Kid-Classic communications

[EW Zuber]

I am about to add two more fixed array's to a 1KW Classic 150 installation. I need to know if these Kids will limit current as instructed by the classic.
Also I need to know if there is mode synchronizing between them yet. (bulk / absorb / float)

[Westbranch]

the KIDs have a max Amp limit of 30A...  were you hoping for more?  Don't know about FollowMe...

[EW Zuber]

I was kinda hoping for more communications yes. If the Kids could communicate with the Classic then I could size the array larger and not worry about overcharging the batteries and use a Whiz bang Jr. to compensate all three controllers for load usage.

[tecnodave]

Kid-Classic communications is being worked on but not here yet. You will not have to worry about overcharging using more than one controller provided that you have entered in the correct voltages in both units, lack of direct communications will result in non equal load sharing between the controllers but this should not cause overcharging.  Classic follow me style will cause all controllers to be in the same mode, bulk, absorb, etc,  but does not necessarily force equal load sharing.

I am using up to four controllers on the same system at some times , two Classic 150's and two Kids
Load sharing is sometimes a problem and I need to do battery voltage tweaks to get a better balance and equal loading on each controller,  Overcharging has never been a problem, I am usually floating by noon as I am very over paneled for sunny days but I am right on the edge of that big pond....the Pacific Ocean so I get real extreme weather sometimes for 10 days and more. Lots of fog and deep marine layer......1000 feet of stuff on the deck.........have not run my generators in a year for battery charging thanks to my MidNite Controllers and other gear.

David

[EW Zuber]

Dave, when you say that you sometimes have problems with load sharing are you saying that one array might not output full power to the batteries when it could be?

[EW Zuber]

I'm also wondering if I can use a common negative lead from the panels to the Kid without causing a problem. Some controllers can't handle this.
Just trying to save the customer a few bucks in wire.

[tecnodave]

Ebzuber,

Second question first,   No you cannot use a common negative wire from the solar arrays when  you use two kids on the same system, the Kids measure current on the negative wire so needs to be directly connected from the controller to the panels,(both positive and negative), pretty clear in the manuals. There is a mode that was called bully mode that basically put one Kid as slave and one as master, but I think that is not in current firmware. There is twin mode but my very early beta kids do not have that

Now the question on load sharing,  when in bulk MPPT mode, the sharing is ok, the panels arrays will produce same output within reason, not exactly equal, however when in absorb one controller will be outputting a higher percentage of that array's power than the other controller.....BUT....this is not a problem as the batteries cannot accept the full output of the controllers at this time, the controllers should be out of MPPT mode and limiting the output. I have this happening, to make a bit more equal I go to tweaks and offset the battery voltage on one controller or the other to get a more equal load balance.  (Between the controller outputs) no it is not plug and play.....I messed around for days to get tweaks set up for balance. I tweak by +/- .1 volt at a time on one controller at a time, then let it run for a while.  My balance factor is to harvest the same % of full power on each array! they are identical panels on each matched pair of panels.

12 Sharp NE-165/NE170  72 cell poly crystal panels on each Classic
2 Suntech 280 watt 72 cell poly crystal panels on each Kid

On sunny days I don't even tweak the Kids, the classics provide more than enough to fully charge and run huge loads, I get 2000 feet of pea soup fog marine layer in the summer so everything needs to the maximum, I've seen two weeks with no sight of the sun, then I will be checking tweaks every day.


Dave

[EW Zuber]

Thanks for the info and clarification Dave.  I believe I read that there is also a 'follow-me' mode for the Kids also.
One array will be due east the other south so there probably won't be much conflict with power output.