Midnite Kid and New to Forum

[Zakarume]

Hello. I am new to this forum and have a question about the Midnite Kid. I have 4 x 100 Watt Renogy Panels. Spec are


Renogy 100W Monocrystalline Bendable Solar Panel
Maximum Power: 100W
Maximum System Voltage: 600V DC (UL)
Optimum Operating Voltage (Vmp): 17.7V
Open-Circuit Voltage (Voc): 21.7V
Optimum Operating Current (Imp): 5.70A
Short-Circuit Current (Isc): 6.10A
Maximum Series Fuse Rating: 15A

From what i have read about the Midnite Kid and theses panels then the Kid could support a total of 600 watts as long as i don't go over the 150 vdc input. Will this work?

[vtmaps]

Hello. I am new to this forum and have a question about the Midnite Kid. I have 4 x 100 Watt Renogy Panels.
<snip>
From what i have read about the Midnite Kid and theses panels then the Kid could support a total of 600 watts as long as i don't go over the 150 vdc input. Will this work?

Welcome to the forum,

The Kid is rated to push 30 amps into a battery, regardless of the battery voltage. (which you did not specify.  I will assume 12 volts).

Of course, 'amps' is current, not power.  To get the power, multiply the 30 amps by battery voltage. 
-----------Example: 
Let's say it's cloudy in the morning and by noon your battery voltage is down to 12.2 volts.
All of a sudden the sun comes out and Kid is pushing the full 30 amps into the battery.
30 amps X 12.2 volts = 366 watts.  Therefore, 366 watts is the Kid's limit.

Later, you reach your absorb voltage of 14.4 volts
30 amps X 14.4 volts = 432 watts.  Therefore, 432 watts is the Kid's limit.
--------End example

You can see that with a 24 or 48 volt battery, the power handling capacity of the Kid is 2 or 4 times higher.

You mentioned the Kid could support 600 watts... That would be 600 watts of Panels.  Solar panels seldom achieve their STC ratings, and there are losses in the wiring to the Kid, and in the Kid itself... therefore it is necessary to 'over panel' the Kid if you really want it to work at the max. 

From time to time your panels may actually put out their rated power (Vermont winters are cold enough that the panels can operate at STC).  If the output exceeds the Kid's power rating it will clip the excess power.

Personally, I don't think it's good conservative design to continuously max out any power electronics, including the Kid.

Now, back to your 4 panels... it sounds like you are planning to wire them all in series.  If that is your intention, you should know that is NOT an optimal configuration for the Kid.  If the distance from the panels to the Kid is very great, then it MAY make sense to wire them all in series, but you should understand the compromise you are making. 

--vtMaps

[Zakarume]

Sorry it is a 12v system. Only using it for backup power and running computer couple hours a day. I want to replace the PWM Charge Controller with the Kid and possibly the Classic 150 if i get more money to get Classic. Ok so 600 watts is not good. Would 500 watts be OK? I am just looking down the road of upgrading if i decide to that. 

Now as far as distance goes
Panels to Combiner box is about 35 ft.
Combiner Box to charge controller is about 10 ft

[vtmaps]

Now as far as distance goes
Panels to Combiner box is about 35 ft.
Combiner Box to charge controller is about 10 ft

How do you intend to configure your 4 panels?  (series, parallel, series-parallel)   --vtMaps

[Zakarume]

They will be ran to a combiner box. 4+ and 4- cables will be ran to box total of 8 cables. Then 1+ and 1- to Charge Controller. There is so much i have been reading on solar power. I am now starting to look at 24v systems. Even if i go that route, still need the controller and new inverter as mine is a 12v

[vtmaps]

Now as far as distance goes
Panels to Combiner box is about 35 ft.
Combiner Box to charge controller is about 10 ft

They will be ran to a combiner box. 4+ and 4- cables will be ran to box total of 8 cables. Then 1+ and 1- to Charge Controller.

That means you are running them all in parallel.  You have to be very careful of voltage drop.  Why do you have the combiner 35 ft from the panels?  It is more typical (but certainly not required) to have the combiner close to the panels.  You will probably need 'extension cords' to get from the panels to the combiner.  Also, the type of wire you use between the panels and the combiner may have to be very expensive PV wire (unless you are running conduit from the panels to the combiner).

What size and type of wires are you planning to use between the panels and the combiner?

You might be better off in several ways if you wire your panels as series/parallel... that is, two panels in series to make a string and then use the combiner to combine the two strings for the final run to the controller.

--vtMaps

[Zakarume]

Due to situation on my place i had no other choose but to put panels about 45ft from Charge Controller. I am putting in a combiner box 35 ft from panels and 10 ft from charge controller. Wire size wire i will be using is 8 awg. I will be buying my own wire and putting the MC4 Connectors on them,

http://www.homedepot.com/p/Southwire-500-ft-8-Stranded-THHN-Black-Cable-20488312/202316337#product_description

[vtmaps]

Wire size wire i will be using is 8 awg. I will be buying my own wire and putting the MC4 Connectors on them,

http://www.homedepot.com/p/Southwire-500-ft-8-Stranded-THHN-Black-Cable-20488312/202316337#product_description

That wire is NOT suitable for outdoor exposure.  It must be entirely within conduit.  Do your panels have wires attached to them, or do they have junction boxes with no wires coming out of the junction box?

--vtMaps

[Zakarume]

The wire in the description says it can be used indoor/outdoor. Plus another solar company uses it http://www.civicsolar.com/product/8-awg-thhn-stranded-black-cable-500ft-spool

Yes i have wires attached to panels

http://www.renogy-store.com/100watts-bendable-panel-p/rng-100db.htm   And i am not using metal frame panels

[TomW]

Zakarume;

vtMaps is right. That cable is NOT exterior rated so will need to be in conduit if it is outside..

Sad but true.

Tom

[Halfcrazy]

That wire in the link is basic THHN it will last about 2 years Max outdoors and the insulation will crack and fall off. You need that wire in conduit or use a wire rated for exposure.

Ryan

[Mtn Don]

zakarume, possibly you misinterpreted the wire description.  It states "For use in wet or dry locations ". That is true. But note it also states, "mainly intended for use in conduit". Part of that reason is that the insulation outer covering is not UV resistant. Exposed to UV the (usually) clear outer jacket will degrade and breakup.  The wire is rated for wet locations as inside conduit is classified as a (potentially) wet location.

[New KID On The Block]

Hello. I am new to this forum and have a question about the Midnite Kid. I have 4 x 100 Watt Renogy Panels. Spec are


Renogy 100W Monocrystalline Bendable Solar Panel
Maximum Power: 100W
Maximum System Voltage: 600V DC (UL)
Optimum Operating Voltage (Vmp): 17.7V
Open-Circuit Voltage (Voc): 21.7V
Optimum Operating Current (Imp): 5.70A
Short-Circuit Current (Isc): 6.10A
Maximum Series Fuse Rating: 15A

From what i have read about the Midnite Kid and theses panels then the Kid could support a total of 600 watts as long as i don't go over the 150 vdc input. Will this work?

I have the same setup. 4 x 100w Renogy mono panels. (2) more are coming tomorrow, so I'll then have a total of 6 x 100 mono panels. I'll either link all 6 in series or I'll series/parallel link them. I will try out 6 of them in series first as that's the easiest way to connect them. If I'm loosing too much in the down conversion, then I'll try series/parallel connecting them.

I have my system set up as a 24v system with a 24v inverter.

[Zakarume]

Ok so i still have a issue on wire. I can not move my panels where they are at (4x100 watt panels) so would it be best to with a couple http://www.amazon.com/Renogy-Branch-Connectors-Solar-connector/dp/B00BCWRB48 and then http://www.amazon.com/Solar-Panel-Cable-Extension--Resistant/dp/B00IEK6MKA/ref=sr_1_3?ie=UTF8&qid=1414789938&sr=8-3&keywords=50+ft+solar+cable to the combiner box. and if this is possible how much is loss on power. This is just an examble.  If anyone has a better way and cheaper. link me step by step on how to do this

[dgd]

I have the same setup. 4 x 100w Renogy mono panels. (2) more are coming tomorrow, so I'll then have a total of 6 x 100 mono panels. I'll either link all 6 in series or I'll series/parallel link them. I will try out 6 of them in series first as that's the easiest way to connect them. If I'm loosing too much in the down conversion, then I'll try series/parallel connecting them.

I have my system set up as a 24v system with a 24v inverter.

Should be ok with 6 in series  . Better low light performance with negligible loss compared to two by 3 in series.
You could also use 8 of these panels via KID with 24volt battery although 2 strings of 4 in series would be the best PV configuration

Dgd