A Forum run by Enthusiasts of MidNite Solar

Charge Controllers and Clippers => The "KID" charge controller => Topic started by: Biopwr on July 22, 2014, 07:24:37 PM

Title: Help With New Setup on RV Application
Post by: Biopwr on July 22, 2014, 07:24:37 PM
I have a Kid connected to the following:
FW 1742
I have a 270 watt 24 volt panel on my RV
Voltage Max Power - 31.5
Current Max Power - 8.58
Voltage open Circuit - 38.5
Current Short Circuit - 9.17

I have 4ea, 6 volt Energizer Batteries wet cell, 440 AMP HR and they are connected to my 100 watt Xantrax Pure sign inverter.
The panel is 25 feet from my Kid and I used 10 AWG solar wire ran threw the Big Baby Breaker Box and then 10 AWG wire 15 feet to my batteries.
My Batteries are wired with 2/0 cables and 2/0 cables to my inverter 4 feet.

When in use I use my battery power down to 12.2 and the next day in full sun I have trouble getting enough power to totally recharge my batteries to anything over 12.6.

After this last trip when I returned home my batteries were at 12.2 and it has taken 2 days with all power shut off to recover to 13.4.

I have left it in Factory setup and I am on FW update 1742

Can someone commend any changes that I could make to recover any faster. ???
Title: Re: Help With New Setup on RV Application
Post by: dgd on July 22, 2014, 07:46:29 PM
The one 270 watt panel is probably not providing enough  power to fully charge the batteries. Recommend installing, at least, a second identical panel
dgd
Title: Re: Help With New Setup on RV Application
Post by: Biopwr on July 22, 2014, 08:24:04 PM
I thought about that but I never get more than 180 watts out of the 270 watt panel that I have so that is why I thought it might be in the setup. Do you suggest that I leave all the settings on factory then and just add another panel to boost the input up.
Title: Re: Help With New Setup on RV Application
Post by: vtmaps on July 22, 2014, 08:41:58 PM
Quote from: Biopwr on July 22, 2014, 08:24:04 PM
I thought about that but I never get more than 180 watts out of the 270 watt panel that I have so that is why I thought it might be in the setup. Do you suggest that I leave all the settings on factory then and just add another panel to boost the input up.
Welcome to the Midnite forum,

180 watts from a 270 watt panel isn't too bad.... We usually derate solar arrays by about 25% to account for the fact that hot panels in the sun do not produce their specified output, other losses in wiring, controller, dirt on panels, less than optimum tilt of panels (are they flat on your RV?), etc.

Even if you did get a full 270 watts, I don't think you have enough panel to charge those batteries.  We usually recommend (rule of thumb) to have a 10% charge rate.  With 440 ah of battery it would be good if you could get your charge rate up to 44 amps.  44 amps X 12 volts = 528 watts of panel.  Since you want to derate the panels (as mentioned above), 528 watts ÷ .75 = 704 watts of panel.  That's more than the Kid can handle (in optimum conditions), but optimum conditions are not frequent. 

It may not be practical to put that much panel on an RV... in which case you will need a generator (or shore power) and a battery charger to rescue your batteries.  This is critical or you will ruin them (if you haven't already ruined them).  Get an hydrometer and find out where you stand.

As far as changing the settings on the Kid... I doubt it will help... first you need to supply the Kid with enough power to do its job.

--vtMaps
Title: Re: Help With New Setup on RV Application
Post by: Free Energy Freak on July 22, 2014, 08:45:37 PM
Plugging in the variables you posted to the Kid Sizing Tool (http://www.midnitesolar.com/sizingTool_kid/index.php), and leaving all others at default settings, I get 9.4 amperes charge rate at your batteries. You have a 24vdc @ 440AH. That is well under what the bank needs in order to recharge fully during the day.

Thou needest more panels. :)

EDIT: I see vtMaps beat me to it. What about going with a lower AH rated bank as an option?

Title: Re: Help With New Setup on RV Application
Post by: Biopwr on July 22, 2014, 09:18:42 PM
I havens dropped my usage below 11.9 yet so do you think that I should try and run on just 220 ah (1 set of 6 volt) until I can get the other panel installed, I have room to put up 2 more panels but then I will be over the max charge rate for the kid so would I change to the classic when I get all three up. ( or should I just plan on adding another Kid with 3 panels.

I want to do it right but need to do it in phases so I can keep the cost down.
Title: Re: Help With New Setup on RV Application
Post by: Free Energy Freak on July 22, 2014, 09:32:01 PM
Quote from: Biopwr on July 22, 2014, 09:18:42 PM
I havens dropped my usage below 11.9 yet so do you think that I should try and run on just 220 ah (1 set of 6 volt) until I can get the other panel installed, I have room to put up 2 more panels but then I will be over the max charge rate for the kid so would I change to the classic when I get all three up. ( or should I just plan on adding another Kid with 3 panels.

Running a 12vdc bank and the single panel will improve your charge rate, considerably. Plug your variables into the Sizing Tool and you will be able to sort the best for your situation. http://www.midnitesolar.com/sizingTool_kid/

I guess it all boils down to how much space you have on your roof for panels. 
Title: Re: Help With New Setup on RV Application
Post by: vtmaps on July 22, 2014, 11:07:47 PM
Quote from: Biopwr on July 22, 2014, 09:18:42 PM
I havens dropped my usage below 11.9 yet
<snip>
I want to do it right but need to do it in phases so I can keep the cost down.

You want to keep your cost down?  Your cost will skyrocket when you ruin your batteries (if you haven't already ruined them).  They get stratified and sulfated if they are not brought up to 100% charge at least once a week.  You cannot judge their SOC (state of charge) by voltage... you need to spend $15 and buy an hydrometer.  This is urgent. 

You also need to buy or borrow a battery charger ASAP and get those batteries charged all the way.

--vtMaps
Title: Re: Help With New Setup on RV Application
Post by: Westbranch on July 23, 2014, 12:43:15 AM
No need  as MN's HalfCrazy said in another thread, on overpowering the KID, it will just limit you to 30 amps output... but I personally would not run my equipment at the upper limit, too much heat and wear and tear...