Twin mode

[Bunkie314]

So I'm assuming that "Twin" mode has replaced "Bully" mode, stated in an earlier post that has gone off to serial data communication. Twin 2 generates more heat, 5 to 10 °C more temperature with the screen saying less output than the master. The master also programs battery amp limit down to 15 amps and defaults to O&P solar when you connect them or if the twin is lost due to an error. Is this normal? What solar mode should be used? Both solar and solar2 seem to work well. Outputs don't agree with each other and sometimes they are 80 to 100  watts different when above 250 watts output (@12 volts), twin 2 is always lower output and running hottest temperature wise. Is this normal? I've also noticed the battery and input voltage differ between each unit of which I have calibrated before placing them into service. To get them to agree I have calibrate each unit while in operation together, I'm assuming that is okay. Wattage output between the two are more in agreement doing that. Twin two is still running at least 5 C hotter, up into the 50+ C range, with only 15 amp output (30 total) in bulk charge.

So I have the following questions/comments below:

1. What solar mode to run in twin mode, there was a post somewhere to use solar2 I can't find now. Can solar be used?
2. Is it normal for the twin 2 to run that much hotter than the master? I've seen 10 C difference in bulk charging.
3. Should the battery and input voltage be in agreement on both units when in twin mode operation? Or does it matter?
4. Twin 2 locks up sometimes, seldom, with the squares just on the top line of the display. I haven't determined why yet.

FW 1791
544 watts PV connected @ 88 VOC, ISC 4.1 for now,  I will connect full Wattage of 1360 once I'm comfortable with it
12 volt setup, 630 Air capacity

[Mario]

Bunkie,
Twin mode has to be wired with special care to get both units to share the currents correctly.
From the point where the wire splits to both units it has to be close to the units and the same length and same awg to both units and close to them is best results. Also the torque has to be the same for both units. PV and Battery connections.

You need to download and install the latest firmware available 1797.

After the installation you will need to do a factory reset on both units.
before you input any parameters both units have to get synchronized like this:
-do factory reset on twin1 and when it comes up for the first time and does a search turn the power OFF
-do the same on Twin2
-now turn on both units On and they will search for each other (Must have the Comm cable plugged in )
-On the unit you want to be in control (you pick Twin 1), select Twin and press Enter, the other will automatically get set to Twin2
-both units will now go to the menu where you select the battery nominal.
-set up Twin2 first, finish the set up until menu says "DATA HAS BEEN SAVED"
-Now set up Twin1 the same.
-after the set up turn OFF all power to both units and turn them ON at the SAME time they should reconnect automatically.
-turn ON PV power for both units and they should be charging.


Note: Twin mode only works on Solar 2 mode. Twin 2 will say Solar but it is working on solar 2 mode internally.
- Wiring is really important for this mode to work correctly.

Mario

[Bunkie314]

Mario,

Both units are mounted together, stacked top/bottom, with identical length PV and battery leads (pos and neg) from the combiner box I am using.  I went equal lengths on everything to ensure a balanced load to both kids. Leads (8 ga) are only 24 in long on PV and batt. And yes I cheated and removed three/four strands on the kid side to get them into the terminal blocks. FW is actually 1761, not sure how I missed that mistype.

I'll get the update installed and check all connections this weekend.

[Bunkie314]

Updated firmware, did a factory reset, checked all connections and noted the following:

1. Kid 2 will display amber light after some time that charging has not been completed.
2. Anticlick sensitivity setting doesn't seem to be very responsive, will not go to rest mode in low light evening time frame and draws almost 1 amp from batteries until it finally determines to rest. My location this can take over an hour.
3. It seems to want to run 10 volts lower than Vmp, always runs 56 V vs 66 V.

[Vic]

Hi Bunkie..,

Only have one comment;

STC Vmp is with Cell temperature of 25 degrees C.  In the sun,  the cell temps are 20,  to roughly 40 degrees C higher,  depending on the ambient temps,  sun intensity,  wind,  etc.

So around midday,  it would not be too difficult to expect string Vmp to be below STC string Vmp.

You might be comparing the difference between Vmps in to a single KID vs Twins,  but even that can vary considerably with angle of the sun and temperature of the PV Cells,  and so on ...   FWIW,   Vic

[Bunkie314]

Vic,

Comparison made within moments of each other.  I've tried to rule that out by switching between modes quickly to compare. I should have stated solar mode runs 10 volts higher than solar O&P IN TWIN MODE consistently.

[Vic]

OK,  thanks for the info Bunkie,

Thanks for giving Twin mode a run,  as,  this is how MN makes things better and better (stating the obvious).

Have Fun,  and good luck,   Vic

[Bunkie314]

Eq doesn't work if the system power hasn't been cycled recently. Can't narrow down a time frame, but does not work if the systemhas been running for any length of time  (I'd guess 4 weeks or more)

Also is the EQ temperature compensation ever going to be addressed? My betas never have worked even toggling yes in the menu.

[Halfcrazy]

Bunkie
I will be wiring KIDs up in Twin mode here this week. I have done it before with success but the firmware has changed and I need to become familiar with the KID.

If you want to email me off list it may be easier ryan@midnitesolar.com