New Camper

Johnny R
I think you want the batteries to be good Boys, not bad ones. Firstly, were the batteries fully charged beforehand?
Depending on the ambient temp and fridge/freezer setting, the freezer aspect will use plenty of amperage hours. If you don’t know what the running current draw of the fridge actually is then it is hard to work out expected time use before considering the other devices you also use.
You said the ampage is around 10, I presume you mean amperage of 10 amps and at that constant drain, the 3 batteries will last about 30 hours and will be fully depleted to below a safe level for long life.
Although you have a solar panel it must be able to provide reasonable amp output through the regulator to even attempt some recovery while the sun shines.
A 100 watt solar panel will never give 100 watts in real life and it’s output will be around 6 amps in really good sun conditions. If yours is like this then it is just dribbling a bit of power, not much at all, into the batteries and will not keep up with the drain of amp/hours in a 24 hour period.

What shouldn’t voltage not run under? Should I invest in a generator?

Best John

One of the electro-gurus might be along soon (I'm not one), but an observation or three of mine might be of use until then....(I fritzed my first set of 3 x deep cycles in my van, due to neglect...been trying to make electrons my best friends ever since :-).
Presuming you have deep cycle batteries of some quality ($$$)...
1. Monitor their voltage when they are working (NOT when idle...batteries that are idle can show 12 volts +, but soon plummet when a device starts up)...your best indication might be when the fridge is running.
2. Don't let their voltage get below 12 at any stage ! To do so shortens their lifespan significantly. In round terms, a well charged deep cycle gets down to 12.8 (+or-) quite soon, but then does all of it's good work as it slowly depletes to 12 volts.
3. Ensure that any regulators used are set for your battery type (you need a suitable regulator too of course... for whatever charge method you employ).
4. To save your batteries when they approach 12 volts, you have no option but to start charging. Some solar is ok, more solar is better (portables can often be best for catching the sun early and late in the day), but...if you can't get the sun you have to generate power ! Using the car \'s alternator via the hitch plug might get you by, but my preferred method is via my 1kw pure sinewave generator that I carry for the purpose.
Oh...and....just as the sun doesn't always shine for the solar panels, generators often can't be used too (noise pollution for other campers and or park regulations etc.).
Summary ? Keep them charged right up as much as you can for as long as you can and never go below 12 volts.
Good luck with it.

Johnny, if you drop below 50% state of charge you will shorten the life of the batteries. Also I'd suggest you get a battery monitor to keep an eye on things.

I have a 95 litre Evakool set on LOW ECON and it keeps stuff cool or frozen as the case may be. I run it off a 200 watt solar and an 85AH battery and still have to run the engine at a very fast idle from time to time if it's cloudy for more than a day or two.

After checking the capacity of your alternator and Anderson plug wiring, you might consider a 60 amp DC-DC charger. Sterling Australia has one. Also some more solar would make sense. Nobody likes to be camped next to anyone with a genny.

Keith

Hi Johnny R, Let me say at the outset, I am not an electrician, nor am I an expert on all things 12 volt, however I have been camping in the Bush for many years. We mostly free camp away from any 240 volt power source. There has been some good advice given in replies to your post already, the best being to check the blog section on the forum regarding 12 volt systems.

My current set up is an Off Road caravan with 2 x 150 Ah deep cycle batteries, 2 x 200 Watt roof mounted solar panels, the van has a 190 Ltr compressor fridge. This normally keeps me going for up to a week in 35+ degree heat, with good sunlight. I also carry 2 x 120 Watt folding solar panels for when the sun doesn’t shine as much. So far this has seen me through most times, wth one exception, when we also had to use the car for an hour both morning & night to top up, we had three days in a row of rain.

Unless I missed something, you did not say what size your solar panel was, but I would suggest that 5 days with your current set up is pretty good. Of course there are a few factors that have an influence on how long your batteries will last. Ambient temperature, how many times you open the fridge, fridge not in direct sunlight etc.

Before spending big money on a generator that you may not be able to use, depending on where you are camped, I would be looking at more solar panels. The Solar Blankets will give you “more bang for your buck” with regard to output, take up less space when folded, but the good ones are expensive. Traditional folding type can be used to “chase the sun” by moving them every hour or so to get the best angle to the sun, and you can get 160 Watt panels these days. However, they take up a bit of room when travelling.

If you really want to be self sufficient with regard to 12 volt power, solar panels in conjunction with a generator when it can be used would be the ideal set up. IMHO, for your current set up, I would have at least 300 Watts of Solar, before getting a generator. Particularly if money is an issue.

Macca.

If your Evakool is one of the RF fibreglass models then -12 degrees for the freezer works well. Sometimes liquids close to the fridge divider start to get ice in them after a day or so. Mine is 82l. Also, in higher ambient temperatures of mid 30's plus mine runs almost continuously, particularly when the drawer is closed and airflow restricted.

As others have already said, you need more solar for that amount of battery. I have 400w of solar for 330ah of battery and that seems about right for my use.

Hi Jonny,
You have some good replies already.

Is the fridge a white fibreglass unit with the compressor on the end. I have this type in the 85lt size and run it at -15 temp and medium setting with the divider in the centre so I have freezer and fridge arrangement.

Make sure you have good size cable from the car to the trailer via the Andersen plug to the trailer to avoid voltage drop.

Do you have a dc-dc charger in the trailer or is it just the alternator charging via the starter battery. For 3 batteries at least a 40 amp charger minimum ( if batteries 50% flat then150 amps needs to go in, so a 4hour drive with a 40 amp charger) If it’s only 25 a charger then you would need to drive all day to recover 3 flat batteries.

What is the tow vehicle as this will indicate charge voltage and alternator output.

Hi Guys,

Stupid question but if I add a solar blanket to my 160w how do I connect both together, ie can I use an Anderson splitter?