new here advice needed

[zulupaul]

hi im new on here ,living in spain off grid ,i have a 16 panel array with a tracker and my pv panels are p115wp 1000w/m2 ,which go through a stecca tarom 440 regulator ,i have 24 x 2 volt 420ah fiamm batteries and a xantrex invertor c70 i think ,big heavy thing ,with a pramac 10kw (8.5 kw actual) back up generator ,im tring to find which are the best settings for my whole system can anyone please help,thanks in advance paul

[Cariboocoot]

Welcome to the forum.

Let's see if I've got the specs right:

Sixteen 115 Watt panels = 1840 Watts total
Steca Tarom 440 - 40 Amp 48 Volt PWM controller
Twenty-four 2 Volt 420 Amp hour batteries configured for 48 Volts.
Xantrex inverter. Never heard of a 'C70' though.

You could probably expect the panels to produce 25 Amps maximum @ 57 Volts charging, slightly low for those batteries (they're no doubt "tall case" ones and would want 44 Amps of current). Could yield 5.6 kW hours per day, low compared to the battery potential. Probably see 3.6 kW hours AC potential per day.

That's just rough calculations based on "typical" factors; not a precise estimate by any means.

Not sure what information you're looking for (charge Voltages? Absorb time?) but the battery FAQ's are always a good place to start: http://www.windsun.com/Batteries/Battery_FAQ.htm

[zulupaul]

hi thank you so much for that it is all very helpfull and expanding my knowledge ,but what i need is what i should adjust the settings to on the stecca and the xantrex which ive found out is a sw4548e ,i think my current batteries are shot as they are not putting up any specific gravity even when soc shows up too 100% ,do you have any ideas i what i should replace them with as im spending or on fuel than im saving with the solar ,i was thinking like a 1000ah for longer supply and as we have good sun here ,and the exisiting are the tower sort yes,thanks in advance again ,it is all very helpfull,paul

[stephendv]

Bienvenido!

For those cells, I would set:
- Absorb voltage 2.4V
- Absorb time 3 hours
- EQ voltage 2.6V

These should be set both in the Xantrex and in the Steca.

If the SG isn't increasing then try an EQ charge as soon as possible. Keep EQ'ing and monitor the SG every hour. If SG stops rising after 2 hours, then stop the EQ charge. And check the electrolyte levels during the EQ.

For the SoC calculation of the Steca to work properly you either have to:
a) Connect the xantrex to the output of the Steca (which will limit the output of the xantrex to 2kW, so not the preferred option).

OR

b) install a shunt between the battery and the xantrex and connect it to the steca so that it can keep track of how much energy is leaving the battery via the Xantrex. Without this, the steca can't keep track of energy going out, only energy coming in though the solar panels.

You should base the battery bank size on your loads and number of days of autonomy. How much energy do you use daily? And do you use the system year round, or seasonally?

[zulupaul]

thanks again,but being a novice how do i actually do that please ,paul

[stephendv]

Steca has their manual available online which explains everything about how to install, program and operate it.

Xantrex was recently bought by schneider-electric, so you might have to do some digging before you find the SW manual.