TalkBaja.com » Baja Mexico Forums » Off-Grid / Solar, Wind or Generator?

I was just curious if anybody here has seen an off-grid setup running two inverters off one battery bank? As we are in the process of building the garage and my workshop, I am thinking that I would like to have a separate inverter just for my shop that could be turned on/off as needed, working independently of the household feed / loads.

I appreciate your input and open to any other ideas...

Ron, we run 2 Outback inverters, one is the primary the other is wired as the slave unit. I have never needed to turn on the other one as the Outback can handle up to 3500W continuous, and up to 4800W for short periods.

The master / slave relationship on inverters is for two inverters feeding one circuit panel, correct? I was thinking of wiring the garage-workshop via a separate circuit panel via an inverter feed that would probably just be turned off at night. Any downside to that???

Seems like if you use an identical unit for that then you will have redundancy/easy to swap them out...

when one croaks.

Originally Posted by Marty Cortez

Seems like if you use an identical unit for that then you will have redundancy/easy to swap them out...

when one croaks.

That was something that was on my mind in all of this. People who have been doing the off-grid thing for years tell me that the wink links in the system that will certainly fail at some point are:

1 - Batteries
2 - Inverters
3 - Charge Controllers

I am trying to build my system in a way that gives me greatest flexibility, ease of access/repair and operation. I split my solar panel feeds through two Xantrex MPPT XW60 units. That way if one should fail I can simply move solar panel feeds over to another unit - something that is quite simple in my current setup.

Batteries will fail eventually but if maintained the decline is usually slow, giving me time to prepare and shop around. In the worst case if one should crap out I can simply isolate that loop and just drop my bank capacity a bit to get through.

Currently I have no back up plan for the inverter (other than two gas powered generators) which was part of the reason I was thinking of this type of inverter setup.

FWIW: I can't see how it would be problematic.
Kind of like two pipes from a reservoir. Capacity is the only concern I can think of.
But, it is early and I am only on my first cup of coffee.

Originally Posted by soulpatch

FWIW: I can't see how it would be problematic.
Kind of like two pipes from a reservoir. Capacity is the only concern I can think of.
But, it is early and I am only on my first cup of coffee.

My system battery bank capacity is currently 1320 amps at 24 volts. According to my Bogart we never go below 95% SOC up to this point.

I hear you on the coffee thing - I don't like to even make a decision on what socks to wear in the morning without at least one cup first...

I also use 2 Outback inverters probably similar to Astrobaja's setup. I have them in paralelle (sp?) which means the master inverter is awake all the time and the slave inverter sleeps until it senses a load requiring its help and then it wakes up and supports the master inverter. No need to turn one on and off it is all done automatically. Another advantage to having this type of setup is that I now have at my disposal 5600 watts of power so no need to run the generator if I want to do some welding or run the lathe. When I turn on the larger equipment the inverter just wakes up and handles it.
Hope this helps
Larry
PS Any luck with Jason?

Originally Posted by rplarry

I also use 2 Outback inverters probably similar to Astrobaja's setup. I have them in paralelle (sp?) which means the master inverter is awake all the time and the slave inverter sleeps until it senses a load requiring its help and then it wakes up and supports the master inverter. No need to turn one on and off it is all done automatically. Another advantage to having this type of setup is that I now have at my disposal 5600 watts of power so no need to run the generator if I want to do some welding or run the lathe. When I turn on the larger equipment the inverter just wakes up and handles it.
Hope this helps
Larry
PS Any luck with Jason?

I suppose that such a setup would require two identical brand inverters, correct?

I will be contacting Jason on my next trip up north so we'll see what happens...

Yes, it would require 2 identical inverters. Most of the higher end pure sine wave inverters are capable of being stacked. The way your are proposing to do it will work just fine. you just won't get the combined power of the 2 inverters together. No big deal. My slave inverter hardly ever comes on.
Larry

For heavy loads like the cement mixer / welder I just fire up the Yamaha generator. It needs to be run once in awhile anyway...

Here the diagrams from Outback
http://www.outbackpower.com/pdf/wiri...120-240vac.pdf
You get two 115 V circuits and they can be used as separate circuits or can be combined , as in your 2 phase housewiring to create the 230V . You can even stack 3 and get 208 V three phase. All the wiring diagrams at
OutBack Power / Resources / Documents / Wiring Diagrams

I'm all for redundancy, I have two 3648 Outbacks, two Outback charge controllers and split my solar arrays into two banks. I think it would be easier to just "stack" the inverters as someone mentioned since the "slave" will be idle 95% of the time and just turn on if/when needed. If the "master" inverter did fail, it is simple to program the other inverter to be the master and off you go.