hitched up. I know from the VW Tiguan Forum that the coding can be changed to carry this out automatically, so I am perplexed that a main VW Dealership cannot do this!
Perhaps they take the view that they outsource the work to Towbar Fitters and can't be bothered to check that all coding changes have been made? Either way, I shall not be doing any further business with the Dealer in question.If VW Customer Care cannot resolve the issue, I shall not be buying a VW when it comes time to replace my Tiguan.
Steve
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. My 2019 Tiguan is able to charge the battery. Why not go somewhere else and have the wiring checked.
