Author Topic: OFF GRID POWER; various thoughts on...  (Read 445690 times)

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Offline MountainDon

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Re: OFF GRID POWER; various thoughts on...
« Reply #1450 on: May 08, 2018, 03:50:26 PM »
Is the generator used as a portable device? No permanent connection between it and the battery charger?
Is the generator output also connected to any cabin wiring, service panel, etc?

Is the power output from the inverter used directly via plugging into the inverter AC outputs?  Or does it feed into a service panel of any sort?


Looks like maybe a 12 volt battery system?  The distance between batteries and charger and batteries to inverter would be less than 10 feet? #4 AWG wire would be more than adequate.

No PV panels?  No charge controller?

The fuses should not be in the same enclosure as the batteries just in case one blows when hydrogen is present in a combustible mix, unless the fuses are fully encased to keep the arcing within a shell. A fast-acting class T fuse is best for use in a DC line connected to a battery bank. They can be mounted directly to a battery or in a case. Others may have to be mounted in a case to contain arcing. Fuses / breakers must be rated for DC use when used in DC circuit.
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline Beavers

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Re: OFF GRID POWER; various thoughts on...
« Reply #1451 on: May 08, 2018, 04:28:11 PM »
The generator will pretty much permanent in an enclosure. Battery charger is an Iota plugged into the generator.  No hard wiring of the generator to the cabin.

For now I will be plugging into the inverter to run a fan and charage phones.  When I get a bigger inverter it will be connected to a service panel.

Yes 12 volt system...battery bank is four 6v golf cart batteries. Will be 5 foot from batteries to inverter.

No pv panels or charge controller yet.

I got class RK5 time delay dual element (FLNR 50) 125V DC fuses.  Will those work?

Thanks for the help!

Offline MountainDon

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Re: OFF GRID POWER; various thoughts on...
« Reply #1452 on: May 09, 2018, 09:54:07 AM »
Generator.  Used as described it more or less is much like using a portable generator on a job site to power tools. According to OHSA regs that does not need a ground to earth.

Inverter. Used as described it would be as intended, more or less a portable device. No need to have an earth ground. Things change when a service panel is introduced though.

House wiring, done according to code, has a bond of the neutral and ground at one place in the system. That is usually a green screw that bonds, or connects, the ground and neutral within the service panel. If you connect a MSW inverter to such a system, the MSW inverter will be toasted, the magic smoke is released and the MSW inverter is no good anymore. It seems odd to me but any MSW inverter I have checked out has 60 volts between ground wire and neutral and 60 volts between hot and ground. Add those up and you have 120 VAC. But introduce a N-G bond and you produce smoke.  PSW, pure sine wave, inverters designed for hard wiring should not have an internal bond and should be okay wired to the typical bonded service panel. I don't know about PSW inverters with built-in outlets. ???

Small portable generators with built-in outlets,  often have the neutral conductor bonded to the generator frame, which equates to a neutral-ground bond. In that case, when the generator is connected to a service panel there should NOT be a bond in the panel.  My Honda EU2000i is one w/o the internal bond. But the Honda EB200 does have a N-G bond. It can get confusing.



Fuses. I'm not familiar with the ones you mentioned. The idea of the fuse is to protect the wiring, not the charger or inverter. A lead acid battery can supply thousands of amps with a short circuit. If the time delay is too long the wiring could be damaged.  Time delays are most often designed for use with circuits that power motors that may have a large startup surge, then fall to normal ranges. So I can't say those are good or not.

The NEC used to exempt 12 volt systems from needing a ground to earth; higher voltages required an earth ground of the battery / DC negative. 

Once PV panels are installed that has some rules too. PV systems are now supposed to have a GFP (ground fault protector).  And with panels the lightning issue can become a serious concern and will need protective devices and good grounding.

I am not an electrician so take what I stated above as a place to start your own research from.
« Last Edit: May 09, 2018, 10:40:29 AM by MountainDon »
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline Beavers

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Re: OFF GRID POWER; various thoughts on...
« Reply #1453 on: May 09, 2018, 03:26:22 PM »
Thanks Don.
My Ryobi generator has a "neutral floating" ground lug on the front. I should probably start with reading the manual to see what it says.  d*

I double checked the specs on my fuses. I got them from AltE it says they are good for inverters up to 700 watts so I think I'm good there.

My electrical knowledge is very little.  One of the big reasons I'm starting with such a small system. I'll definitely continue reading up and learning more.

Offline Dave Sparks

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Re: OFF GRID POWER; various thoughts on...
« Reply #1454 on: May 16, 2018, 06:51:43 PM »
Is there a solar charge controller? I probably missed this as it is changing before my eyes d*
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Offline Beavers

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Re: OFF GRID POWER; various thoughts on...
« Reply #1455 on: May 16, 2018, 06:55:52 PM »
Nope. No solar yet. I'm a total electrical novice...so I'm starting very basic and slowly working my way into things.