Instruction Manual

The KID Solar Charge Controller Instructions
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1 0-268-1 REV P7
The KID Internal terminal block
Wiring the marine KID
Centered directly above the ½” conduit holes you will find the main 30 amp 6
position terminal block.
This is where you will connect PV input, loads (if any), and the battery bank.
The battery bank should use 1 0AWG wire (5.26mm2). Wiring runs from the
battery bank should be as short as possible. On the included wiring diagrams
you will notice an external 30 amp circuit breaker in series with the battery plus
wire. This is very important and is a requirement to meet NEC guidelines for
overcurrent and disconnect devices. The battery overcurrent device regardless
whether it is a circuit breaker or fuse must be rated for the DC voltage rating of
the battery bank with a minimum of 5000 Amp interrupt rating.
IMPORTANT! Input, output, and load negatives must be isolated. They are not internally
connected.
Inaccurate current readings and damage may result from improper wiring.
Load Positive is internally connected to Battery Positive. Loads are switched in the negative leg.
Fuses incorporated into The KID are not to be used as these NEC required overcurrent devices.
The internal KID fuses are for supplemental protection only. MidNite Solar manufactures numerous
circuit breakers and boxes for this use.
PV input overcurrent devices should follow the NEC guidelines of 1 .56 times short circuit current. Therefore
two 250 watt modules in series results in 8.87 amps of short circuit current (Isc) X 1 .56 = 1 3.83 amps. The
NEC allows 1 5 amps through most 1 4AWG wire, so in this case 1 4AWG wire is sufficient. Long distances
(over 30 feet / 9 meters) may want to use larger wire to minimize voltage drop. Now let’s take those same two
solar panels and put them in parallel. This configuration will result in 1 7.7 Isc amps. Multiply this by 1 .56 =
27.6 amps. 1 0AWG wire is rated for 30 amps, so you would need to switch to 1 0AWG wire for paralleled
operation. The NEC requires a disconnect and overcurrent protection on the PV input. Overcurrent protection
can be a fuse or circuit breaker. Thermal circuit breakers require the same 1 .56 times Isc, but MidNite solar
hydraulic/magnetic breakers require only 1 .25 times Isc. All MidNite din rail and panel mount breakers are
hydraulic/magnetic and are rated to hold 1 00% current. The use of a breaker is typical because you also get
the required disconnect at the same time. MidNite Solar manufactures Baby, Big Baby and Quad boxes to
help comply with these requirements.
The wiring diagrams included in these instructions also include another breaker in series with the PV input
breaker. This additional device is a DC-GFP (ground fault protector). The NEC mandates the use of DC-
GFP’s in all residential (NON-MOBILE) solar systems to help eliminate fires caused from faulty wiring. We
find that the best use for these devices is to find wiring errors made during the initial installation. MidNite Solar
manufactures the MNDC-GFP63 that fits in the Baby and Big Baby box along with a MNEPV30 input breaker.
The Big Baby can also hold the battery breaker as discussed above. So one Big Baby box, one MNDC-
GFP63, and two MNEPV30 breakers fit the bill for all NEC required disconnects and overcurrent devices.
Connections to unit should comply with all local codes and ordinances.
Connect battery positive and negative first. Then connect array positive and negative. Then apply power by
turning on the external battery breaker. If the polarity is correct, the unit will power up. If the unit powers up,
and the customer wants to enable the load circuit, they can then install the load fuse. This fuse is supplied
but not installed. The fuse does not need to be installed for the unit to function as a charger. If the battery
cables are to be removed, remove power by turning off the external breaker and remove the fuse. Follow this
procedure each time the battery is connected/disconnected.