Need help with battery back up system

[misfit138]

Hello Im new to the forums. and have a few questions

Heres some info of what i have,
I have a 6.8 solar system, 40 BP panels at 170 watts each and a sunny boy 6000 inverter. The system was installed about 5 years ago and is grid tied and i have been looking to hook a battery bank incase of power outs.I would like to be able to switch back and forth from batteries and grid tie wither it be automatic and or manual if at all possible. I live Close to the shore in New Jersey, ( so im sure you have heard what hurrican sandy did and its not a pretty picture) And this is why i would like to get started on a design and get movingon what i would need. I am a machinest and welder by trade so making things comes pretty easy, my down fall is electronics so any help would be appreciaed. also in the near future i would like to do a small windmill so id like to hopefully be able to tie that in somehow. I know batteries are expensive so i will start off small and  in time add more to increase power.

Thanks In advance. 

[mtdoc]

Unfortunately, it is not so easy as just buying batteries and adding it to your system.   In order to make use of your existing Grid tie system, you will need a charge controller and another inverter as well to do what is called AC coupling.  SMA makes the Sunny Island inverter which will do this and I believe Midnite has a brand new pre-wired epanel that uses this inverter.  Doing this will not be cheap. It is also fairly complicated - though Midnites epanel will simplify it somewhat. 

Have a look at SMAs website info on their Sunny Island inverter for more details. I'm sure someone from Midnite can chime in here and provide more details about their Sunny Island epanel.  Here is a link to the Midnite brochure.

[misfit138]

Thank you for the reply.Unfortunaly i know its not as easy and dropping a lot of batteries in and was pretty sure i would need some sort of charge controller and inverter, my problem is knowing what is good and what is right and just not buying a bunch of s**t and it not working or getting the wrong parts and i know as with any diy project theres always those little unforseen things like connectors, specific wire etc. I will look into the sma inverter, and the link you put in does not fully load. will try and figure it out. I know Its gonna be pretty expensive, but id like to see how much and maybe start getting some pieces here and there.

[TomW]

misfit;

i know its not as easy and dropping a lot of batteries in and was pretty sure i would need some sort of charge controller and inverter, my problem is knowing what is good and what is right and just not buying a bunch of s**t and it not working or getting the wrong parts and i know as with any diy project theres always those little unforseen things like connectors, specific wire etc. I will look into the sma inverter, and the link you put in does not fully load. will try and figure it out. I know Its gonna be pretty expensive, but id like to see how much and maybe start getting some pieces here and there.

Just like automobiles, you will get a lot of preferences from individuals.

Personally, I have had stellar luck with Midnite Solar and Outback on support and warranty service.

Not so good with the Trace equipment I had issues with some years ago. I have released the magic smoke from quite a lot of that cheap Chinese gear you see cheap on FeeBay and wish I had just went for good stuff up front as it would have been cheaper in the long run.

If you want top shelf equipment both Midnite and Outback seem to fill that need. Good gear costs real money but you get what you pay for. I hear you on the miscellaneous bits of a system, I usually don't really know what I need til I need it and here in the boondocks you can't just go to the downtown big box home store or the RE store and buy what you need because we only have small town hardware stores and Wally World and they do not stock anything like that.

You might want to upgrade to an inverter that does the whole grid tie with battery backup rather than piece together a hybrid system with multiple inverters. Less pieces to try to get to work together. Frankly, I am not sure who makes such an inverter but I have heard they exist.

Just sayin...

Tom

[mtdoc]

Agree that Outback and Midnite equipment is great. I have an Outback grid-interactive inverter on a Midnite epanel myself and am very happy with this setup.

But SMA is absolutely top notch German engineering.  Adding the Sunny Island ePanel to tie into your existing Sunny Boy inverter in an AC coupled system would be one very high quality way to do it.  You could also do a twin stack of Outback GVFX3648 inverters (and perhaps sell your used Sunny Boy inverter?).  I'm not sure which would be most cost effective.  One thing to keep in mind though - if you went with a twin stack of Outback inverters you would likely have significantly less efficiency in selling back to the grid than you do with your Sunny Boy.

BTW not sure why the Midnite Sunny Island link is not working for you - it works fine for me.