AlexandriaUK said:
I think I need to go on an understanding USB socket course LOL so if I'm right in my understanding if I fit a USB socket direct to the battery I need A an inline fuse and B an on off switch to make sure I don't flatten the battery.
Or will it be such a small amount of charge taken the solar panel will be sufficient to cover the small loss
Hello Alexandria,
I realise the point I was trying to make in my last post was not really clear. A previous poster had just suggested fitting the USB connectors, and providing they are good quality ones, the standby current they use will be very small, and certainly less than the caravan alarm system, so for most people nothing to be concerned about. But some of the poorer designed usb adaptors may have bigger stand by current, still not massive, but because their on all the time, what they use, does accumulate into a more significant amount.
If you want to caravan "of grid" then you need to be able to stop all unused appliances and fittings like USB sockets from unnecessary power usage to maximise battery life, so having the ability to switch off such devices may be important.
From an engineering point of view, it is simply good practice to be able to isolate every power consuming device, even if it is as small as a usb adaptor, if for nothing else to enablecircuit testing and fault finding.
If you are using a solar panel, then that will easily offset the power demands of the usb adaptors, so no worries there.
Even 12v wiring has the potential to cause a fire if a short circuit fault arises, so proper circuit protection such as fuses is a definite yes.