EMOVE Motor Mover stopped work, but works perfectly again (apparently)

[djdd]

As an aside, I saw I can view all my battery stats on the Swift Command portal, so judging by this (12..8v during the middle of the night going to 13-14v during the day), I think the current battery is perfectly healthy. My money's on the smart alternator. The towbar company have said I can pop over whenever to double check the switched relay.

 

[Jcloughie]

One possibility that I've had personal experience of and many others if you search across the web.....though none on this forum......is that modern cars with Smart Alternators can discharge caravan batteries.

This is what happened to me. Old car towed caravan no problems. Newer car with Smart Alternator, same caravan, got home, engaged mover and it went a few centimetres then stopped.

After some investigation it happens on my Nissan that when the Alternator goes into Smart mode the output is reduced and the cars electrics are powered by the car battery until the Alternator kicks in again.

Due to lack of foresight on Nisssans part and possibly the towing kit manufacturer, this also means that the caravan battery will also feed the car but won't get properly charged when traveling.

The other symptom is that the fridge doesn't get enough power to be kept running all the time when towing.

So on my first trip, no working mover. Hooked up to EHU and at end of stay mover ok. Got home mover not working.

So it's possible that when you took your caravan back to the dealer the solar panel had charged the battery just enough for a quick test to show the mover motors spinning.

I am told, but I do not know exactly how! That a diode can be fitted in the charging circuit from the car. This would allow charging if there is sufficient potential, but prevent the caravan battery from draining back.

Perhaps something is available commercially.

John

PS. Just Googled it, seems you need a low voltage, DC to DC charger fitted in the circuit.

See this for much more info..

Smart Alternators: how they affect Caravans and Motorhomes….

I have been receiving a lot of emails over the last two or three months from people reporting issues around charging their leisure batteries after changing tow vehicles and a similar number from pe…

caravanchronicles.com

 

[ProfJohnL]

One possibility that I've had personal experience of and many others if you search across the web.....though none on this forum......is that modern cars with Smart Alternators can discharge caravan batteries.
...

Sorry Sam this might seem pedantic, but technically the alternator does not discharge the caravan battery. It's the way the alternator works (or turns off) might cause the caravan battery to discharge, but the actual battery discharge current does not flow through the alternator so it is not the device that's discharging the battery.

The way the caravan is connected , and the alternators control software that should be addressed.

 

[Jcloughie]

Sorry Sam this might seem pedantic, but technically the alternator does not discharge the caravan battery. It's the way the alternator works (or turns off) might cause the caravan battery to discharge, but the actual battery discharge current does not flow through the alternator so it is not the device that's discharging the battery.

The way the caravan is connected , and the alternators control software that should be addressed.

I took it that it is not actually the alternator that is doing the discharge, but the alternator switching off to save fuel, allowing the car to run off the battery, But the car is also running off the van battery.

More info on the link in my previous post.

John

 

[Dustydog]

Clearly something is very wrong in the circuit if the caravan battery is running the car!

Decades ago we had a split charger relay . It only switched on when the engine alternator was running. Engine off ,no power from alternator it switched off.

My VW is fitted with an approved wiring kit, professionally fitted which goes well beyond the old split charger relay. In fact the engineer changed a number of ECU settings with his laptop per VW and Westphalia guidelines. Never had a problem as described . I have auto switch off/on which is always active.

The latest Smart Combi relays fitted to my VW are switched on and off by an internal voltage-sensing system that senses when the vehicle's alternator is charging the vehicle battery.
I am told by my Tow bar expert mine is totally fail safe. Simply , no matter what happens with engine off , over run etc, the caravan battery cannot connect and drain via the car.
Seems to me the situation described is the fault of

a poor installation,
incorrect or failed Smart relays
failure to correctly re set the main car ECU per the manufacturer’s guide.

 

[Sam Vimes]

Sorry Sam this might seem pedantic, but technically the alternator does not discharge the caravan battery. It's the way the alternator works (or turns off) might cause the caravan battery to discharge, but the actual battery discharge current does not flow through the alternator so it is not the device that's discharging the battery.

The way the caravan is connected , and the alternators control software that should be addressed.

Being doubly pedantic you'll note that I said 'cars fitted with smart alternators' not that it was the alternator itself causing the discharge.

The inclusion of a diode could indeed prevent reverse current but you'd need to choose wisely. There can be a considerable voltage drop from the car to the fridge for example and the wrong type of diode wouldn't help this.

Dc to Dc Converters can fix the problems including the fridge dropping out. But for me the keep it simple approach was to disconnect the battery.

Clearly something is very wrong in the circuit if the caravan battery is running the car!

Decades ago we had a split charger relay . It only switched on when the engine alternator was running. Engine off ,no power from alternator it switched off.

My VW is fitted with an approved wiring kit, professionally fitted which goes well beyond the old split charger relay. In fact the engineer changed a number of ECU settings with his laptop per VW and Westphalia guidelines. Never had a problem as described . I have auto switch off/on which is always active.

The latest Smart Combi relays fitted to my VW are switched on and off by an internal voltage-sensing system that senses when the vehicle's alternator is charging the vehicle battery.
I am told by my Tow bar expert mine is totally fail safe. Simply , no matter what happens with engine off , over run etc, the caravan battery cannot connect and drain via the car.
Seems to me the situation described is the fault of

a poor installation,
incorrect or failed Smart relays
failure to correctly re set the main car ECU per the manufacturer’s guide.

Really none if the above.

My wiring harness is a dedicated rig not a general purpose one.

The problem is a disconnect between the car designers, tow bar wiring designers and caravan designers. None if which want to step up and fix the underlying problem.

My car knows there is a caravan/ trailer attached.

The wiring harness uses the Canbus to communicate.

There is no ECU update from Nissan in respect of towing.

The wiring in the caravan isn't really up to the job.

 

[Seblo]

Some 12v systems with solar are not designed to be run without a battery. Check with your owners handbook first.

 

[Dustydog]

Being doubly pedantic you'll note that I said 'cars fitted with smart alternators' not that it was the alternator itself causing the discharge.

The inclusion of a diode could indeed prevent reverse current but you'd need to choose wisely. There can be a considerable voltage drop from the car to the fridge for example and the wrong type of diode wouldn't help this.

Dc to Dc Converters can fix the problems including the fridge dropping out. But for me the keep it simple approach was to disconnect the battery.

Really none if the above.

My wiring harness is a dedicated rig not a general purpose one.

The problem is a disconnect between the car designers, tow bar wiring designers and caravan designers. None if which want to step up and fix the underlying problem.

My car knows there is a caravan/ trailer attached.

The wiring harness uses the Canbus to communicate.

There is no ECU update from Nissan in respect of towing.

The wiring in the caravan isn't really up to the job.

You’d expect a dedicated one to be fool proof! Poor show Nissan🤬

 

[Sam Vimes]

You’d expect a dedicated one to be fool proof! Poor show Nissan🤬

Yes, Smart Alternator systems have been around for a while and some cars do a better job in respect of towing caravans.

 

[Buckman]

Yes, Smart Alternator systems have been around for a while and some cars do a better job in respect of towing caravans.

When we had the towbar fitted on the Jeep I was asked whether we wanted the facility to keep the fridge cool while travelling. I declined as in the past we had hardly ever used the facility finding that ice blocks kept the fridge cooler.

 

[trevormonty]

Now that solar panel is operational, next step is to add 12v socket that has low voltage cutout set it to 12.2V (50%) and connect fridge to it while travelling. Without sun should give 4-5hrs run time, on sunny day a few more hours. Lot cheaper option adding extra circuit to car wiring.

This 12v outlet will also be used for charging bike battery when using unpowered sites.

 

[Buckman]

Now that solar panel is operational, next step is to add 12v socket that has low voltage cutout set it to 12.2V (50%) and connect fridge to it while travelling. Without sun should give 4-5hrs run time, on sunny day a few more hours. Lot cheaper option adding extra circuit to car wiring.

This 12v outlet will also be used for charging bike battery when using unpowered sites.

I have probably misunderstood you, but the fridge will not work on 12v unless connected to the car with the engine running.

 

[ProfJohnL]

Caravan ridges typically require about 100W of power to run at 12V that draws about 8.5A. A 100W or larger solar panel could supply enough power to run the fridge, provided it has enough light.

In practice when towing, It's very unlikely the solar panel will get enough light to maintain its full output, but it probably won't be enough to keep the fridge safely cold.

Direct connection of a caravan fridge to the leisure battery will put a considerable constant load that will discharge the battery fairly quickly, and that is likely to compromise the working of a caravan mover if you have one fitted.

I suggest having the cars 12V supplementary supply wired will be a better long-term solution.

 

[trevormonty]

I have probably misunderstood you, but the fridge will not work on 12v unless connected to the car with the engine running.

Fridge doesn't care where 12V comes from. Typically fridge 12v circuit isn't connected to house battery as it would flatten it over 8 hours. For travelling it is wired to separate circuit that comes from car ignition circuit.
Power is only supplied while cars ignition is on.

Most cars won't have this circuit wired to towing socket and in lot of cases caravans won't have it wired to their towing plug. Given extra cost of having it wired up at both ends most caravan owners decide to go without.

 

[trevormonty]

Caravan ridges typically require about 100W of power to run at 12V that draws about 8.5A. A 100W or larger solar panel could supply enough power to run the fridge, provided it has enough light.

In practice when towing, It's very unlikely the solar panel will get enough light to maintain its full output, but it probably won't be enough to keep the fridge safely cold.

Direct connection of a caravan fridge to the leisure battery will put a considerable constant load that will discharge the battery fairly quickly, and that is likely to compromise the working of a caravan mover if you have one fitted.

I suggest having the cars 12V supplementary supply wired will be a better long-term solution.

Adding low voltage cutout protects house battery. In my case I'll set it to 12.2V or 50%. Without sun should get about 5 hours of cooling (120W circuit 100Ahr battery) expect few extra hours on sunny day.

 

[Sam Vimes]

Fridge doesn't care where 12V comes from. Typically fridge 12v circuit isn't connected to house battery as it would flatten it over 8 hours. For travelling it is wired to separate circuit that comes from car ignition circuit.
Power is only supplied while cars ignition is on.

Most cars won't have this circuit wired to towing socket and in lot of cases caravans won't have it wired to their towing plug. Given extra cost of having it wired up at both ends most caravan owners decide to go without.

I'm not sure what you really mean by house battery but assume that this is the NZ term for what in the UK is called a leisure battery.....the one in the caravan.

Here in the UK at least, fridges can run solely on 12v. This is a considerable load on the battery but depending on battery capacity could run for several hours before it needs recharging.

Later fridge models do require 12v for the control panel even if not using the 12v for cooling.

Again tow bar fitters here usually ask if you will be towing a caravan and do you want the fridge to be powered when towing. The answer determines the type of wiring harness.

Caravans I've come across in the last 20/30 years have the fridge wired to the towing connector for this purpose.

 

[trevormonty]

In NZ its rare to have extra circuit wired on car. Then again most cars never tow a caravan let alone UK one with fridge. More often than not it would be boat, or trailer.

I'll have to check wiring on my 2000 Bailey used import, but don't remember Aux circuit being used on towing connector when I replaced damaged 7pin. NZ and Australia use 7pin connector for towing. Standard wiring is Lights, Indicators, Brake. Reverse and Aux not normally connected on car socket. Imported caravans will have round UK plug replaced with this 7pin.
There is rectanglar 12pin avaliable for extra circuits like electric brakes. Some car owners still use round UK socket. In both cases car owner would want to have an adaptor cable as all hire trailers and most boats will have 7pin.

 

[ProfJohnL]

With a fully charged 100Ah battery in good condition in it should be capable of supplying 1 Amp continuously for 100 hours. The theory suggests it will mange 2A for 50 hours and so on arriving at 8A for 12.5 hours, but unfortunately it's not that linear.

The bigger the current you draw, the batteries ability to sustain that current diminishes faster than the linear progression suggests. At 8Amps I suspect most 100Ah leisure batteries would manage at best might manage 6 hours and if the battery is getting old it might drop as low as 4 hours to fully discharged.

If you use a 12.2V low battery (half charge) limit the times above might be halved.

I don't know if caravan manufacturers who export to NZ adapt their products to NZ standards (the should ) but if not, the UK main 7N pin connector only carries the road lighting .

There used to be a 7S supplementary connector which carried battery charge and fridge circuits

 

[RogerL]

I thought that campers and caravanners in Australia and New Zealand preferred compressor fridges, rather than the absorption fridges we're used to in UK/Europe - with the aid of a solar panel and battery, a compressor fridge will function well in their climate without the need to run from the engine charging circuit.

 

[ProfJohnL]

I thought that campers and caravanners in Australia and New Zealand preferred compressor fridges, rather than the absorption fridges we're used to in UK/Europe - with the aid of a solar panel and battery, a compressor fridge will function well in their climate without the need to run from the engine charging circuit.

That might be true, but on an used imported UK model it will most likely be an absorption fridge.

 

[trevormonty]

That might be true, but on an used imported UK model it will most likely be an absorption fridge.

UK caravans are 3way absorption. New offroad Australian type vans, can be either depends what original owner wanted. For the Australian outback compressor work better in heat but requirer large solar+battery system. For NZ temperatures 3way are fine most of the time.