Folding Solar Panels

Here's a question for the experts on this stuff.
I don't want to carry rigid panels with me or even mount them on the vehicle so I'm looking at the folding blanket type.
I'll be using 2 x 100ah AGM batteries to run a fridge, not at the same time naturally. so when one of the batteries needs to be recharged, which one of these would ya's recommend.
Probably also thinking of a genie as a backup just in case we don't get any sunlight here in the West.

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Cliff,

Go for at least the monocrystal 120W panel (that comes with 6A regulator) that you can fold away flat.
Run both batteries connected together in parallel for more capacity and less load shock, when your fridge goes down to temp the batteries will trickle recharge together and not lose voltage as quick some fridges will quit <11.0Vdc.
Don't forget idling the car (30A quick charge) for 15min by jumper lead can make up for cloudy days and having warm beer in the morning.

Otherwise 2 x 300W NEC Panels on your camper roof.  ND

thanks for the info Deet.
I've got a couple of these battery boxes with the 100ah batteries so I don't think I'll be hooking them up together.
Projecta reckons the 80W setup would do but I'm thinking for the extra $100 the 120W panels will be the better option.

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Forgot to ask, is this what you mean by regulator ?
" in-built 8.5 Amp solar controller"

Yep Cliff, 8.5A solar controller is laymans terms for peak panel output, but there are differences in them, they may not like extended charge periods or may go faulty if the output is shorted. The ones you get with panels are generally not quite as good as aftermarket units that can maximize the output from panels to the battery connected to it even in bad light (by keeping charge voltage constant, have bigger heat sinks on their regulators for extended duty and usually have good short circuit protection built into their design).

The ones with a panel however, should still shut off charge to batteries once charged up so they don't boil dry, something you need to read up on.

so can u replace the regulator already on the panel--reason being I think I have 2 faulty units 80w ---they r playing up--sometimes they charge sometimes they don't.

regards
oneday

Yep you got it Ray.
Disconnect the old Regulator on each panel to test.
Measure the raw voltage coming from the panel. If the output increases on voltmeter (or connected to a single headlight (low beam) increases in output with sunlight intensity nothing wrong with panel... (it may just be down on volts a bit if it's really old and lost a cell or two).
Just hook up a new 12V / 5A Regulator to each panel or hook up both Panels in parallel 12V to a 12V / 10A or in series to a 24V/5A Regulator for your 24V battery arrangement.

I have replaced my regulators which came with the panels .I was told to put them as close to the battery as possible to be the most efficient.Depending on the distance from panel to battery you may have to go larger cable.

Cheers

Phil

True Phil,
DC has voltage drop issues. so the regulator needs to sample the voltage at the battery and not the (battery + the voltage drop across the resistance of the cable to the regulator) a volt or so can be the difference between the regulator shutting off the battery charger supply early and say instead for charging up to 13.0V it only gets to 12.25V.
By increasing cable gauge or reducing the cable length your reducing the volt drop in a connected circuit (ohms law) Voltage Drop of the Cable and across connections in Volts = Cabling cct Resistance in Ohms / Current in Amps from regulator)
Power is lost as heat in the resistance in the charge circuit in porportion to the internal resistance of the battery on charge.
Power Lost (Heat) = Current in Amps Squared x Charge Circuit Resistance Ohms
if have a charge circuit with a lower resistance (shorter or bigger guaged cable used) the higher the voltage at the battery terminals and reduced error at the regulator switch sensing bias.

don't u luv it when these blokes talk dirty

regards
oneday

Bought one similar to this one last year, the regulator failed but they refunded me enough to buy another one. After that worked fine. Even after accidently driving off with Anderson plug still connected to ute. The panel cart wheeled a few time before the plug pulled out. Refitted one wire that had pulled out and she was a goer again.

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oneday wrote:don't u luv it when these blokes talk dirty

regards
oneday

Don't worry Ray, I don't wear an electricians coat all the time, as other already know, I out grew it courtesy of my addiction to pizza and cold beer and not doing enough digging for nuggets.

Here's a bit on solar controllers from the experts;

I just wish I could understand the foreign language      
I'll get the 120W panels, discharge the battery and see how it goes.

Bignuggs wrote:I just wish I could understand the foreign language      
I'll get the 120W panels, discharge the battery and see how it goes.  

Just don't discharge battery more than 65-70% of it's charge, other wise it may damage them.

(info below from the net)

Not all 200W panels are created equal, some are not
suitable for battery charging purposes.

Open circuit voltage should be 18-22V minimum.
FAQ:

Question: What can I run using this panel?

Under optimum conditions this panel will produce up to 10-11A of electrical current. This is at a cell temperature of 25°C, measured with a thermocouple from the back of the panel.  It's possible to generate more than 12 amps if at 0°Celsius, i.e. in snow and bright sunlight.

If orientated facing true north on a 25° angle, the panel will receive a yearly average of 4 hours of usable sunlight each day (2 hours in winter, 6 in summer. This is based on Melbourne, Victoria.)

So, 11A of current for 4 hours (4 x 11) is 44Ah at 12 volts. This panel will produce 44Ah of power, on average, each day.

Question: So what does that mean!?

If you have an appliance, such as DC fridge, you need to find out how many amps it draws and determine how long it will run for. For example, a 12 volt 50 litre Waeco fridge and 12 volt 30 litre Engel fridge will draw an average of 1A at 12V each (or 0.5A at 24V); most users will run this 24 hours a day. So, 1A x 24 hours = 24Ah. This means that you need a panel that produces at least 24Ah a day in order to replace all of the power used by the fridge.

Q: What size battery do I need?

A battery is a storage vessel, there needs to be enough room in the battery to store energy produced by the panel.

Q: So I need a 44AH, 12V battery, right?

Wrong! Deep cycle batteries should not be discharged any more than 30% (i.e. 70% full). Discharging a battery by 80-100% will break the battery, that is shorten its life expectancy very dramatically.  This means if one wants to store 44Ah of usable power, one needs a 146Ah, 12V battery (calculation: 44 / 0.3). More to follow. Rod.

As a rough rule of thumb we suggest a 100ah battery for a 40 litre fridge and a 200W panel. So an 80l fridge would need a 200ah battery and 400 Watts of panels. We allow a bit extra as you will probably have LED lighting and a mobile phone charger etc.

Make sure you match the voltage of the panel, battery, regulator and appliance! You must use a 24V panel with a 24V battery, or a 12V panel with a 12V battery. A 12/24V regulator will work on both systems, but the nominal voltage of the panel and the battery must match!!! (eg 12v or 24v or 48v).

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As Ray has been telling everyone (the dobber) I've been running my 45L fridge in the lounge room. It saves walking to the kitchen    as yes my gut is getting bigger     I'm getting lazy.
The thing I like about the arkpak battery box, when the battery hits about 10.5V, an alarm goes off and it has an automatic power shut off.
Now what 10.5V equates to amphours, I have no idea, so it's the reason I'll be using 2 x 100ah batteries.
I have been running the fridge on 1 battery for at least a full week at a time and it has never got anywhere near 10.5V. but like I said, it's in the lounge.
I've just ordered the 120W Projecta solar panels, hooked up the fridge to the battery again and I'll let it go until it hits the 10.5 mark.
The 8amp 240V charger I use gets the battery back to 100% in a day so I will have to see how the solar panel handles it as they reckon you can connect the panels direct to a battery without using the 240V charger.
It'll be interesting to see what happens.
Coz if I'm stuck out in the scrub without cold beer, all hell will break loose  

Cheers Woooooo Hooooooo

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G`Day Cliff.All you need is a cask of red in your survival kit if the fridge fails and bobs your uncle.
Cheers

Phil

I don't have an Uncle Bob but the cask of red is a good idea

I'm heading for a problem I think. I've been running the fridge from the battery for a while now.
The read out says it's still got 11.6V but the battery is down to 31% charge, or so the readout says.
I'm not sure it will ever get to the 10.5V auto cutoff without dropping the battery down to nothing.
Might give it another 24 hrs or do ya's think that is unwise.

WHY DO U WANT TO STUFF UP A COMPLETELY GOOD BATTERY--wait till u get your solar panels or simply put the charger on it to give it a ressurection. If its a deep cycle battery u will end up stuffing it completely.--god help us..

i think u need to go back to work....

regards
oneday

if it stuffs the battery, I'll buy another one.
you keep saying I'm a millionaire, dunno why

Yeah,I think I would be pumping some charge into the battery.They dont like to go below 70% and like Ray says,will bugger the battery.

Cheers

Phil

I've taken it off the battery just to be safe.
I have had it down to less than 50% before but this time the charge was low. it was actually 38%, I read it wrong, but the voltage was ok.
I couldn't see it gettin anywhere near the 10.5V without draining the battery or maybe the readout was not correct. so I got onto ArkPak and we'll see what they have to say.
It don't matter, now I'll wait until the solar panels arrive and see how long it takes to charge the battery.

The Projecta 120W folding blanket type panels finally got a work out at the muster but I didn't really need to use them.  I hooked them up to the battery that was running the fridge for a few hours, they did the job of putting a charge into a battery but a bit of wind and it blows them off the piddly little stands so I just had them laying flat on the ground.
The fridge ran nearly all week on just one of the 100ah batteries and never really reached the charge stage.  
But I'm now thinking of getting a set of panels like nuggiedreamer had and keeping the others as a back up.
Anyone used the Waeco 120W panels

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