Saturday, Mar 28, 2009 at 22:45
Kim and DD,
Before I start I will say that 12 volt electical wiring for 4WD and campers can be a hot topic and some have very strong ideas on what works and what doesn't. If any type of heated debate follows, I'm outta here......... PM me if you wish any further opinion. Here's my further take on your questions........
XS2500 would be the best, but you could get away with the XS1500 depending upon how quickly you needed to charge your batteries and how flat you intend to let them get. If running this off a generator, I imagine you will want to limiti the genset run-time, so a higher capacity charger would be best and probably worth the extra $$ for you.
I never carry a generator and only occasionally go to caravan parks, so rely on the car to charge the camper and car aux batteries (total 240AH). I have the capacity to stay in one spot for about 3 days with the one fridge and a few lights and running the
HF radio a little, depending upon weather and not discharging everything down to the barest minimum, say about 50%. I also don't have any solar panels as yet.....though when the budget allows..... :-(
Gas fridge much better proposition if staying put for any length of time without adequate solar supply.
In regards to the wiring from the second battery to the Anderson plug, this is my take on it....
Cable sizes and terminology is a bit of a minefield, not worth getting bogged down in. Forget the amp capacity as it's really irrelevant in our situation. The best way to understand it is to think about voltage drop. Basically the more current (amps) carried by a cable length and the longer it is, the greater will be the voltage drop.....(hence long distance electricity transmission lines run at 330,000 volts!!!)
Firstly, you need to figure out how much emphasis you wish to put on the capacity of the car alternator to charge both the camper and car aux battery. If you will be relying on this PRIMARILY to charge this battery from a relatively flat (say 50%) state, then your wiring will need to be top notch, with heavy duty cables, good quality connections and Anderson Plugs, so that the batteries receive a decent charge voltage and it will still take some hours of driving to charge the amp-hour capacity of batteries you have. Those that tell you to just plonk 6mm cable there and don't get carried away....blah blah... haven't REALLY studied the effect of voltage drop over cable length and the effect on battery charging. So just get the heaviest cable you can afford to, plus 2 x 175 amp Anderson Plugs (you will need these big mothers to fit the larger cables in) appropriate terminals and a circuit breaker or maxi-fuse for protection.
On the other hand if you are going to be spending most of your time
camping where there is access to 240v power (or generator with charger) and you are happy for the batteries to be recharged PRIMARILY via this method, I wouldn't worry about spending so much time and money arranging a heavy duty charging system from the alternator. Just stick thinner cable there and accept the voltage drop. The batteries will charge, but never very
well, never fully and whatever charge gets to the batteries will take a very long time. That's the trade-off. It's horses for courses.
I hope I haven't confused you more. Feel free to pop around to Edithvale and have a gander at how I've set up
mine if you wish or PM me for further if you would like.....
Cheers,
Mark
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