3000w install in Australia

[dRdoS7]

Hi,

Here's my install.

Finished it in Dec. 2012.

12 x 250w panels, Midnight Classic 200, 4 x 260ahr 12v batteries (48V bank) & 3000w 240V inverter

Very low usage, about 500w average.

Runs fridge/freezer, freezer, TVs, PCs, internet & phone connection. Also some lights and GPOs in the garage.

Reduces grid usage and allows more export from a 1900w grid-connect inverter.

After the Solar production stops, it will run on battery until it's down to 50V. A NC relay, controlled by the Classic, switches the grid supply to the inverter off at 54V and back on at 50V. Hopefully that will give a good battery life. I've found we can run between 3 - 7 hrs., depends on whether our grand-children are here (early night for all if they are). The inverter will supply the load and hold the batteries at 50.7V, so not too much charging happening.

I like to keep a good reserve in-case the grid is off for any reason. Saves missing recording those important TV shows!

dRdoS7

[dgd]

So the main loads are the fridge/freezer and freezer, the other loads would not amount to much..  The 3 to 7 hours is  the limit due to battery capacity?  You are probably only another set or two of those batteries away from being off-grid completely 
dgd

[dRdoS7]

Hi,

I did have thoughts of going off-grid. I worked out that I could have pay-back for the current system in about 7 years. My calcs rely on me exporting to grid from my other system, which we use less of now.

We have few other items like AirCons & Oven which are intermittent and large use (relatively). I'd have buy a genny, and/or larger inverter, and more batteries. It just didn't make much $$ sense at the moment. I'd also have to make changes to the existing wiring, which I don't want to touch. My "Solar/Grid Hybrid" runs totally separate circuits which I installed in 2008 when I was running off a UPS. I did this as protection against the occasional black-out which caused our Digital TV Recorders to lose their time setting and not record, very annoying to the wife.

Still, in the future when I have to replace the batteries or the price of electricity has gone up 200%, I may re-assess.

dRdoS7.

[dRdoS7]

Hi,

Still, in the future when I have to replace the batteries or the price of electricity has gone up 200%, I may re-assess.

One of my AGMs has failed, after not quite 4 years.

Choice was LiFePO4 or NiFE. Same total price for a 48V 200ah bank.

NiFe won. I hope I made the right choice, or I am a dead man!

Ordered yesterday, delivery expected in 4 -5 weeks.

I calculated that the current systems have saved us just over $8500 (inc. reduced usage Aug 2010 to Dec 2012, no payments for electricity since Dec 2012 + rebates for feed-in). The total cost was $12,500 (1 in 2010 & 1 in 2012).

dRdoS7

[dgd]

So why did you choose NIFE instead of LiFePO4?
If cost is not a factor then I would have thought the more compact maintenance free greater DoD usage of LiFePO4 would have been the choice.
Just the maintenance and water usage of NIFE would have made them less attractive for me.

Dgd

[mike90045]

The water usage with NiFe is rough, but you cannot make a mistake and kill them. 
( ok, don't use them for target practice )
 but the worst drawback is the 5 year electrolyte change out.  That's going to be a mess.

[dRdoS7]

Hi,

NiFe require less electronics (ie. no more than I have now) to look after them, and as you say "Hard to Kill". LiFePO4, on the other hand, require balancing, LVD & HVD, and can be killed easily, though it probably would require the user to be a complete fuc*wit to do that!

I have read that they don't use much water, and electrolyte doesn't need to be changed that often. I will be running them within narrow voltage limits (43-59v), due to my inverter, so they won't be getting overcharged. I may lose some KwH, but shouldn't have water loss problems.

I'll post back when I've got them setup & running, and again later, when I see how they are performing. 12 months use should give me an idea on water usage at least.

dRdoS7

EDIT: I also managed to sneak a WbJr through at the same time. Actually ordered it in advance of buying LiFePO4, and not "really" required now, but I'll be able to monitor usage better now.

[russ_drinkwater]

What breed of inverter are you running?

[dRdoS7]

Hi,

What breed of inverter are you running?

One of these: http://www.mppsolar.com/v3/pip-lu-series/

Still waiting for my batteries, apparently there was some delay (duh!), and they have now passed through customs. I think he didn't order them as early as he said. Talk about a slow boat from China.

dRdoS7

[CDN-VT]

important TV shows!

Really , Not over here !!
Maybe Auzi


Nice work !

[russ_drinkwater]

Had a quick look appears to be a taiwanese made inverter.
One of my mates runs one and swears by it.
Often thought about getting one for a secondaary backup or for my mothers riser chair in case of blackouts!

[dRdoS7]

Hi,

important TV shows!

Really , Not over here !!
Maybe Auzi


Nice work !

AFL & Cricket for me.

I assume you meant Aussies/Oz.

Plus, my wife has become hooked on the Yank Pawn (not Porn), and House Renovation shows.

dRdoS7

[CDN-VT]

Aussies/Oz

Yes , So AFL is American Football ?
Cricket yes <i see

Im a F1 dude . Webber & Smiley now  Mr Daniel Ricciardo

VT

[russ_drinkwater]

F1 is a 9mm submachine gun used by the australian army!

[RossW]

NiFe require less electronics (ie. no more than I have now) to look after them, and as you say "Hard to Kill". LiFePO4, on the other hand, require balancing, LVD & HVD, and can be killed easily, though it probably would require the user to be a complete fuc*wit to do that!

I've only been running LFP (LiFePO4) for 2 1/2 years so still fairly "new" at it.
I don't have "extra" LVD - my inverter has a minimum voltage and it will cut out if I ever get to that. (I never have). None of my loads draw directly from the batteries, so if it doesn't go through the inverter, it doesn't go.
Additionally, the inverter will call for the generator to run if it gets below a set SoC, or voltage. My LFP have never got close to the minimum voltage.

For maximum, the charge controller has a maximum cutoff too. I do have a small set of balancers (charge-shifting devices) - they can move a maximum of 2 or 3 amps, which is enough. Even without them, I would be fairly comfortable running with none - and just a cell *MONITORING* system for a few bucks... it can call me if things are getting whacky.

NiFe wasn't going to work for me last I looked, because of the huge range in volts between discharging-but-still-ok and charging-but-not-yet-full. The old inverter wouldn't handle it, but some nowdays will.

I have read that they don't use much water, and electrolyte doesn't need to be changed that often. I will be running them within narrow voltage limits (43-59v),

That's "narrow"??  (My LFPs don't get below 51V or over 56.5V)

I may lose some KwH, but shouldn't have water loss problems.

That's the other thing that I considered. I don't really have enough PV for winter and run the genset a fair bit.
Cycle efficiency of 95%+ for LFP means significant running cost savings over even lead, and NiFe are less efficient again.