kevtherev wrote:centro wrote:
So with the van being de rusted and naked inside, the old leisure is gone and the cabling and wiring is being renewed ready to fit The Trojans.
and this illustrates another important consideraton, somebody looking at a blank canvas is going to have very different ideas about ideal than somebody who already has a system which works for them...
i mean in my case everything comes back to the fridge...
Now remember that
1 - i'll rarely be near a hookup.
2 - That i want to avoid the hassle of charging from the home supply as much as possible.
3 - I like the idea of a van that takes care of itself
three way absorbtion fridge will be circa £250 - not exactly much choice style wise
4.5kg of gas is what, £16, and the consumption of an absorbtion fridge is 12g gas per hour ( the dometic rge2000 is 24 g per hour) so 1kg of gas lasts 83 hours & the bottle will do 15 days... making the ballpark running cost of the fridge £1 per day
an "A" efficiency rated 240v compressor beer/minibar fridge - loads of choice in the £50-150 price range - consumes 16w (LEC r5009 - £104))
add £50 for a decent inverter and allow 5w for its resting consumption AND add 10% for efficiency loss, and the fridge/inverter combo costs 23w per hour. or 1.91 Ah or 46Ah per day
gs55 thin film 55w solar panels are £55 ea - allow -10% (seconds) and the pairs 100w array should produce 6-700 watt hours, or 54Ah per day in summer - but only 6.7 Ah per day in winter.
£65 gets me a EPIPDB-COM 10A dual battery solar charge controller with remote display (to monitor condition of each battery & allow setting and changing of charge priority)
the capacity of the leisure batteries is a seperate consideration for now, i'll return to that in a bit
now we have defined the variables lets do the sums
gas fridge
£250 + £1 per day
solar fridge
£104 + £50 + £110 + £65 = £329 + 0 per day
so just looking at the fridge the payback period is about 80 days use... not bad on its own.
now lets look at the credit/deficit for this setup across the seasons
summer use
Fridge consumes 20% more than average so 55 Ah
panel produces - 54Ah, allow a bit for lighting and waterpump, with a tiny bit of input from the alternator and the bus can go all summer in "tickover mode" without needing any significant input
autumn use
fridge consumes 44 Ah
panel produces 35Ah - system runs at approx 12 Ah deficit - so can stand for about a week, 2 at a push before wanting power input (assuming 200 Ah of leisure battery) - will recharge itself in about 2 or 3 days (unused with electrics off & allowing a small contribution form the alternator
Winter use
fridge turned off
panel produces 6.7 Ah - enough for lights, pump and a phone charger (indefinate survival mode)
in winter weekender mode my 100 Ah usable battery capacity should let me run the fridge and a diesel heater for a couple of nights
luxury capacity
if i have 200 Ah of leisure battery lets say i have 100 Ah of usable energy - in Winter i can forget about using this for anything except essentials & maybe a couple of charges to the laptop
In summer it would buy me about 25 hours of laptop charging, or about 6 hours of a playstation3 & TV scenario.
in Autumn I could knock those times back by a third/half
so as a simple camper the above system looks like it does the job pretty well.
It should be capable of recharging itself fully between frequent summer use and weekend Autum use.
it will probably take 2 weeks to recover fully from a weekend in winter unless driven a bit or plugged in.
If I want a "luxury" camper capable of more high enery use especially in winter then I need to add an extra panel, another battery and a Stirling charger. Which would substantially increase the cost. This is the decision that I am wrestling with at the moment. What is the Diesel consumption Per hour for a van idling with a 50 amp load on the alternator? - need this to work out solar payback time against this power source.
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