battery charging

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battery charging

Postby dea » Thu Sep 17, 2009 7:49 pm

ok just a few questions ...


when using a battery for camping.. how do you charge it when it goes flat ..

we will be using it for fridge freezer & lights ... this is not going to last long.. so how do we charge it .. its the deep cycle battery will be all wired up in the CT ... so not using the car battery ...

tell me what is the best to use
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Re: battery charging

Postby GypsyLady » Thu Sep 17, 2009 9:02 pm

Now you are getting into some pretty serious stuff dea.

Either solar or generator are the usual ways in the bush for recharging the battery dea. If you have it running through a 3 stage charger then you can hook to 240 if you are in a CP or somewhere that has 240 available.

Do not discharge it totally, DC batteries should never be discharged below about 60%.

Also best to use a 3 stage charger for the generator, in fact the only way to fully charge a DC batter is with a 3 stage charger...also called 'smart' chargers as well.

You will not fully charge a DC battery with the alternator on the car so don't let anyone try and convince you that you can.

For charging with solar you will need a regulator.

Not sure what you are expecting to run with the DC battery but if it is only low watt lights then you should be fine for a few days without having to recharge the battery.

If you are considering running the fridge then that is a whole different ball park. Another thing you should know is that 3 way fridges do not run well on 12volt, it is more maitenance mode. Gas and 240 are the best for 3 way fridges.

Now solar you can use anywhere but it is costly to set up especially if you plan to use your fridge with a freezer option. You only need a couple of inclement days to put you behind the eight ball with solar.

With generators.....there are lots of places that will not allow generators, NPs for one so keep that in mind.

In saying all of this though I must say I have both so that all my bases are covered but I have also been camping for many, many years and it has taken a long time to get as well set up as I am.

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Re: battery charging

Postby dea » Thu Sep 17, 2009 10:14 pm

its all so confusing .. my main thing is how do we run this fridge for 7 odd days while out bush camping with power etc ... lights are fine they dont take much .. but the fridge will..

im so confused
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Re: battery charging

Postby Blue Bravo » Thu Sep 17, 2009 10:39 pm

If the second battery is in the camper then you will have to have an external method of charging unless you want to run the car for several hours a day to keep the second battery charged. Otherwise the battery will last for 2-3 days. As Gypsy says then you have to decide between solar or generator. Solar is pretty expensive to set up but costs nothing to run and can be used in National Parks and crowded camp areas. A genrator can be anything from a couple of hundred to a couple of thousand. You could run the fridge direct from the generator but this means it would have to run for extended periods. With both systems you are charging the battery which then powers the appliances. Most national parks ban generators.
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Re: battery charging

Postby Derek Bullock » Thu Sep 17, 2009 10:48 pm

One of these would be ideal for you http://cgi.ebay.com.au/100W-FOLDING-SOL ... 286.c0.m14
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Re: battery charging

Postby tezzaglen » Fri Sep 18, 2009 12:32 am

christie engineering make a petrol powered battery charger for around $990 it uses an alternator to charge the battery
the same way your car does

http://www.christieengineering.com.au

regards

tezza
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Re: battery charging

Postby GoldCoast » Fri Sep 18, 2009 12:48 am

dea wrote:its all so confusing .. my main thing is how do we run this fridge for 7 odd days while out bush camping with power etc ... lights are fine they dont take much .. but the fridge will..

im so confused

The lights will use next to nothing compared to the fridge.

Here a some rough calculations to give you an idea of the issues.

The amount of power required for the fridge/freezer will depend on the duty cycle.
For may fridges (like the one I just bought) you would expect them to be running 100% on 12V and still struggle to keep things cool. Fortunately they have a gas option.

Your fridge has good insulation and being electric only is probably a lot more efficient than a three way absorption type so if it wasn't opened much you might be lucky and have it run a lot less than 100% of the time.

I'd suggest calculating for continuous running and adjust proportionally from that.

Assuming the worst case of continuous running it would require 5 amps for 24 hours or 120 ah per day. (or 840 ah for the whole week)

Your battery capacity would need to be much greater than this to avoid shortening their life and reducing their capacity by discharging them too far.

We are now probably looking at the options to recharge the batteries daily.

If you took the solar option you would need more than three 100W solar panels for that based on December sunlight figures. Cost about $3000 - $4000 just for solar panels.
An example of how to get figures for locations and time of year at this link. This is the first one I found using google so there may be better ones.
http://www.energymatters.com.au/index.php?main_page=performance&climate=536526513&town=Springfield&state=QLD&country=Australia&solarpanel=31
This indicates for Springfield near Brisbane you would get 31.8 ah per day from an 85 watt panel. Some simple maths indicates a 100W panel would give you about 37.4 ah per day. You may need 120 ah per day so one panel obviously isn't enough. Even three 100W panels is still a bit short.

I've also assumed perfect conditions for solar. No bad days or charging losses to give a worst case 12v fridge and best case solar scenario.

There are issues with generators in some locations (NP) so power becomes a bit of a costly issue.

If your fridge doesn't run 100% of the time and only runs say 25% of the time then one 100W solar panel may work.

I'd suggest doing some tests at home with the fridge to see how many ah it actually uses over a 24 hour period of typical use before spending big bucks on solar panels batteries etc. That way you will know roughly what your requirements really are and if you really want to explore those options. If you overestimate the efficiency of the fridge you will end up with flat batteries and warm perishables.
You may be better off saving the fridge for powered sites and where you can charge the batteries daily with a generator.

You may also find it a lot cheaper to buy a gas fridge than setting up for solar powered fridge.

I hope this hasn't made it more confusing :)
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Re: battery charging

Postby GypsyLady » Fri Sep 18, 2009 7:57 am

tezzaglen wrote:christie engineering make a petrol powered battery charger for around $990 it uses an alternator to charge the battery the same way your car does

regards

tezza



An alternator will not charge a DC battery to full capacity, so IMO not worth the money.
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Re: battery charging

Postby Smileandhug » Fri Sep 18, 2009 10:40 am

This may help you Dea.

For sustainable power, you need to use deep cycle batteries. Deep Cycle Batteries are very different from starting batteries. They have much thicker lead plates and are measured in Amphour capacity. Vehicle Starting batteries are measured and rated in cold cranking amps (CCA ).
The best battery type for off road travel is AGM (Absorbed Glass Matt) Deep Cycle batteries.
How long will the batteries last?
The manufacturer quotes a typical service life of 300-1200 cycles. It can be longer and it can be shorter depending on how well the batteries are looked after. The deeper the discharge of the batteries on each use the less the cycle life. However, 600 cycles is typical if 3-4 years use for most people, probably longer.
To charge ya batteries?
It is important to have 4 ways of charging when off road:

From the vehicle whilst driving
From a solar panel(s)
From a generator
From 240V at a powered site
How easy is it then to set up solar panels?

Solar panels are best set on their own simple stand pointing at 38 degrees upright in the direction of the sun. It is better to have 3 x 50W panels than one large 150W panel. This allows you to set the 3 smaller panels at angles to each other to get a more even power as the sun traverses the sky.
The other important factor for solar panels is to keep the back of them cool. So open panels with a simple folding leg is the simplest and the best.

Do you install the solar panels on the roof?
I installed my solar panels on the roof of the cage I mount to the top of the ladder racks on my ute when i go camping.These are angled on either side so they are not in the same orientation. However, as ya no if ya park in the shade the capacity limited. But the advantage is that they are constantly charging.

What is involved with a generator?A Generator is easy to setup and run. The disadvantages are the noise, carrying fuel and topping the fuel up. If the generator runs out of fuel, there will be a large power spike which can "blow" electronics if there isnt a surge protector.

What type of battery charger is installed?

The best type of charger is the intelligent Multi-stage chargers. The capacity depends on the model purchased but is typically 10A to 40A. The higher Amp rating reduces the time to charge on 240V. Multi stage chargers are all true “connect and forget” chargers. Once the charger has completed its charging cycle, it drops to a safe “Float” voltage to maintain the batteries charge. It monitors charging voltage, current and time to make a truly smart decision about when to stop charging. The output of the charger is also perfect for all sensitive DC applications like computers and mobile phone chargers.

Can you use an Inverter? How does the Inverter Work?

There are 2 types of Inverters. An inverter converts 12V power from the battery into 240V AC power. The highest quality type is a high power (1500 to 1800W) pure sine wave unit. As a guide, this is nearly the AC power from a Honda EU20i generator. At high loads, an inverter will drain the batteries quickly. However, they are perfect for running certain devices in the bush. For example, the Panasonic SD251 Breadmaker will use only 53Ah and take less then 2 hours to make a 1 kg loaf of bread. The microwave can be used to reheat those stews and other tasty leftovers very easily.

The second type of inverter is a Modified Square Wave 500W unit. It will run the laptop computer, phone charger etc. All these devices convert the power back to DC again (though generally not 12V DC) It won’t run devices that use an AC motor directly or use an AC “clock”.
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Re: battery charging

Postby GypsyLady » Fri Sep 18, 2009 11:14 am

Some really good info there JG, thanks.
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Re: battery charging

Postby itchyvet » Wed Oct 28, 2009 7:24 pm

Whilst the question was about recharging batteries, no suggestions were made regarding USEAGE of fridges and specifying between the different types of fridges available on the market today.
I notice the poster did not advise what type of fridge was being refered to, we all assumed it was a 12 volt compressor fridge.
So let's clear the air somewhat.
:+
There are mainly TWO types of fridges available for our useage today.
The first is the THREE WAY FRIDGE, which utilises chlorine gas under pressure. The gas is super pressurised by heat, this heat is generated by either a gas flame, a heating coil of resistance wire powered by 12 volt, or another such wire powered by 240 volt.
As the 12 volt operation relies upon a resistance wire, these fridges have a tendency to be POWER HUNGRY when operated on 12 volt, therefore NOT recommended for such operation.
Alternatively, when operated on LPG these fridges are silent and can run for two weeks at a time on a 4.5 kilo bottle of gas pending on your temperature setting.
Down side of gas operation, is loss of efficiency in tropical areas. However, for the home handy man/woman, this can be dealt with by affixing Computer fans to the rear coils with a speed control thus allowing faster air transfer over the coil thereby negating the effects of tropical climes.

The 12 volt compressor fridges operate differently. They are fitted with a 12 volt compressor which runs from a 12 volt supply, being from car, deep cycle battery or power supply from 240 volt mains.

The trick with either of these fridges is to fully stock them 24 hrs before you depart, allowing the internal temperatures to come down to set levels thereby reducing the load on the compressor and the demand made on the power supply once you get under way. Keep them in a cool place and ensure there is sufficient air flow around them when transporting in your vehicle, air flow is very important, as it transfers the heat away from your foodstuffs. Reduce the airflow and your fridge becomes less efficient.

If you've chosen a threeway fridge, it's really no big deal to operate successfully. Stock it as above and plug it into 240 volt 24 hrs before departure, believe me, it will cool things down pretty efficiently in that time. Place fridge in car ensuring adequate airflow and plug in 12 volt source.
IMPORTANT, many cars today, DO NOT HAVE ADEQUATE wiring to cater for the loads such fridges may require from time to time, therefore ensure from your friendly auto electrician, yours IS adequate.
In our case, I've had a relay installed, so as long as the engine is running, so is the fridge, turn engine off, and fridge is off too. This is to ensure the fridge doesn't flatten your battery.
I've found that three way frdiges running on 12 volts work perfectly fine in this manner.
Arriving at campsite, fridge is removed from vehicle and connected to LPG and remains connected for entire camp operating faultlessly and silently.

Compressor fridges require 24 hour cool down same as 3 way's do, then place in car and connect to 12 volts, requirements for air flow and electricity supply, are same for these fridges as for 3 way wiring.
Once you arrive at camp site, remove fridge from car and connect to your CHOICE of 12 volt power.
As many posts here have already demonstrated, there is an abundant choice of what that could be, however which ever choice you choose, ONE of them most certainly will be a battery.
I would advise such a battery be of the largest capacity you can afford in AMP HOURS, said battery MUST be FULLY charged before leaving home and of course your fridge temp is also at it's required setting.
Provided this is the case, and battery capacity is of robust standard, with reasonable useage, I'd expect the battery to last for at least 36 hours, provided no new warm foodstuffs find their way into fridge.
Now, if you've connected a solar panel to such a set up from the moment you've placed it from the vehicle on the ground, and the capacity of panel is at least 80 watts, I see no reason for it not being able to keep the battery capacity at acceptable levels for the time you are at that camp.

WORD OF WARNING HERE;
Fridge sellers do not warn purchasers of the risk of FIRE, from overheated wiring, especially if fridge leads are allowed to double up on themsleves in vehicles and have objects placed upon them.
NEVER allow them to tangle or double up on themselves, and never place objects particularly flammable objects on top of them as they get hot, and there are cases on record, where vehicles have been lost as a direct result from such fires.

For my money, and simplicity's sake, I recokon the three way lpg fridges are tops. All you need is a lpg bottle and your away.
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Re: battery charging

Postby Derek Bullock » Wed Oct 28, 2009 7:32 pm

itchyvet wrote:Whilst the question was about recharging batteries, no suggestions were made regarding USEAGE of fridges and specifying between the different types of fridges available on the market today.
I notice the poster did not advise what type of fridge was being refered to, we all assumed it was a 12 volt compressor fridge.
So let's clear the air somewhat.


It is a compressor Fridge. See this post - viewtopic.php?t=4255

Good post all the same.
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Re: battery charging

Postby oldtrack123 » Wed Oct 28, 2009 9:45 pm

Hi itchyvet
Congrats, An excellant post with the sort of detail, that gives someconfidence in your info.
BUT, one small correction, Not chlorine gas. It's charged with ammonia & water
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Re: battery charging

Postby itchyvet » Thu Oct 29, 2009 12:52 am

oldtrack123 wrote:Hi itchyvet
Congrats, An excellant post with the sort of detail, that gives someconfidence in your info.
BUT, one small correction, Not chlorine gas. It's charged with ammonia & water


I stand corrected. Knew I had it wrong, but for the life of me, couldn't remember exactly what the proper stuff was.
One thing for these boards, we can always expect someone to know the answer sooner or later, HEH !
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Re: battery charging

Postby oldtrack123 » Thu Oct 29, 2009 1:53 pm

itchyvet wrote:I stand corrected. Knew I had it wrong, but for the life of me, couldn't remember exactly what the proper stuff was


Hi
No problem, we all have our senior moments, getting more & more frequent in my case.
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