Submitted: Tuesday, Feb 12, 2008 at 19:58
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I am new to solar camping technology and have inherited the following Solar Panel with the purchase of a second hand camper trailer (no documentation provided). I am wondering how powerful this would be - have just purchased a WAECO CF50 fridge and hoping to charge duel battery system. What the likely charge from this unit on a sunny day?
2.5 AMPS Peak Power current
16.8 Volt Peak Power Voltage
PVM 4500
TYPE 2 Module
Class A or B

Have also inherited a Solar Converter to 12V (GCR M, 2000, BP Solar) again no documentation.

Any hints on best way to run this system - if worthwhile at all?

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Reply By: Sand Man (SA) - Tuesday, Feb 12, 2008 at 20:35

Tuesday, Feb 12, 2008 at 20:35
With a 2.5 amp peak power output, my guess is a 40 watt panel.


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Reply By: Mainey (wa) - Tuesday, Feb 12, 2008 at 21:01

Tuesday, Feb 12, 2008 at 21:01
the Philips 2.5 Amp solar Panel would be too small to *fully maintain* the running of a Waeco CF50 fridge.
The Philips panel will require assistance from the vehicle engine to maintain battery performance.

A larger 80 watt (4.8 Amp) panel would be a better choice for longer stays.

It's definitely 'worthwhile' to you, to "learn" more about solar power.
Connect what you have up to a 'battery' and connect the fridge and let it run at home with the fridge 1/2 full of water bottles etc.

The type of battery is VITAL when you have a smaller sized solar panel to power it. If you don't have a battery now either make the decision to get a solar system or stay and play with your inherited toys.
If you want to spend some money then get an AGM Deep Cycle battery, because it WILL charge much faster than any other type of battery.

Mainey . . .
AnswerID: 287135

Reply By: Member - John and Val W (ACT) - Wednesday, Feb 13, 2008 at 08:10

Wednesday, Feb 13, 2008 at 08:10

As already said, your panel sounds like a 40W unit, and although it is some help, you will be relying on good storage and charging from the vehicle. My rig consumes about 35 amphours per day and I use two panels, 60 and 85W, which is more than enough unless we get extended overcast weather.

Suggest work out your daily requirement - the fridge is the main consumer. If you can decide the ratio of on to off time of your fridge and it's current consumption that will probably account for at least 80% of your daily usage. eg If the fridge draws say 5 mps and it's compressor runs for 1/3 of the time, that's 8 hours at 5 amps = 40 Amphours per day. Add 20% for lights, charging batteries in camera, laptop, torches, running the radio, etc .... and your daily consumption is about 50 Ah.

Assuming say 6 hours good sunshine per day you'll need at least 50/6 =about 8.5 amps to fully cover your daily needs. In practice, you'll probably be charging also from the vehicle while the engine is running, and your daily demand probably isn't as high as I've suggested. Adding a 60W or 80W panel to the present one, and a 100 Ah battery for storage should give you a good reliable setup.

There are a few traps with this gear, so a couple of further comments -

1) For this type of application you need a deep cycle battery, rather than the type used for starting the engine. Typically you'll use a 100 Ah size, though smaller and larger are available. Any battery will die prematurely if you repeatedly draw more than about 2/3 of it's capacity, so best not to assume you have access to the full capacity.
2) Although solar panels are rated in watts, where watts = volts x amps, their peak power occurs at around 16-20 volts. We can't use more than about 14.5 volts for charging batteries, so although the peak current is still (largely) available, the full wattage is not.
3) With any panel larger than your present one you will need a controller to ensure that when the battery is fully charged and draws less current from the solar panel, the charging voltage doesn't rise excessively and damage the battery.


J and V
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