Solar setup on camper

just an aside...

What amperage is the regulator (ie 10A, 20A etc)

A 64W panel will only send u between 5 and 6Amps (max) throught the regulator.

however, if your 80Ah battery is down, and you connect it to ur auxillary and its still running through the regulator it has the potential to draw far more amps than the regulator is designed for.

As just like when jump starting, the run down battery will try and draw whatever amps it needs to replenish itself.

Rev

Gday Stu

Your best bet would be to ask the people you intend to purchase the equipment off as to the consequences, as they should have a better understanding of it.

Cheers

Rev

went through all this solar panel thing last year. from research found out unisolar was problem with size compared to crystalline and price per watt
size of panels
u64w 1367mm x 742mm
110w crystalline 1315mm x 661mm
80w crystalline 1195mm x 541mm
55w crystalline 996mm x 446mm
that makes the u64w a whopping 15.8 sq cm per watt against 8 sq cm per for crystalline. this is double the size and a problem for carrying and wind

also found out 64w was not sufficient solar for more than 3 months over summer to run 40l fridge and fluoro at night full time. that did not suit at all as wanted sufficient solar capacity to power fridge all year. the more researched solar and spoke to people with solar found those with not enough solar power had to make up some other way for not having enough solar capacity and they were not happy campers the store they bought the solar from had lied. 2 families spoke to with solar had sold the u64w and bought bigger crystalline panels and were happy campers now with the solar setup
from u64w you will get 3.6 amp and using 40l fridge in summer approx 30 amps per day and 6 to 7 hr of sun mid summer to charge battery leaves you short of power and flat battery

price for u64w $640 = $10 per watt
price for 80w crystalline $595 = $7.44 per watt
due to mounting and so could take off camper and park in shade and have panels in sun bought 2 x 55w crystalline for $410 each = $7.45 per watt
the 2 x 55w = 110w are the same area as u64w
difference in price from u64w to 110w = $180 so nearly 2x power for little more money
moral of the story is u64w is poor value for money and problem with size if you need to buy more solar capacity as u64w is not enough solar to do job properly to power 40 l fridge

purchased a 20 amp digital regulator Powertech for $139 incl postage
this reg in the history shows 40l fridge uses 25 to 35 amps a day in summer and 16 to 25 in winter
2 x 55w gives 6.4 amp and is good to power fridge and fluoro light

overall happy camper and glad I did my solar homework well
those stores that tell you u64w or other small panel will run fridge full time and light up your camp are wrong

Stu, do you mind if I ask ballpark cost....?

Hi Stu A,

If you go to the Directory on this site & look up Caravan & Motorhome Books you will find a good article by Collyn Rivers. Also look at the books he has written & I'm sure you will find a title that will suit you. For a novice it is a good place to start & get some info & he provides a wealth of info on a range of sets ups for Campers etc.

John

If you are planning on staying 'put' in one spot for a week with a 64w unisolar and the setup you describe you are really kidding yourself...think about maximum 2 days...as for all the other ideas ..well really just get more capacity batteries (like about 400ah setup ) and about triple your panels and then you will have a chance...or instead a small genny and run it every day and bleep the other campers off no end!! It all depends on so much to be factored that trying to 'guestimate' the cheapest solution is an infantile waste of time...SOLAR IS NOT CHEAP OR EFFICIENT !!!!! (IMHO) !!! and I have it !!

Stu

Few brief answers.

1. Single Unisolar is not adequate for the load. Suggest minimum of single 120-watt - but always spend most on module/s not battery capacity because if you cannot generate it you cannot store it.

2. Shadow tolerance. Uni-Solar is way ahead re this. But shadow tolerance does not mean 'shade' tolerance, rather than if a Uni-Solar module is partially shadowed by say a small tree branch - the loss is roughly proportionate to that area shadowed. With other modules you more or less lose the lot!.

3. Essential to use adequate size cabling.

In one of my books I relate fixing a solar set up - where the owner had about 60 metres of twin flex connecting a bank of eight 64-watt modules to his Engel fridge (that barely worked at all). The voltage loss was over 2.0 volts. Replacing that cable by a single heavier one three metres long enabled that fridge to run on one just one module!
Collyn Rivers

Here are some quotes from the Steca Manual -

"Never connect another charging source to the charge regulator. This can destroy
the regulator and/or source."

"Observe that there is no common connection, e.g. across a ground connection, the minus module connections, battery minus and load minus. Non-observance can
damage the regulator!"
- if you connect the car 12 volts to the Reg input and the CT battery to the Reg Output, you will short-circuit the currnet sensor through the Towball.

Other Regulators may work differently.

Mike

"2x fluro lights (1ah each for 3hrs per night), water pump (7ah 10mins per day) and shower pump (2ah estimated, 15mins per day). My 100 series has a dual battery setup and the 2nd batt is a 55ah deep cycle"
- The current that a device draws is measured Amps (A), NOT AmpHours (AHr).

If you want to work out how much of the batteries capacity your appliances are using, you need to calculate Amphours -

2x fluro lights (1amp each for 3hrs per night),
= 2 x 1 x 3 = 6 amphours per day

water pump (7amp 10mins per day)
= 7 x 1/6 = 1.2 amphours per day

shower pump (2amp estimated, 15mins per day).
= 2 x 1/4 = 0.5 amphours per day

So the total capacity used per day by these three appliances is per day is -
6 + 1.2 + 0.5 = 7.7 amphours.

The capacity used by the fridge depends very much on ambient temperature and usage pattern.

Mike

Stu

Firstly I agree with Diligaf re the regulator: either his suggestion - or my usual preference of Plasmatronic (that preference being mostly because I am far more familiar with the latter and what one can do with it). Both are excellent choices.

Re confusing measurements. There will be a problem if a second battery is connected to the system as the charge history of that battery is not known, or knowable to the regulator at the time of connection. If the two batteries were paralleled then the regulator would read the ingoing charge to both, and the current draw from both. The Ah in/out data would thus be correct.

But, as the previous history of the second battery is unknown to the monitoring system, the 'percentage remaining charge' would become meaningless.

It would all work itself out over a few weeks as the sytems automatically recalibrate now and again - but there's no way you can get an instant readout.

I'd be inclined to accept that the above will happen - and simply ignore the % charge indication completely: in any case it's quite rough and the Ah in/out is quite and a lot more accurate. As long as 10-12% more comes in that goes out (on average) - and the max voltage exceeds about 14.5 on most days all's well.

You could do what you wish by using individual current shunts on each battery - and separate metering - but it's all gets to complex to be worthwhile.
Trust this helps
Collyn Rivers

All this complication and expense: why not simply stay with (or upgrade) the gas fridge? You're AGM battery will then handle the remaining load for ages.

Mike Harding