Connecting a Midnite controlled array to a Sunny off-grid system

Surfpath

Hello Folks,
I am back online after a little busy period in life. Glad to see the forum well and alive.

I now helping another off gridder who has a Sunny Island/boy set up (yes, yes, I know there are concerns about the SI/SB off grid set up - I would not do it my self, but there we go, the equipment is there)

Here is the basic situation:

Existing set up: Sunny Island 5048, Sunny Boy 2400 (I think), 2400watts of panel, Bergy XL1 windmill, new 640amp hr bank awaiting the addition of....

1,500 watts of new PV (6 x 250 grid tie panels) being controlled by a Midnite 250. The new panels are being added to 'balance' the system during low wind times.

and the Basic problem:

The Sunny charging formula is plain nuts to me as an Outback user (though perhaps others see it as exotic and sophisticated). However you choose to view it, and I don't want to get into a debate about it.....

can the two controllers work together to charge this bank? I am aware that charging parameters (ie voltages for "Absorb/Float", or "Boost/Full", plus Absorb/Boost times) need to be the same for both units charging the one bank, right???

Several members on this forum hinted that it would be OK to do this, but I am starting to have questions.

In other words, can the exotic German Sunny speak with the good old Midnite boy??

Iz zat a problem y'all?.

Vic

Hi Surf..,

I know nothing about the SMA SB/SI products, or this Comm Adapter from MidNite, but, FYI:
http://www.midnitesolar.com/pdfs/10-269-1_Rev_A_Communication_Adapter_Manual_preliminary.pdf

FWIW, Good Luck, Vic

softdown

"MidNite Solar’s Communication Adapter is a software protocol converter for creating a communications
link between SMA’s Sunny Island inverter and MidNite Solar’s Classic charge controllers, which allows these products to work together as a system. Translating Midnite Solar’s communication protocol into SMA format, and vice-versa, allows up to four Classics to communicate with a single Sunny Island inverter. "

Looks good...its a Midnite product.

Vic wrote: »

Hi Surf..,

I know nothing about the SMA SB/SI products, or this Comm Adapter from MidNite, but, FYI:
http://www.midnitesolar.com/pdfs/10-...reliminary.pdf

FWIW, Good Luck, Vic

Surfpath

Yes, may be helpful. Here's a question though....can it enable the Midnite controller to tell the Sunny Island how to charge the bank? I am no expert, but I instinctively find the Sunny charge profile to be sub-optimal.

I'd much rather the Midnite to be in charge. Possible?

Vic

Hi Surfpath,

Just from reading the introduction in the Manual, Linked above, it appears that the SI is always in command of what it thinks should happen. To me, appears that the Classics are slaves.

The Comm Adapter may have other capabilities ... have never used one.

Here is a probably the best place on the MidNite Forum to ask that question:
http://midnitesolar.com/Forum/index.php?board=20.0

FWIW, Vic

Surfpath

Thanks Vic,
It does appear that the SI is always in command - and I am not sure this is a good idea.

An update is that we have figured out the SI control panel a little more (at times a challenging experience), however... 

The installation date is approaching and I am still unclear on how my buddy is to proceed.  The plan is to mount the 6 panels in one series (that OK for a 250v Midnite Controller) and then take the terminal 10awg (+) and (-) leads (60foot run) to a Midnite big baby box with a midnite DC circuit breaker and Minite Lightning Arrestor.  Then to the Midnite charge controller.  Then from the charge controller to the existing 48V battery bank terminals.

The thing is: It'll be impossible to match the Midnite to the SI charging profile. The latter is just too variable. 

So what charge settings do we set for the new Midnite controller?  My instinct tells me: Use the Absorb and Float voltage settings for the Trojan RE-A's plus a conservative absorb time of just 2 hrs, then monitor it over time??
-SP

ps. Random factoid that may be of help, the Bergy XL wind turbine has a Bergy (really Chinese) combined charge controller with small dump load.  It also 'brakes' when the batteries are full.  

June

Surfpath, I'm facing an identical issue, all my components are the same, even the Bergey, so I would be really grateful if you could keep me informed as to how everything went.   I'm not doing the installation (of the 6 extra panels & Midnite Classic)myself but I think it's important for me to understand what needs to be done, especially as I live in an area where installer expertise isn't up to much.   I didn't order a Communication Adapter but from what I am now reading I think I need to.   Any advice you can give me would be appreciated - my installation is due to start on Oct.26th so I have a little time to order any additional items that may be necessary.   Thanks