What I have seen Scares me

[Herman]

Good Evening Guys

I have a friend on who has been on solar for a while and had the same installer as I had  he has 40 Nife 1,000 AH Cells with  with 2 have been sitting dormant as in not attached, no MPPT controlling his panels which are going straight in to the batteries which are DCH-BX65 in 2 series 28 panels no earth stake no arc fault protection and he also installed TSMC CIGS x 3 series 3 parallel 160w thin film panels also with no mppt.

now this is from a installer that knows everything.

My Thought he should drop 6 BX 65 panels install either a classic 200 or 150 MPPT which the string size tool recommends and either take the TSMC CIGS out of the equation or set them up  parallel to and MPPT to the same bank (not sure if that works) your thoughts.

[Westbranch]

Can you tell us a bit about his loads too...  That sounds a lot scary, not just a bit...

[Herman]

This Guy Runs a Teaching Farm

I can only guess what his loads are but i know he runs the normal lighting about 5 fridges (would like to run a cold room) Electric welder water pressure pump three possibly four TVs air compressor a office and all its computers and printers the loads do vary from time to time depending on seasons and if he has classes in.

As i Pointed out to him he has all this power going into his cells what is controlling the power when the sells are full the real scary bit the supposed installer has put the inventor in the same room as the 40 Nife Cells then demanded that he also have an extractor to take out the fumes, I thought to minimize the risk no electrical or anything that may cause sparks anywhere near the batteries.

I would love to have the knowledge to put it all together and help him as his system and the way it is setup is scary and i think it would be better for him to have one of the reputable Coy's deal with it and fix up the the areas that he needs, like http://www.rpc.com.au/

[mike90045]

I've got the 800ah NiFe cells, and in float, no loads, the batteries suck about 900W off the PV just to stay in float.
So he is likely going though a lot of distilled water (I just did 8 gallons today) but if the batteries are not heating up from the power, they are not being hurt, as long as he can keep up with the water.

It would be fun to shoot a IR thermometer at the panels at night to see if there is any backfeeding happening.

[Herman]

Ill Do the IR thermometer as he has one and post it 

[Herman]

Sorry Mike ignore my last comment

In reference to back feed they turn of the panels at night to stop it. when I found that out I just shook my head and I explained my thoughts on the supposed expert that installed both our systems. That is why I have showed them the Classic String sizing tool and the MidNite Web Site  so you will probably have some new forum members soon who will be asking heaps of questions and as they have seen my Classic 150 are very interested in getting one that would be suitable for there needs. I'll keep you posted 

[dgd]

Sound like the installer knew  what he was doing. NIFE cells are a lot more robust electrically than most other higher charge density cells. This means they can take what would be described as abuse with other cell types. Charging times and set points are not as critical, neither is discharging and charging regimes. I have actually seen 100% discharged, dead, NIFEs brought back to life, you will not do that with a dead lead acid battery.
A human in attendance switching off the PVs to prevent overcharging and backfeeding is the simplest type of controller (although backfeeding could be resolved with a decent size blocking diode).
Doing nothing, apart from watering, is probably also a valid NIFE/human controling regime.

There is an excellent wiki on NIFE, Edison, cells. Reading that may help alleviate being scared 
An MPPT controller is, IMHO, not essential to charge NIFEs properly, neither a taper charge PWM type controller and perhaps a simple on/off controller would be useful if the human is too busy or forgetful.
Perhaps a trained chicken would do, cheap to run on suitable provender 

dgd

[Herman]

Thanks dgd

I have quiet a bit about Ni-Fe cells being brought back from death and seen one of the masters Thomas Edison's cell at 85 year old being brought back that was one of the reasons I choose them with my friend though he uses quiet or should I say heavy usage with cold rooms, butter and cheese rooms, the other reason for the use of the MPPT's AUX function would be to start a diesel generator and turn it off mainly due to the reason he runs an instructional permaculture  farm and solar being one of the subjects my thoughts would be a complete working system.

As he students change all the time and as they are responsible for the management of the system before even having an understanding of it may be a bit much to ask and IMHO I think it goes over his head like a jet fighter as well