What sort of wattage should I go for? We use the Propex, devices and charging of devices. And the absobsion fridge but the latter is not really a realistic use of a solar panel I think. Sent from my SM-G780G using Tapatalk
100w does it for me , probably not enough for most but I'm realistic and don't expect too much . I'm not one for orientating the van for optimum sunlight so could try harder but seems to cope running the usual Dometic crx50 even on overcast days although never used as a freezer and unless it's scorchio switched off at night . Interestingly before I fitted the panel I could easily get a weekend away from an 95ah leisure battery and split charger prior to fitting the propex... Devices - negligible , 1 x phone . Propex use is a couple of hours before bed and an hour or two on a morning but only if necessary . I never sleep with the heater on ! Like I say , sensible with it Sent from my SM-G960F using Tapatalk
With all these things the only way is to do a spreadsheet of amps drawn times hours run, add up the total and then do the same for the solar panels guestimated amps times hours. If the sum of loads is less than the sum of solar energy input you are winning.. until it rains or is cloudy for a few days and then you are just running on stored energy from the battery.
I don't have spreadsheets , just a little smiley face that tells me all's well ... Sent from my SM-G960F using Tapatalk
What I meant was you use the spreadsheet for sizing the various parts of the system before building it or choosing solar panels and charger system and battery type and capacity. Work out expected usage, estimate expected input , then discover you need a massive battery that will never get charged because you went camping off grid for a cloudy week. What your smiley face is saying is all is good with your installation on a moderately sunny day with a not totally charged battery.
I know what you meant Mike but I prefer the simple (smiley face) approach.. I rarely stay in the same place for more than a couple of nights and if the smiley face decided to follow the weather and take a miserable approach to the day I'll just head for a campsite with electric and top the battery up . Never had to though ... Sent from my SM-G960F using Tapatalk
An absorbtion fridge will need probably 300-400 watts of solar panel and very big batteries.. to accomodate being able to charge the battery while still delivering a steady 7 amps 24/7. Overall cheaper to get a compressor fridge.. A Propex draws just under 2 amps but realistically it can be used to take the edge off the chill for about 10 mins. The compressor fridge uses 4 amps when cooling , (and 0.05A if its got Bluetooth when its not) at night , if you let the temperature in the bus drop by not using the Propex, the drain of the fridge drops too.. So over a day, the fridge draws average about 1.5A or 36AH. The Propex a lot less . 100w solar panel working flat out for 8 hours is about 60AH.. so ideally need 200W with a compressor fridge even. If you run the Propex for say 5 hours a day, and 20 on standby thats 10AH.. and 0.85kg of stupid expensive Camping Gaz or about £20-£30 if it comes in a 904 cylinder. Its why I am now trying to work out where I can fit a gas locker with a decent height for bigger cylinders..
I used first decide about my requirements (e.g. 2-3 days in sunny areas without 230 V shore power and without driving and use of generator power), update my old electric parts (e.g. a modern compressor refrigerator is more economical and colder than old absorption refrigerators), I estimated my consumption by Watt or Ampere data / measurements for day and night (at night no solar power, possible less consumption by switching off things), I calculate/estimate the consumption and the solar power (but not too optimistically), buy parts, do some tests before the laborious installation, after installation make a test drive weekend... and hope that it works in real live otherwise it need to be improved... I wish you success... regards
I'm always impressed by your set up @Lasty! I'm sure mine never produces that many amps... so my question is (and may be investigated at techenders) - to produce a smily face and numbers like that, was your leisure battery particularly flat and needed a decent solar boost on a sunny day yesterday to fill it up? Did you have the fridge on? Or is that just what it does? I need to experiment with mine now that I have a 12v fridge I can actually use off the leisure battery (no more absorption, hello compressor) and see what the solar is actually doing!
As I understand it, if you can keep the panel tilted and facing the sun as much as possible the efficiency of the panel can rise by over 30%. Edit....and clean, which I often forget
I just went overkill 300W That way I don't have to worry what way I'm facing my batteries are usually full by 10am Panels are Renogy 100w Sent from my SM-G981B using Tapatalk
Excellent , so pleased it's not only me who just parks up not caring where the sun is . To be honest I get a few amps even on overcast days so I'm happy with that - enough to keep the beer cold , lights on and smiley face smiling.... Sent from my SM-G960F using Tapatalk
