Cheers everyone for the reply's. Our intention is to do mostly off grid camping. Long weekends etc, and maybe a very occasional caravan park holiday. With only a couple of LED lights to run from the 105ah Century battery, I think we can do long weekends fairly comfortably. The gas fridge works a treat too, so off grid should be a walk in the park. If it turns out we are running short of power, I think the option of an external Anderson plug or similar, to plug in a portable solar panel would be a great addition. Still not sure about the Setec ST20 charging specs. It may not be as smart as the ST 20-II, but there is no information that I can see to work out if it does the 14.05v boost (15min every 24hrs) like the ST-II which would be nice. I'm considering buying an appropriate charger to plug in when we get home from a camping, but it may not be necessary.
It seems charging of caravan battery's from a tow vehicle is problematic while travelling, at least without spending $$. But as far as providing a 12v supply from the tow vehicle to run the fridge when travelling, is this worth considering? I have heard that caravan fridges barely hold their own on 12v, but we haven't had any experience ourselves. I have an electrical background, mostly in High Voltage so am enjoying learning about the world of deep cycle battery's and charging systems from you guys.
I have replaced the 240v external power sockets, as they had the weather flaps broken off when we picked the van up, and noticed the quality of wiring installation was pretty ordinary. All fixed now though.
Cheers, Graham
Again
@GrahamHolland , your statements are generally correct., as are
@Drover's. In my opinion and from my own experiences, the Setec is satisfactory for keeping an AGM reasonably charged whilst on grid and maybe okay for some at home. But if I have been away at a caravan park and using the Setec for a few days, I find that when I connect my "smart" charger at home, (battery is 120ah AGM now more than 7 years' old) it immediately starts charging (even if not used since disconnection from grid , and continues until fully charged at 14.7 volts and then switches to Float voltage. I always leave it on for 36 to 48 hours to ensure full saturation and SOC is always 13.0 volts after charging is disconnected for a few hours and remains at 13.0 volts even a week later. The Setec will only give me 12.6 volts under the same conditions. See attached.
I am unable to offer any technical info on your your Setec as it is an earlier model, but perhaps you can contact the makers for data.
If you really want to have full voltage to van fridge when travelling, you have to go the way of
@rags and
@Crusty181 who have BC to DC charging. The only way to go if you wish to spend the money. However, depending on the output of your vehicle's alternator, you can still get acceptable cooling for your 3 way fridge, if you can reduce the voltage drop in the wiring between the vehicle alternator and fridge connection. 6AWG cabling and a separate electrical line connection from alternator direct to the fridge with the use of Anderson plugs is the best way to do it. It does not then go through the Setec and the power diode. There is still a separate wire in the van loom which goes through the Setec and to the van battery for some sort of charging for the van battery albeit not high enough really, whilst travelling.
@mikerezny has a good system and has good cooling to his fridge from his late model Falcon and I can keep things cold and the freezer at minus 18C with my tug. However, you must have some way of disconnecting the fridge line when you stop the engine and one that is fail-proof and does not rely on your memory unless you are good at it!! I have a VSR (voltage sensitive relay) on my tug and it automatically cuts the fridge circuit when voltage drops below 12.6 volts when the engine is not going. It completes the circuit again automatically when voltage exceeds 13.4 volts after start up. More to spend your money on!
However, as
@Drover has mentioned, the 3 way fridge running on 12 volts plus?? from the tug is never enough to pull down the warm contents and should never be used for that purpose or be expected. But if you prepare your fridge well beforehand and fill it with cold/frozen foods, I believe it is well worth having it connected to my tug. Definitely better than using fridge as just a large Esky!! Not a lot to spend, just cabling, Anderson plugs and your time to fit. VSRs and other devices can be added later...usually after you have forgotten to disconnect the fridge and both your van and tug batteries are flat!!! Keep on keeping on!!
