Land mark day today

[Justme]

I would try to ditch the two 175w panels & get more 165w ones. You can mix panels but really need the strings to match (not watts but the other specs) as close as poss.

Why not go to 3 panels in a string @ 132v? As long as the temp adjusted V is still under 145v.
Hum yeh bit close for comfort. So perhaps 2 is better.

Mine is in 3 strings of 5. The newer 5 are slightly dif in spec to the older 10 & are mounted at a steeper angle so give diff performance (but then so do the other two strings as they catch the sun differently). If I trip two strings out & read the stats & then rotate to the other two in turn the combined stats are the same as I am seeing in total on the meter. So I guess that tells me that each string is working on its own even though they are going into the controller down one wire after the breakers.

So ditch my other comments & use them in 7 strings of two.

Justme

[billi]

cant dump the  175 ones cause part of the deal  , sure i thought of 3 in series and three of the 175 watt ones but that then brings me to  then over the 2500 watt mark , but like found out perhaps ok if volts are fine ( i reckon they are )

I did rewire my existing  panel/setup , because found a bad connection ( cooking hot )  and have to rewire the whole lot to achieve a better performance later  (finally got  real PV cable 100 meter 6 mm2    looks too big  to me , but  two beer are better than none )  my last used cable cannot cope with UV and coast condition

its now only about 33 volt (connected)  for my 24 volt battery  and volts are getting down to 29 V when warm , but still  the chargecontroller when starting to absorb lifts up the volts its self to over 33 V  Very happy with it

Tells me again Buy Less But Good

Billi

[Mike McMillan]

I have 8 x 180 watt 24v PV panels feeding into 2 banks of 100 amp batteries. I haven't had to run the generator since March. We average about 1 KW of use a day, including tele, lap top, fridge, washing machine, solar collector pump and hoover. The fridge is outside as doesn't use much power. Hoovering and washing machine are managed according to conditions. The batteries are usually fully charged within four hours of sun shine at this time of year.

Mike McMillan

Very dry Isle of Wight

[billi]

well done Mike  ,

 but what are 2 banks of 100 amps batteries ? And if you have 200 AH at 24 volt , are you  not scared to run a washing machine from them ?

Billi

[Justme]

Wow 1kwh is seriously low.

I thought I was doing well to hit 1.9kwh.

You must be getting 5-7kwh per day from the solar at the min.

What are you doing with it all?

Billi

I would worry about going to 3 x 44v = 132v unless thats the highest they can be in the coldest conditions that you have.
The cold can add on quite a lot of volts.

Have you played with the string tool on outback forum?

http://66.34.95.46/applet/index.html

Mine have a spec of

Open Circuit Voltage (V): 21.88 + 2 (so max 23.88)

I have seen v of 116v in May (I dint start keeping v until may) so thats 23.2v per panel. I expect it to go higher in winter.

Between plus 30 deg c & -10 deg c you can add more than 15v on my sytem.

Justme

[Mike McMillan]

Sorry, typo, it should be 2 banks of 200 ah ( 2 x 200 varta lead acid). I have both banks in Parallel, but they are switchable . They are 4 years old and still performing as well as the first day. I do regularly give them an equalisation boost. Being off grid, the excess power just gets dissipated by my controller. Sad really, I have only recently (march) upgraded from 4 to 8 panels, which means that I can usually get a full charge even on cloudy days. I monitor daily consumption on the efergy meter, which gives me the a.c consumption, but the dc is only a couple of lights. I also tripled my solar collector area from 2 x 15 x 58 to 6. Two panels would comfortably heat 250 liters of water from 25 degrees to 60 on a sunny day. I was expecting enough excess with 6 panels to seriously heat my 300 gallons of water in my radiator system. Surprisingly, most of the extra heat just tops the tank up to 80. It does a few pumps through the heat dump to take it down to 70. The big advantage is that I still get hot water on cloudy days and the tank is up to 60 by 10 A.M. I have to light the oil fire if I want hot water in the summer, so again, the extra capacity has meant no fires since March!

Mike McMillan

sunny and hot Isle of Wight

[billi]

Good stuff Mike

Justme i know its close , but we have no frost = never below 0  during the day ( well we never know what the climate will be exactly ), good tool that is

but have not decided yet ....  and preferable  id stay with two panels in series , but would mean i have one left over  that i can use for something else

billi

[Bill H]

but would mean i have one left over  that i can use for something else

billi

I have an 85 watt panel bought from one of the novelty rip-off suppliers before I went heavier duty.    Specs don't fit my other Navitron PV kit, so I use it to charge a couple of 110 amp hour bats, which then charge my electric bike for riding to work outside the dark months.  Works great - ten miles to/from work, only needs 200wh to do the trip (plus a limited amount of muscle power !)   Of course, the charging/Inverter/charging losses are ridiculous, but with energy to spare, who cares !

Good work Mike !

regards

Bill