Loading and Inverter performance

[Ivan]

Certainly a flurry of useful comments and observations!

I agree with Antman's comments - these additions would make a very worthwhile improvement to the product, but not without cost. The solardin 120 is as I see it an almost perfectly designed product- it is designed with price in mind and although it gets hot in use, it was only ever designed to accept 120Wp panel input. The 'p' is quite important (peak watts) - at these lattitudes, 120W of panel is going to produce no more than 100W under most conditions - thus the unit is really designed for more like 100W input.

It does seem wasteful having to put 7w out of say 100W into the fans...but then again, if you compare it with spending the extra money on a higher powered grid-connect inverter, you have to consider the alternative use for your money, which would be to spend the cash on larger or more panels! It might be possible to modify something like an off the shelf variable speed CPU cooler or something along those lines to avoid wasting those watts unnecessarily in low solar conditions, but you have to consider the cost/hassle compared with spending the same amount of money on more panels!

With the fans running, the temperature is lower, therefore it allows the system to operate at higher output for longer. I suspect (although please make it clear that I am not advocating this, and accept no liability for any damage occuring as a result of trying this) that with the fans running, the unit is probably capable of handling rather more than the 120Wp rating - it would probably accept 150Wp or more.

Regarding the battery experiment, I tried this with my Soladin120, as I figured it could be a possible cheap method for grid-tieing a 24v wind turbine. What I discovered was the MPPT system is not really compatible with a fixed voltage battery input, and so it was very variable, sometimes it would feed high power, other times low power and sometimes it would feed nothing at all (which was a bit worrying at the time, as I thought I might have fried the poor thing!).

Ivan

[Bill H]

Good evening all.

Sounds like maybe a challenge from Ivan to you Mickey - another test with a single Soladin unit, two 110wp panels feeding, with cooling fans on - what can it handle !    No liabilities accepted of course.      (Word of possible comfort - my unit let me know, with no adverse effects, just flashing red LEDs, when it was uncomfortable, at least in the input voltage domain)

Maybe also there might be a way to easily attach a more heavy-duty heatsink to the device - an aluminium plate for example ? Or is that a naive comment ?      Incidentally - is there a difference in the Soladins ?  my 120/54 has cheap-looking plastic case.....

I'll re-run the battery test later - only ran it for a few minutes - and see if there is a temp pick-up over say an hour - I'll use a laser temperature probe thermometer and try to see if there are any obvious hot-spots.

All good fun - but seems like we need to be looking to rather more heavy-duty kit to make a serious impact on KWh delivered to grid ... S600 perhaps ?  Nominally around six times the power handling for four times the price, and apparently much more leeway in terms of the allowable inputs.    (or maybe we could simply lobby Ofgen to get towards Euro compliance on 230 VAC and bring the GF250 into play..... on the other hand....  maybe not !  )    Antman's comments are basically right on, IMHO !

best regards

Bill

[Mickey]

Hi Bill,

Yes, I did try running a single Soladin with qty 2 110w PV's and the max power seen was 93wp with the fans ON.  This compares with a recent result of 191wp with both Soladins connected with the fans OFF.      The ambient loft temp at that time was 24Deg C.

All this leaves me to believe that the fans make little difference when the loft ambient is below 30deg C.  However, with the cool fickle weather of late I can't continue my investigation at these higher ambient temps.

One thing is that in the mornings the fans are absorbing power unnecessarily and can be switched OFF but later in the day if the ambient climbs to 30deg C'ish  then the fans should be of benefit.      I'm thinking of using a cheapo room stat to control them.

Also a single fan may do the trick this would save power.

I look forward to your battery re-run experiment results?

Looking more closely at the Soladin's case and it is a hard plastic sprayed brown

Good luck  Mickey

[Ivan]

Loft temperature is likely to get very high on good solar day - above 40C is easily possible. Is it possible to site the soladins outside the loft space (ie in the house ) - this will certainly reduce their temperatures on hot days.

Ivan

[Mickey]

Hi All - I've been running my trial for a few weeks now and have taken on-board all the very useful comments & recommendations - thanks.    As I mentioned at the start  of this topic - doing an experiment, like this, with so many variables is nigh impossible to reach a firm conclusion.  However, for what it's worth the results are as follows:

Week 1  (No Fans)  = 4.86 kWh
Week 2  (Qty two Fans ON permanently) = 3.90 kWh
Week 3  (No  Fans) = 4.79 kWh
Week 4  ( Qty one Fan ON controlled by a thermostat set at 28 deg C loft ambient )  = 4.90 kWh

The weather has been mixed throughout with no really clear days but I'm going to leave the system ON as week 4 and check the results every Sunday morning.

One thing for sure is that my 30 tube thermal system is the best investment  by far.  With end of day temps (TSTU) of around 60degC. - every home should have one ( where practicable).  Power to the people!

Mickey