questions to those living offgrid with battery/inverter...

[Chris]

Inverters with bonded ground/neutral and some without bonding.

I live off grid. small solar system. mostly gen and batteries. Had a trace sw2512 but after two fixes at plus $1800 I gave up on it. I now have a small 1000 watts modified sine wave trace/xantrex. It works quite well although at bit small and it makes the house fans hum. Going to upgrade by system when $ allow.

There was an article about bonded ground neutrals some where. Ground and neutral should only be bonded in one place in a home setting. At one time I had my head around this grounding to neutral and the theory behind it all, but my brain went dead on the issue, and cannot explain why any more. If someone can shed light on this it would make a good post. My trace sw was ok when hooking up to my main panel,( neutral bonded to ground in one place) but with the smaller zantrex, my home neutral/ground connection had to broken or the inverter(s) would smoke. Yes I had my share of smoked inverters. Many smaller inverters do NOT want the ground and neural to be bonded.

A post by someone in the know on the neutral/ground issue would be a great help to those going off grid.

Thanks,

Chris
Schooner Bay Abaco, Bahamas.

[BruceM]

The grounding system is for safety, to provide a path for fault (shorts) to fail.  It should never be carrying current.

If neutrals are connected to grounds, except at the main panel, you have a code violation, and often, elevated magnetic fields which will change as the neutral is shifted by loads.  (Assuming metalic water pipes and such also bonded to earth.)  

Jens said "the only way to assure this is to have a single ground point that is used for every electrical load."  This is correct, and I would add, you may add a ground rod to distant points of the grounding system, like a sub panel, just DO NOT CONNECT NEUTRAL AND GROUND together except at the main panel.

Insanely, the Wye power distribution system uses multi-point grounding (earthing) of the neutral conductor, and jumps the neutral around your transformer, so that NO PART OF THE WYE SYSTEM IS TRANSFORMER ISOLATED.  This causes a 100x-1000x increase in magnetic fields running through the earth, and is full of high frequency content now that neutrals are being abused by low PF switching supplies and electronic motor drives. According to one power transmission textbook, approximately 25% of the Wye neutral current returns to the power station through the earth.

The Delta power system is fully transformer isolated, a neutral/ground is derived locally at the customer transformer.  Even with shared transformers, these homes enjoy extremely low magnetic fields- even with small setbacks from overhead power lines, as all the current stays on the wires instead of using the earth as a neutral wire alternate and electrical sewer.

Delta can still be found in some older US cities, but is often being converted to Wye.  Some US western states power linemen have never seen a Delta line in their lives.  When the US REA promoted power system expansion in the 40s and 50s in the US, all that work was unfortunately done in Wye.

[Chris]

Thanks for the quick response on the grounding issue. The grey matter is remembering again. For those using small inverters, be carefull about the grounding. Your inverter docs may address this. Read the docs.

Regards

Chris

[Mad_Labs]

Inverters with bonded ground/neutral and some without bonding.

I live off grid. small solar system. mostly gen and batteries. Had a trace sw2512 but after two fixes at plus $1800 I gave up on it.
Chris
Schooner Bay Abaco, Bahamas.

Chris, how did your 2512 fail? I just installed one a couple of months ago, so far so good, but I'm curious.

Jonathan

[Chris]

Johnathan,

The first go round I think its brain when dead. There is a guy here in Abaco (Bahamas)that fixed it after much trouble trying to get parts from Trace/Zantrex. This was about the time Trace was bought out by Xantrex and my fixer had a very hard time dealing with Trace. They did not want to supply the board(s) needed. After that he did not want to try and deal with them any more. I could, I guess, send the unit back to Trace, but the paper work dealing with Bahamas customs, plus shipping to California just did seem worth it. The main problem appears to be corrosion. The salty air here plays havoc with the electronic boards. I am told that the SW trace inverters are not being well supported by Xantrex so I thought I would put my $ towards, probably an Outback, when funds allow. It was a great unit while it worked. Most people in my area that are off grid, have gone with the Outback units.

My main power supply right now , cooler time of the year, A/C not required, is a Lister VA (The air cooled version of a 8/1). Which I use to charge batteries, lights, water pump for about 5 yrs per day, with a little solar.  This is an increadable machine. It has been in my family since about 1962. Lost control of it for about 6 years after our familly property was sold. It sat abandon in the gen shed for 6 years. The connecting rod bearing was just about worn out and the air cowling rusted out ,stuck injector pump, bad injector, etc. After the new owner decided it was not worth fixing and with a little prod from me, he gave it back to me. One weekend while he was away I spent about, may be an hour and had it fired up, very temporary. I had to move it by boat off the island it was located on, spent a few week ends repairing the air cooling cowling. I was able to get some new connecting rod bearings from Phil at Central Main. I am looking for a replacment crank shaft, sleeve bearing type, which is different from the roller bearing type that most Listeroids have. If any one out there knows where there is one in this part of the world, let me know. The crank has probably more than a 100,000.00 hours on it. This unit was in service at one time for about 8 hrs a day for about 35 years. A few replacements of bearings, rings, heads, liners etc. I have been messing around with this engine/generator since I was 15 years old, now 59yrs. It's my baby. It's the love of my life after wife, kids and grand kids.  There are still a few other units around here that I know of. Many with broken parts of one sort or another. I will try and locate some pictures I have and post somewhere.

Regards,

Chris

[BruceM]

What a great Lister story, Chris, thanks!

[rbodell]

The only thing I have that won't run off my 2KW cheapie inverter is my VCR in record mode so I bought a small 100 watt good inverter for that.