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?
Quote from: Zakarume on October 31, 2014, 04:48:02 AM
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
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
Quote from: Zakarume on October 31, 2014, 05:45:40 AM
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
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
Quote from: Zakarume on October 31, 2014, 05:45:40 AM
Now as far as distance goes
Panels to Combiner box is about 35 ft.
Combiner Box to charge controller is about 10 ft
Quote from: Zakarume on October 31, 2014, 07:40:53 AM
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
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
Quote from: Zakarume on October 31, 2014, 10:34:08 AM
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
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
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
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
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.
Quote from: Zakarume on October 31, 2014, 04:48:02 AM
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.
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
Quote from: New KID On The Block on October 31, 2014, 04:35:54 PM
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
Ok so lets all start over. I think going 12v was a mistake. I am now wanting to go 24v
Here is my idea so far
1. 4 x 100w Renogy panels. Will go series x2 for 2+ and 2- to Combiner box OR
Connect 2 panels together in series plus other in series and then adding MC4 Branch Connectors and run 1+ and 1- to Combiner box. Want to stay with combiner box for upgrades in future
2. Get the Midnite Kid Charge Controller
3. Need to get a 24v inverter. Need a good recommenation and cheap
4. Wire would be http://www.amazon.com/TEMCo-Extension-Connector-LIFETIME-Warranty/dp/B00LOM7K2Y/ref=sr_1_6?ie=UTF8&qid=1414801691&sr=8-6&keywords=solar+power+cable+100ft+10+awg
Like i said. New to solar and this is a DIY Project with limited funds.
Quote from: Zakarume on October 31, 2014, 08:24:50 PM
Ok so lets all start over. I think going 12v was a mistake. I am now wanting to go 24v
Here is my idea so far <snip>
Each string (of two panels in series) will have its own 10 gauge cable running 35 ft to the combiner. That will give you a 1.15% voltage drop. Very reasonable. If you combine more than two strings, you will need something heavier than 10 gauge cable.
Quote from: Zakarume on October 31, 2014, 08:24:50 PM
Need to get a 24v inverter. Need a good recommenation and cheap
That's not the way it works... you actually get more value when you spend a bit more.
To advise you any further, about inverters, combiners, cable, or anything else really, It would be helpful to know what sort of installation this will be... is this for a boat? a house? Are you required to conform to a building code? Do you want to conform to code? What sort of loads will you put on the system? It's hard to recommend an inverter without knowing what it will be powering.
--vtMaps
Quote from: Zakarume on October 31, 2014, 08:24:50 PM
Ok so lets all start over. I think going 12v was a mistake. I am now wanting to go 24v
One more thing I forgot to mention... with a 24 volt system, I would consider that three of your panels would be the optimum string length.... two more panels would give you a total of 6 panels... two strings, each string being three panels in series.
Mr reasoning is that two panels in series has the bare minimum of headroom on a 24 volt system. Especially if your panels are hot and your batteries are (relatively) cool.
Of course, I know so little about your system... it is hard to know whether you would be better of with a string length of two or three. Are there any shading issues? If so, that might argue for three strings of two panels per string. What sort of climate? That also might influence my recommendation.
--vtMaps
All it will be powering is a computer, monitor, small speakers, fan and light occasionally. Recharging cell phone and car alarm. And not powering those i will power a TV. Will be using around 250 watts. 100 watts for TV. I only have 4 panels, but upgrade in future. I rather keep it 2 panels in a string
People come here for advice then ignore it. 2 36 cell panels on a mppt controller running 24V doesnt give the controller enough headroom. If you want to do that get a PWM controller which will work fine like that,
I will be using my Renogy PWM Charge Controller for now. When i upgrade more panels into system i would like to go with the Midnite Kid Controller. But for now i will be using the Renogy
To answer your question about good quality but less costly inverters look at Samlex sine wave inverters. Larger more costly inverters usually are capable of charging batteries from a generator . If you don't need that look at the Samlex.