Understanding Deep cycle/solar charging/how much juice?

[Busiboy]

Ok, Newbie to this electrical stuff, well at a level above installing a stereo anyway

Got the camper trailer ordered adn now I am looking around for batteries etc. The thoughts on power requirements were;

a couple of 8W lights in the tent - 4 hours per night
a small water pump - minimal use
Charging and powering a laptop maybe 1-2 hours per night - I have a DC -DC 12 volt plug for this, not an inverter
maybe also a car radio installed as entertainment (not to be run loud and annoy others though ) 1-2 hours per night

Just trying to work out how much battery use that will require? I was thinking about getting solar panels to recharge it although that appear to be an expensive idea now that I am sort of understanding it. I have a good ole bunnings 800 Watt generator, can this be used for charging for an hour or more a day or will the dirty electricity blow the charger up?

Look forward to the responses

[+dj_hansen+]

The golden rule is P=Vi, power (watts) = V (volts - 13.8 when running, but use 12 for stationary) x i (intensity - amps).

So, as an example of the calculation 2 x 8w lights, 2(8/12) = 1.3a/h

There is a bit more info here http://neuralfibre.com/paul/4wd/batteri ... lated-life

Id set up a simple spreadsheet, 4 columns:

Appliance Watts Hours total amps
Fluros
Fridge
Stereo
Pump
etc
etc
Total Amps Overall

This will give you an idea of how many amps you need in a 24hr period.

Solar panels, as you say are an expensive idea, but make no noise, dont require fuel, etc etc so if you can afford it i reckon are the way to go.

[poppywhite]

your bunnings generator has 12v out for battery charging sould be ok . To plug in other charger 240 - 12v may not do heavy charging @15 or 20amp. the laptop will probally run better from generator they draw more than you think @12v source. 800w dosnt go far.

[ST391GQ]

My general rule for solar is....your maximum load is X..so for solar to be usefull...yu need to go approx. a quarter to a third more in charging capacity..bearing in mind that it is only about 6-8 hours aday that you will get maximum capacity charging. Solar will still charge all day but drops to a trickle as the shadows get longer at each end of day.
And also speaking from experience...solar is a lot more people and environment friendly in almost every camping site over a noisy smelly generator anytime. I have seen more blues started over gensets then I have over solar time after time.
HTH.

Cheers Keith

[Busiboy]

A bit more info for thoughts.

I would typically find myself camped in one spot for a day or two then hook up to the car and head off. I am figuring the car can do some of teh topping up for me if not most/all in most cases, however there is a small situation called cliff hanger where I will be camped in one spot for 5 days straight. The genset won't offend most people there anyways as there is noisy rigs, gensets, compressors and other crap going till midnight so the genny use would be only in a friendly atmosphere.

I figured as well, being the high quality unit it is, I could start it up when we are leaving camp, let it run till it runs out of juice and that should see most of the charging done, figuring I might need to do that once or twice the whole time. The laptop can be largely charged in car anyway, would just be handy to have juice in the tent as well so I don't have to work in the car once I run out of power

Looking as some of the great info above 100-200 AH should get me by easily (100 obviously pushing the love).

Looking at batteries too, the AGM seems to be the way to go, but I don't understand enough about batteries fullstop to know if I am right.

Seems to me that if I want to incorporate solar, it might just be for a top up or maintenance charge. The amount of dough I would need to spend on panels to keep it all running and charged right up would be a fair bit once I factored in regulators adn panels.

[drivesafe]

Hi busiboy, how is your tow vehicle set up, this may help with keeping your camper trailer batteries charged.

[-Scott-]

bearing in mind that it is only about 6-8 hours aday that you will get maximum capacity charging.

The blokes who do this stuff at work (designing solar powered radio comms systems) work on 5 hours per day.

Also remember that the panel needs to be reasonably square to the sun - in southern Australian latitudes, in the middle of winter, a panel lying flat on the roof won't work anywhere near as efficiently as one tilted (40 degrees or so) towards north. Better again if you regularly re-position it throughout the day (such as every time you go to the fridge for a beer... )

[Busiboy]

Hi busiboy, how is your tow vehicle set up, this may help with keeping your camper trailer batteries charged.

Interesting question . . .

Well, the one I am taking for the longer trip, which is the most juice demanding, is set up with a small dual battery setup, don't know many details on that, it was set up for a boat winch and think it might just be parallel. I have to investigate this further.

The other 'tow' vehicle, I shudder to say, is my 40s. Planning on taking this for shorter getaways and I don't think it will be too much of a problem on these trips, If I run anderson plugs and just run them parallel, when towing and disconnect it when camping that should keep everything good.

Got to work out what I need fro teh Bunnings special to charge batteries though, do I need anything flash or just a plug from the 12v to the battery? Or will this blow it up. I am even close to working this stuff out ? lol

[drivesafe]

Hi Busiboy, if you are going to be camping for days at a time and not moving either your camper or your tow vehicle, then you will need some form of additional power, EG a generator, but if you are parking the camper for days or even weeks at a time but using your tow vehicle every day then there is a cheaper and quieter option for keeping your camper trailer battery charged.

You will need an inverter and a battery charger and if you have an auxiliary battery in your tow vehicle, at the end of each days driving, open the bonnet and connect the inverter to the auxiliary battery, then run an ordinary 240vac extension cord over to your camper trailer and plug it into the battery charger, mounted in your CT and leave it on all night.

By morning, you should have pretty well top up your CT battery.

You don’t even need to connect the inverter to the battery under the bonnet, if you are using Anderson plugs to connect between your tow vehicle and your CT, just fit an Anderson plug to the inverter and connect it to the Anderson plug on the rear of your tow vehicle.

This sort of set up can actually reduce the amount of battery capacity you need in your camper trailer.

This set up will give your heaps of power for a fraction of the set up cost of any other option, BUT it does depend on whether you use your tow vehicle while your CT is set up days at a time at a camp site.

[Busiboy]

Drivesafe,

Cheers, I hadn't even thought of that option AWESOME!

[Busiboy]

Seeing as I had already purchased a solar panel though

http://cgi.ebay.com.au/ws/eBayISAPI.dll ... 0179696767

Is this ok for the controller?

I noticed it has a relatively high low voltage cut off though (changable by PC no cable (softwarer?)

The reaszon I like this one over some of the more expensive ones is it is sold as waterproof?