Caravan Movers

[RayS]

While in Spain recently I saw several instances of people with Carver movers using them with the mains cable still connected. leaving aside for the moment the possible safety implications, I am surprised that this does not damage the on-board charger which is certainly not intended to deliver such high currents as a mover will take, particularly in the loose gravel / incline circumstances pertaining. One user said his dealer had told him to do it this way.

Any technical comments please.

 

[Damian]

Ray, the main concern would be the safety of the mains cable, and possible snagging, or running it over and ripping it from the van. As for the mover, it draws the power from the battery, so theoretically the charger issue does not come into play, as it will only push out to its set max, if that much.I do not think it would do the battery much good though, if it being rapidly discharged AND charged at the same time.

I would have grave doubts about whichever dealer advised this course of action!!

 

[ProfJohnL]

Hello Ray, It is definitely NOT RECOMMENDED to have any lead connected to the caravan whilst using a mover

- especially 230V mains as it is possible that the cable would be damaged and the fault may result in the caravan becoming live.

Note for Damian: you are correct in that a mover properly installed would be connected directly to the battery. If the charger was on, then the battery would not be upset, as the charger would be adding to the available current for the mover. though in practice the battery would still supply the bulk of the required current.

 

[RayS]

Hello Ray, It is definitely NOT RECOMMENDED to have any lead connected to the caravan whilst using a mover

- especially 230V mains as it is possible that the cable would be damaged and the fault may result in the caravan becoming live.

Note for Damian: you are correct in that a mover properly installed would be connected directly to the battery. If the charger was on, then the battery would not be upset, as the charger would be adding to the available current for the mover. though in practice the battery would still supply the bulk of the required current.

John, are you saying that the charger is current limited, so no harm will come to it by this practice ? I suspect it might be but did not want to make a potentially very expensive experiment.

Agree with you totally about the safety aspects, but one situation arosee with the mover battery flat and frozen and very very difficult to get the van off site without it - involved tow rope through the feet of the (retracted) rear legs. Unfortunately only other people about were in the same class of infirmity as I am and pushing 1550Kg is really not on. Ray

 

[ProfJohnL]

John, are you saying that the charger is current limited, so no harm will come to it by this practice ? I suspect it might be but did not want to make a potentially very expensive experiment.

Agree with you totally about the safety aspects, but one situation arosee with the mover battery flat and frozen and very very difficult to get the van off site without it - involved tow rope through the feet of the (retracted) rear legs. Unfortunately only other people about were in the same class of infirmity as I am and pushing 1550Kg is really not on. Ray

Hello again Ray,

All battery chargers and caravan power supplies by their nature will only produce a limited amount of current. Exactly how much and how they will react under load is down to details design issues. Most properly designed systems will incorporate current limiting devises, either electronic foldback, or may be as simple as a fuse.

For a battery to be charged, the charger/powersupply must have a terminal voltage that is greater than the battery, so charge can be "pushed" in. If the charger voltage falls below the battery voltage then no "charge" can be pushed in. Under load conditions such as a mover, the current will be preferentially taken from the charger until its terminal voltage matches the battery at which point the battery will start to supply current.