Energy Matters Forums

[harrydiculous]

The connectors for the Battery end. The smaller unit screws onto the M8 stud on the battery and the base makes contact with the pad. It has four tapped holes around a PCD. The top part attaches with the two brass bolts and can be located in the two of four holes on the base unit. This give the unit four positions.

The top unit has a stud to attach the spade connectors. You could also "piggy back" another top unit to add another cable.

And, of course, the hole into which the cable will be inserted & soldered.

IMGP4715 by jibbonpoint, on Flickr

IMGP4703 by jibbonpoint, on Flickr

So, I'll start sorting that today.

By the way, I found a product from ROCOL; Copper anti-seize spray. It certainly helped in the tapping. Much easier.

[harrydiculous]

Well, this is good news. The forum continues.

My own project had stalled due to competing domestic duties & travel. I've just completed improving the cabling. Now need to sort out curcuit breakers on the 12 volt side.

Goal is to be able to run the fridge & freezer at night so I'll obviously need an electrician to sort out a separate cuircuit but I'm sure I can run a lead in the meantime for a trial.

The four 100 amp hour batteries (2400 watts) probably won't do it so I'll need to buy more.

I can't find on the net an estimate though of power usage. The fridge uses 647 watts on defrost. The upright freezer gives no indication but is 1500mm 500mm x 500 mm. (375 litres). Obviously they cycle on & off.

Any idea what I need to run them at night? (3500 watt Inverter)

Thanks

[jules]

Lost track of this over what, six months and a lot depends on usage factors like how many people in the house, how many rooms and what your longterm goals are.

Regardless of the above, you're right about the batteries but you do need to approach that in such a way that you don't introduce problems into the system. I'm not sure if we've dealt with this before but batteries should be in series not in parallel, so if you want to increase the size of your storage you might have to go back to square one and buy a complete battery set of say 6 X 2V = 12V, 12 X 2V = 24V or maybe 24 X 2V = 48V using 1,000Ah, or more, batteries to suit the voltage on your inverter. You might choose to go Lithium of course. For the fridge/freezer combo you'd probably need to go to the biggest of the above sets.

If the fridge does its defrosting at night and you can't force it to do it during the day, I'd turn it off and go manual defrost. Shocking waste of power!

It's hard to estimate how much power the fridge and freezer will use but you can be reasonably sure summer consumption will be close to double winter consumption depending on all sorts of variables like house temp., how often the fridge door is left open and so on. Unless you considerably upgrade your power storage there's no way you can power the fridge and freezer. You might be better off getting rid of one if you can.

[harrydiculous]

Thanks Jules.

I worked out a while ago that I should have asked for advice BEFORE I started work. The Inverter is fixed at 12 volts. And it's created a lot of work & expense sorting the cabling and I don't think that it's right, yet.

There's six panels. 3 x 2 in series giving approx 40 volts to the MPPT Voltage regulator. 160 watts each panel.

Currently runs the washing machine easily on a sunny day and the Computer & LED TV 24 hours. All of this it does easily. If the washing (3 loads) gets finished early, then it recharges by late afternoon.

I'll be just happy if I can extend it to the Fridge Freezers. (2 adults in residence). (Hot water is solar and uses the grid solar on the house for boost).

Nothing in this is critical to our lifestyle. More of a hobby. As I said much earlier, it beats golf.

[jules]

I guess, in hobby terms, you could add massive amounts of insulation to both the fridge and the freezer. Doesn't cost much and makes them look proudly DIY.

[harrydiculous]

Not sure that "the boss" would approve.

Anyway, 2400 watt/hours available. (4 x 100 amp/hr batteries div x 2)

Say, each unit, 300 watt hours each. (50% on/off) Will last four hours. So would need another 4 batteries for 8 hours.

The four batteries do charge quickly from 12 volts to 14.4. So another $900 for another 4? ???

I would seriously look then at another $4000 for an hybrid inverter & utilise the 3000 watt panels currently installed.

EDIT to add: Or I could power just one of them. The system is underutilised at present.

[jules]

The challenge comes when you have 4 or five days where it's overcast, though I'm actually wondering if that situation might never occur again, thanks to Climate Change.

[harrydiculous]

Yes. I'd have switchable circuits. The freezer, I think, would be the one to choose. The only time it gets opened is when the bulk ice tray needs to get refilled to replenish the one in the fridge that used to supply the vast quantities needed for the massive amounts of whisky that's consumed around here.

[jaahn]

Hi Harry
Yes it is good news that the forum seems to live again.
I would think that you should be able to normally run a fridge and freezer overnight on 400Ahr of batteries. I would have to get a handle on what you have again but I remember you bought some meters to measure things before.
The combination of an inverter and ac units might be not so efficient but people do it regularly in caravans. The stand-by power use of the inverter and the efficiency when running is a factor. I guess I would say measure the power use of everything regularly to see what is happening.
The second thing is the power losses in the DC supply to the inverter but I think you worked on that. Use a voltage meter to check the voltage drops while it is running. A volt here and there soon addup to 25% loss at 12V.
Cheers Jaahn

[harrydiculous]

Yes jaahn. It seems to be running OK now. I've only got the 4 x 100 amp/hr batteries which will give me 200 amp/hr but connecting the freezer should give a very good idea on how many more batteries I'll need.

I have probably downplayed my interest by describing as a "hobby." Interest in alternative energies have been a passion for many years. I can now do something about it.

(The wind generator is a predictable dead loss.Live & learn.)