The best laid plans….
We had originally intended to spend a week down at Glastonbury which would have meant the 5 hour drive down would have been an excellent test for the Sterling Power Wildside unit’s first outing. However we had to cancel the trip literally the day before we were due to set off. In the few days between installing the Wildside unit and our planned trip to Glastonbury I had been exchanging emails and phone calls with Charles Sterling talking about some of the aspects of the Wildside unit and the direction that caravan electrics was heading in.
Probably the best route was the one that the Australian caravan community seems to have gone down with a DC to DC charger installed in the vehicle and an Anderson plug to connect between the tow vehicle and caravan or trailer. This allows up to 50 or 60 Amps of charging current and gives them the ability to install 300Ah or 400Ah of battery capacity and be certain of charing it . For us to go much above 120Ah capacity with the current 13 pin setup and to charge it effectively we need to be able to improve the charging current available. I suggested that the fridge might not have to be powered up all the time, maybe on a duty cycle and that would mean all the output would be available to charge the leisure battery. This must have got Charles thinking.
A couple of days later I had a phone call from Charles. ” We can reprogram the box to prioritise the battery or the fridge”. Long story short, I uninstalled the Wildside unit (above) and posted it back to Charles at Sterling Power for reprogramming.
So what’s changed?
The absorption fridges fitted in modern caravans although energy efficiency wise are not very good, they are well insulated and that’s the key point here. The fridge does not have to be powered on all the time. If you go on a ferry crossing, your fridge might be powered down for a couple of hours and most fridges cope. Two hours might be a bit long, but powering down for shorter lengths of time is easily achievable without compromising the performance.
The Wildside unit now has two modes:- Battery Bias Mode (default) or Fridge Bias Mode.
Battery Bias Mode initially charges the battery only for the first 15 minutes or until nearly at full charge. The fridge is then powered up. The fridge remains on then indefinitely providing the leisure battery remains at above a certain level. If the leisure battery voltage drops below, the timer starts again and the battery receives all the Wildside’s output for 15 minutes. This 15 minute cycling continues until the Wildside unit has recharged the leisure battery to a point in the charging profile that dosen’t require a high current.
Fridge Bias Mode operates the fridge permanently with the leisure battery receiving the remainder of the available capacity of the Wildside unit.
Switching between the two modes is as simple as holding down two buttons for ten seconds. If you want to read the full details about how it operates you can find it on the Sterling Power website here
What’s the advantages of Battery Bias Mode?
Looking after the battery is key feature here. You invest in a good quality battery, you may have invested in a multi-stage smart charger to maintain your battery in the off-season or you may have gone the solar route. However plugging the caravan into to the tow vehicle is the same as putting you battery on charge with a cheap 5 amp charger that puts the same energy into a battery whether it needs it or not.
The Wildside unit is a multi-stage smart charger that just happens to be powered by the tow vehicle. Having the Battery Bias Mode allows the unit to recharge the leisure battery as quickly as possible while maintaining the correct charging profile for the battery chemistry and as far as I know it is the only way you could charge different battery chemistry types correctly with a tow vehicle if you have chosen to upgrade from the standard sealed lead acid leisure battery.
So what does this mean for us? Well, it now gives us the option to seriously look at going for AGMII batteries and installing a second battery to increase our capacity to around 200Ah. As we don’t carry two big steel gas cylinders we just have the one lightweight refillable Safefill cylinder we do have the spare weight capacity and space (not in the gas locker obviously!) for a second battery.
I’ll let you know how we get on.
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John Nash said:
After reading several articles on the Sterling Power BBC piece of kit I went ahead and bought one for my 3.0 Amarok, which was new in Dec 2017, to facilitate charging the battery in the caravan and powering the fridge. After much cussing, wiring and re-wiring I could not get it to work so I gave up and decided to check the point of origin of power, which is the 13 pin plug & socket on the car. I was aghast to find that there was no wiring to pins 9 & 10 despite my having specified this along with a factory tow bar in the build for the car. Knowing that the car is euro 6 and is designed with regenerative braking etc. I thought best to leave well alone and seek expert advice. My local VW commercial dealer pointed me to a small factory unit in Stoke on Trent where I was pleased to be given accurate information. A new wiring loom for the 13 pin plug was ordered from VW and subsequently fitted (£250) and my caravan fridge and charging system now work fine. The essence of my story is that with the genuine VW loom the regenerative system is disabled allowing the car to provide power for battery charging and fridge whenever the motor is running without additional items of electronic kit.
Simon Barlow said:
Unfortunately I think you might have been given some mis-information.
When I bought our Amarok Atacama (2016) I did quite a lot of research before asking the dealer to install the tow bar and electrics before delivery. They knew of my intended use and concerns and put me in touch with the people that they normally use. Unfortunately the kit they install did not have VW approval and the VW factory electrics didn’t have fridge and leisure battery circuits. As far as I’m aware VW do not offer any electrical tow bar wiring kits that have the fridge and leisure battery circuits connected for the Amarok as it is classed as a commercial vehicle ( I could not find any listed on their parts system)
I had a number of conversations with the Tech guys at Wolfsburg and at that time the only fully VW approved system was the Westfalia unit, which the dealer had installed by a company that I know and were Westfalia specialists.
On our Amarok, the regen system works and after several thousand miles of driving I can actually feel it on some occasions kicking in. I did verify it was working by installing a temporary volt meter and current meter on the battery. I also had chance to see the results on a VAGCOM unit. There is a LOT of energy being dumped into that battery when it does in a very short amount of time, hence an AGM battery being installed as the starter battery and only ever charged to about 80% capacity in normal running.
The Sterling Power Wildside unit is not really intended to sort out regen issues but Euro6 problems with the ECU shutting down the alternator. Due to the length of the Amarok and cable runs within the caravan, voltage drop on the two power supplies (and returns) is inevitable and coupled with the eco mode smart alternators can cause issues. I’ve seen leisure battery charging circuits only reading 8 volts at the terminals on both the fridge and leisure battery with the engine running which is not enough to charge the battery.
I installed the Sterling Power Wildside unit to basically do two things – first, to provide a stable voltage to power the fridge and second, to make sure the leisure battery was charged correctly with a multi-stage smart charger.
The benefit of the Wildside unit is it can take any excess capacity from the fridge circuit and ‘add’ it to the power required to run the inbuilt DC to DC Multistage smart charger.
I did look at Redarc DC to DC chargers before opting for the Sterling Power unit.
Does your 13 pin socket have a micro-switch in it to let the Amarok know a trailer is connected?
John Nash said:
reading your reply it’s vary apparent that you’ve done a LOT more homework on this than I have and I bow to your superior knowledge.
Yes, my 13 pin socket has the relay built in and I’ve noticed that the car recognises when any trailer is attached.
Following the disappointment and realisation that the euro 6 system and my caravan were not immediately compatible I felt huge relief from my frustration when the chap in Stoke recognised the problem and sorted it with the new trailer wiring loom, so for me this was an immediate solution.
I’m seeing the chap next week, as the 13 pin socket has suffered damage. We have numerous trailers that I pull with the Amarok and constant use has broken one of the retaining clips inside the assembly. I will check as to the source of the wiring loom he fitted and get back to you, although from my discussions with him I was under the impression that it was genuine VW.
Having read your response I may have another go with the Sterling unit, as it’s still in its box unused and although my solution is working, it appears that your solution is working better.
Simon Barlow said:
I was first alerted to the situation towing caravans with the Amarok by some posted on an Amarok forum… which has now ceased sadly (there were a few thousand members from all over the world and the feedback from Australia in particular was very helpful).
I did spend quite a bit of time before we went ahead and pulled the trigger on the Amarok purchase looking at the electrical side of things, including a number of emails to one of Australias larger VW dealers that supply and outfit Amarok’s for the outback community. It was the technicians there that also suggested I look at catch can options as they fit them to new Amarok’s regularly.
There is a growing group on Facebook (VW Amarok Owners UK) which hopefully will become a good resource of info. I’ve uploaded all the VW workshop manuals that are available on line to the group.
John Nash said:
Thanks Simon, I’ll follow that up.
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Ian Rawley said:
Hi Simon, Good work thus far, interesting to see Sterling developing the unit on the fly, they must have moved fairly quickly after you spoke to them as the user manual has already been updated to include fridge or battery bias! I am in Australia and we have an English van, a Bailey Orion. This has an interesting mix of original equipment and extras the Australian arm of the company has added to make the van more appealing to the locals. We love it by the way.
Solar is very popular here for obvious reasons. I would like to mount a panel on the roof of our van and was wondering whether the Wildside BBC unit could be used to also regulate the solar charge to the battery either while the van is in transit (taking some of the load off the alternator) or when set up and disconnected from the tow car. This may entail a manual switch circuit to ‘fool’ the unit into livening up via a voltage on pin 10 even when the vehicle is disconnected. Any thoughts or issues you might foresee with this idea?
Simon Barlow said:
Yes, Sterling Power are very good at being able to react to feedback. It helps that their products are designed with a bit of thought in the first place which does allow flexibility… like being able to upgrade firmware
The Wildside unit is really intended for vehicle to caravan leisure battery charging overcoming the issues we have with Euro 5 and Euro 6 emissions regulation engines coupled with the fact in Europe we have adopted a 13 pin caravan to vehicle connector that does have some limitations.
You guys generally have gone the other way and opted to use a separate charging circuit using Anderson connectors between the vehicle and trailer/caravan with a DC to DC charger. I know this is the preferred method for the 4 x 4 guys that do a lot of outback driving (I’d love to do Cape York or some of telegraph roads) that tow trailer campers like Jase and Simon from All 4 Adventure.
In many respects I think this is a more flexible approach.
For your situation, I’d personally have a look at some of the products that the off road guys have chosen to use as they are well proven for your conditions.
There are a number of companies that have in vehicle/trailer systems that provide total battery management and can charge the leisure batteries from the vehicle, solar or shore power and manage the batteries and usage.
Ian Rawley said:
Hi Simon, thanks for your reply. You are correct they do like their Anderson plugs here and some impressive set ups but there are also a few shonky (local term, I’m a Pom myself!) fit ups and people having fires etc. due to connecting different battery types together with insufficient overload protection! Our van is not really suitable for intrepid trips off road but we do enjoy a few days free camping here and there along the Murray when we can.
The standard Aussie caravan/car interface is a rectangular 12 pin plug standard which can only take a max of 13.5mm2 conductor. This can be made larger if you use Anderson plugs but then you have to start factoring in the extra cost of the large cables/fuses relays isolators plugs etc and the cost of an auto electrical person to wire it all together on the car and on the caravan…it starts to get a bit expensive. Whereas the Wildside unit would appear to be able to utilise existing 2.5mm2 conductors. Do you know yet how many hours you need to drive to recharge say an 80% depleted typical 100A/hr leisure battery using this unit?
On another tack I had a quick google of Sterling Power and it seems they are already in Australia although mostly the marine market. I searched for Wildside and there is a couple of web pages on the Aus site with the comment ‘Coming soon!’ I have left a note to them expressing my interest and what I am wanting to achieve including the solar panel regulation function which would be a good selling point in Aus. If they are looking for a mobile test bed here then I would be happy to get involved!
Madden Broadbent said:
Why install the 12v dc to dc charger in the tow vehicle? We have it as close to the house battery bank as possible using anderson plugs betwee the two vehicles.
Simon Barlow said:
In the UK we don’t use Anderson plugs, just the standard 13 pin towing connector, therefore the limit is around 20 amps.
I have been following this thread with interest and looking for suggestions how to cope off grid. We have often thought of going off grid. Our caravan has a 100w solar panel on it fitted as standard. We have a 25w Avtex TV and a Sky box. The Sky box is rated maximum 45w.
If no Sky box, the 110ah battery on the caravan is able to cope. However with the Sky box it may just last the night or about 5 hours before the alarm triggers. We have a 300w Ring inverter which is about 12 years old for the Sky box.
If we could figure out how to be able to use the Sky box for longer periods, non EHU sites would definitely be an option. We do have a spare 110ah battery however the issue is charging it as we only have the one panel fitted onto the caravan. I know we could always leave the Sky box behind but watching Sky is our form of relaxation in the evening. BTW the caravan is fitted with a satellite dome.
Simon Barlow said:
Running an inverter will always put demands on any battery bank. Maybe updating to a modern inverter would help things out. However I did read about a company that can modify Sky HD boxes to run on a 12 volt supply. Internally it uses the same voltages as a computer apparently. I’ll see if I can find the info again.
Depending on your charge controller, you might have the option to add a portable solar panel that would help.
The other option would be to install a DC to DC charger in the tow vehicle and while you are running about in the tow vehicle charge up your spare battery (installed in a suitable battery box of course) during the day and run two batteries in the evening.
Raymond Bonello said:
I so much look forward to your articles as there is always something to learn. I wish that some time you will discuss the functions of CBE Fuse boxes ie how it involves the circuits of a motorhome and the various uses of these. Had installed on my motorhome DS-304TR 209014. Needs to be replaced and no longer in production. Had a suggestion for 209000. Was told that the proper replacement is 209024R or from another company 215666A. It is a bit confusing.