Looking for advise/help on my system

hackman22

Hi,
New here and new to solar. I have a 12v system with 3 kyocera 315W panels , a midnite classic 200 charger and 10 deep cell 12v / 109ah batteries (walmart) mounted on my RV on the Texas coast.
Now I know 10 batteries in parallel is not recommended but that's what I have. I wired them diagonally.

I had the panels flat on the roof and had about 110V 650W bulk charging at 14.8V amps around 45.
I angled them toward the sun and my voltage increased to 130+ but my watts dropped to 250 and Amps to 30.
Is voltage better then watts? or should I maybe lower the panel angles until I get the watts back up?
(no shadows on panels)

Next my charge controller quits bulk and goes to absorb and float but doesn't seem to want to go back to bulk.Shouldn't it do that if I'm burning energy?
It goes thru all phases and by 7pm it rests but end voltage at that point is 12.6 to 12.4
Lastly,
battery array...
Any Ideas on how I can make it work better (especially if that's why I'm not getting a full charge)
I have them connected with 4 & 6 gauge (lawn & garden with the preattached ends) wires around 24"....same lengths to next battery but varying length/gauges from one to another so it's a bit of a mess. I understand your suppose to use same size/length cables but is this minor or a major problem?
I also have a ton of stuff all connected to the first battery....controller,1500w inverter,many "who knows what" wires from the rv. Is there some kind of bar I could hook everything to & maybe all the negative cable/positive cables or??????

Sorry if I sound like an idiot...I'm just learning all this stuff!
Oh yeah and my 5000w genset generator stopped charging the batteries. No more red light at all yet all dc and ac works.Maybe I blew it with the inverter being on? Having a hard time tracing wires to battery. Been using a little 10amp charger plugged into ac when gen is running.
I'll get a lot more info on all this if the sun ever comes back out.
Thanks in advance for any help
Rob H.

Cariboocoot

Re: Looking for advise/help on my system

Welcome to the forum.

First a bit of reassurance: your charge controller is functioning normally. It will go from Bulk to Absorb to Float, but will not go back to Bulk unless the Voltage drops below the rebulk set point. As long as the Voltage stay above that it won't go to Bulk until the next day. If it is doing that you haven't got a problem. You can check the manual for what the rebulk setting is and how to change it, but if you've still got 12.6 Volts showing at night that is not a worry.

As you know your battery set up is a mess. You really can't wire ten parallel sets 'diagonally' as there will be a difference in the wire lengths to each one. The only possible way to connect that many is with bus bars. Even that is likely to be unsuccessful with that many.

Here's a worse thing: ten times 109 Amp hours is 1090 Amp hours. That should have about 1600 Watts of panel to recharge it. You have 945, which could put out about 60 Amps and handle 600 Amp hours @ 12 Volts. You would probably improve performance by checking all your batteries and eliminating about half of them. No kidding. Do you really need 6kW hours of stored power? I have less than half that to run the whole cabin.

Panels. The power going in to the charge controller isn't what matters so much as the power coming out. Both are dependent on insolation and the SOC of the batteries. Both of those factors vary from moment to moment. 14.8 V @ 45 A is 666 Watts. You would likely see no more than 727 from your panels, as the typical average output of panels + controller tends to be 77% of nameplate rating. If the batteries don't need more than 45 Amps, they won't draw it.

You have to beware of RV wiring. They tend to have generators and 'converters' used to power the DC stuff when the gen is running or shore power is attached. When you add an inverter, it is all to easy to get the wiring confused. A typical problem is the converter being powered off the inverter and then trying to charge the batteries that are running the inverter! It goes 'round and 'round and uses up power without accomplishing anything. It is best to get an inverter/charger and toss the converter in the trash.

Any help?

hackman22

Re: Looking for advise/help on my system

So the reason I'm not getting a full charge is because I have too many batteries?
When I got my system I was saying I wanted 2000aH and she said 10 batteries would be about right...
I tried to run a chest freezer which says it's 3A/110V but I had to unplug it before midnight as my controller read 12.2V. It was 11.9 the first morning after running the freezer then I started watching it closer. I'm giving up on the freezer at least for now.
If I run a 23" lcd tv a box fan a 415w inverter and an antenna amplifier as my only loads from the time the controller rests (at say 12.5) by midnight it's down to 12.3V ... does that sound right?
I have shore power plugged into the inverter which is hooked to the batteries so the converter isn't charging at that point. When/if I get to 12.2v I power that off and just use 2 415w inverters.
Just seems like I'm not getting a whole lot of power

CATraveler

Re: Looking for advise/help on my system

I agree that the batteries are a mess. Also your post implies that you have marine deep cycle batteries which ARE NOT deep cycle batteries.

I'd suggest that you learn from your present setup and when you do replace the batteries get true deep cycle batteries and get larger sized batteries perhaps 6V. 4 6V GC batteries would give you 460AH or use a bigger battery if you need more power. Also 4ga wires are likely to small.

Also it's best to wire the batteries in a balanced setup which is difficult with a large number of batteries.

CATraveler

Re: Looking for advise/help on my system

You need a better estimate of your usage to help decide on panel and battery sizing. The Kill A Watt meter can help. You might want to consider a battery monitor.

"I have shore power plugged into the inverter which is hooked to the batteries so the converter isn't charging at that point. When/if I get to 12.2v I power that off and just use 2 415w inverters."

When on shore power you don't need the inverter and the converter should be charging the batteries. With no shore power then the inverter supplies 120V. An inverter doesn't have 120V input unless it has a built in transfer switch so that it's AC output is supplied from shore power or the inverter itself.

Cariboocoot

Re: Looking for advise/help on my system

hackman22 wrote: »

So the reason I'm not getting a full charge is because I have too many batteries?
When I got my system I was saying I wanted 2000aH and she said 10 batteries would be about right...
I tried to run a chest freezer which says it's 3A/110V but I had to unplug it before midnight as my controller read 12.2V. It was 11.9 the first morning after running the freezer then I started watching it closer. I'm giving up on the freezer at least for now.
If I run a 23" lcd tv a box fan a 415w inverter and an antenna amplifier as my only loads from the time the controller rests (at say 12.5) by midnight it's down to 12.3V ... does that sound right?
I have shore power plugged into the inverter which is hooked to the batteries so the converter isn't charging at that point. When/if I get to 12.2v I power that off and just use 2 415w inverters.
Just seems like I'm not getting a whole lot of power

Well whoever picked your batteries wasn't very good at math. :roll:
A freezer will have two aspect of power usage: its total Watt hours per day and its start surge demand. Usually 1kW to 2kW inverter will handle the start, especially if it is true sine wave. The other is likely to be in the neighbourhood of 1kW hour to 2kW hours per day. On a 12 Volt system that shouldn't be more than 200 Amp hours tops. You should get a Kill-A-Watt meter (about $30) and test that freezer to see how much power it does use in a day. I've tested many and can say they are all over the range and some are really horrible power users.

You can use the Kill-A-Watt to measure any other 120 VAC things you use, and then you'll have a realistic idea of how many Watt hours you need to supply each day. Your 945 Watts of panels should be capable of just under 2kW hours of AC per day. I'd plan around that, which would be the 600 Amp hours of battery I mentioned before at 25% DOD.

Your wiring mess, btw, may also be responsible for early low Voltage and problems running heavier loads like the freezer. It's amazing how much Voltage drop there is on undersized wires in a 12 Volt system. For a 1500 Watt inverter all the battery cables ought to be '0' gauge or larger as it will draw up to 125 Amps at full power. 4 AWG is only good for about 95 and 6 AWG about 60.

CATraveler

Re: Looking for advise/help on my system

A 3A freezer will draw about 33A DC using an inverter. With a 30% duty cycle that would be: 33*.3*24=238AH per day. That is a lot for a RV but gives you an idea of how to calculate loads. Or the Kill A Watt will just measure the actual usage.

icarus

Re: Looking for advise/help on my system

You should also realize that using battery voltage solely as a way of determining State of Charge (SoC) is very inaccurate, especially if batteries are being either charged or discharged. To test voltage, batteries should be at rest for several hours, and with a Bank your size, I do men several! Then, and only then can yet a somewhat meaningful SoC from voltage. A battery under load might drop as low as. 10 vdc, even though it is fully charged. On charge, it might show 14.6 vdc.

The very first thing I would do is red, and understand, the following.

http://www.batteryfaq.org/

http://www.windsun.com/Batteries/Battery_FAQ.htm#Lifespan%20of%20Batteries

Good luck, welcome to the forum, and keep in touch,

Tony

hackman22

Re: Looking for advise/help on my system

Sorry, I misspoke on the shore power.What I meant was my RV AC cord is plugged into the inverter (which is hooked to battery) which powers up all the AC outlets.

So how about I go to 6 batteries in parallel with 0 gauge equal lengths to connect them together. You think that will cure my problems? I don't use very much power at all. If I can get it charging properly I can then see about running the freezer or other heavy loads. My fridge runs on propane as well as cooking,heat.
Is there something I should connect the batteries & controller to (other the the 80a buss mrcb) or should I just connect all the loads to the first battery?


catraveler-Deep cycle batteries aren't deep cycle batteries? Do you mean they are just crappy deep cycle batteries??

(8PM already at 12.2V)

CATraveler

Re: Looking for advise/help on my system

A marine deep cycle battery is a compromise that is closer to a starting battery than a deep cycle battery like a Golf Cart battery (GC). A marine battery does well as a compromise and for trolling motors etc. A deep cycle battery has a different design inclucing heaver plates etc. They are designed for deeper depth of discharge and longer life.

In my last MH I had 4 Interstate GC's for 460AH capacity.

I think someone posted some links on batteries?

Cariboocoot

Re: Looking for advise/help on my system

Despite manufacturers' claims, the "RV/Marine deep cycle" batteries aren't really suitable for RE use. The usual problem is that they don't last very long.

Get a hydrometer from an automotive store. Charge the batteries from a standard 12 V charger individually (this will take days). Let them rest for at least 3 hours. Check the specific gravity of each cell with the hydrometer (please don't tell me these things are sealed!). Find your five best batteries (highest SG readings) and put them together with the thickest wire you've got. See if there's any improvement. It may already be too late.

There is no sense in buying thicker wire now because you are going to want to change those batteries out to something like GC2's or L16's of a real deep cycle design. These will be 225 or 320 Amp hours @ 6 Volt and will be much more suited to the usage. Most of your problem is likely in the wiring. The only way to really solve that is to change the batteries.

CATraveler

Re: Looking for advise/help on my system

Balanced battery wiring
http://www.smartgauge.co.uk/batt_con.html

hackman22

Re: Looking for advise/help on my system

I've read that one too. I'm using method 2

Cariboocoot

Re: Looking for advise/help on my system

hackman22 wrote: »

I've read that one too. I'm using method 2

That really only works best with two batteries. For more than that you need to use either method #3 or #4.
Having more than two parallel strings tends to have problems no matter how well wired they are.

A somewhat related thread: http://forum.solar-electric.com/showthread.php?15989-Battery-System-Voltages-and-equivalent-power

hackman22

Re: Looking for advise/help on my system

They aren't sealed. I'll see how many I can return to walmart. I bought half in July , 4 in AUGUSt and one last week. I'll go with what I can't return. I did get a hydrometer the other day so I could test them. What size wire will I use with some trojan 6V's?

I wish AW&S would have gave me an idea on what I needed in the first place and some (at least basic) instructions with my system would have been nice.

Cariboocoot

Re: Looking for advise/help on my system

The wire size on the big 6 Volt batteries would be the same as I mentioned before: minimum '0' gauge. It is based on the amount of current expected to be drawn which is a function of the Watts @ Volts.

I can't speak to whatever lack of info you got from whomever sold you the equipment. Sometimes if you don't ask the right questions they just assume you know what you're doing and what you want. This stuff is by no means simple. 8)

BB.

Re: Looking for advise/help on my system

hackman22 wrote: »

Sorry, I misspoke on the shore power.What I meant was my RV AC cord is plugged into the inverter (which is hooked to battery) which powers up all the AC outlets.

Just to be really clear--On many RVs--The RV AC cord is the shore power connection which powers all the AC outlets, including the AC to DC converter (essentially an AC to DC battery charger).

And, if the converter is active--Then the inverter can actually be powering the battery charger/converter which is charging the battery bank, which is powering the AC inverter, which is powering the battery charger/converter...

Obviously--that is just wasting power. So--double check that the Converter is not powered when you are running your AC inverter and the AC outlets in your RV.

-Bill

hackman22

Re: Looking for advise/help on my system

I think I may have blown the converter/charger the first time I plugged it into the inverter. I will check it though.
I never really got a clear answer on the volts/watts issue on my panels. Tilted I get higher volts but less watts,flat I get more watts and less volts....which is better?
Also I'm going to scrap my battery bank and am going to get Trojan 6V batteries. How many and which model do you guys recommend?
I don't want to make any more mistakes. lol

Cariboocoot

Re: Looking for advise/help on my system

hackman22 wrote: »

I think I may have blown the converter/charger the first time I plugged it into the inverter. I will check it though.
I never really got a clear answer on the volts/watts issue on my panels. Tilted I get higher volts but less watts,flat I get more watts and less volts....which is better?
Also I'm going to scrap my battery bank and am going to get Trojan 6V batteries. How many and which model do you guys recommend?
I don't want to make any more mistakes. lol

Power is Watts. As far as the input to an MPPT type charge controller is concerned, V * I = W no matter what the V or I. In the case of a PWM controller you are looking for maximum I, because the 'extra' V isn't going to figure into the W: their output power is a function of I * battery V For feeding an MPPT controller you want to keep the array Vmp as close to battery Voltage * 2 as possible. I believe your panels are all in series, so that is out. Why they are all in series is another matter: you shouldn't have any problem with long wire runs needing high array Voltage to overcome V-drop, so running an array with 100+ Volts on a 12 Volt system will mainly result in your controller running less efficiently.

Your KD315 panels have a Vmp of 39.8. You should rewire them in parallel to the charge controller. You will need to put a fuse or breaker on each one (10 Amp). This will improve the controller's efficiency and reduce adverse effects of shading on any one panel or imperfect insolation.

RV's have a problem with panel aiming because they aren't always parked in the same spot so you can't always get that best insolation. There are two angles that matter, so whereas tilting them up might seem to improve the angle one way it may actually turn the panel away from the sun the other. This is why RV installs usually leave them flat and take their chances. As long as you don't go camping in the Cariboo in Winter it will work.

When you get your actual power consumption determined you can pick batteries. Based on what I've seen so far you are looking at something like these 305 Amp hour Crown L16's: http://www.solar-electric.com/cr305am6vode.html

CATraveler

Re: Looking for advise/help on my system

Cariboocoot wrote: »

Your KD315 panels have a Vmp of 39.8. You should rewire them in parallel to the charge controller. You will need to put a fuse or breaker on each one (10 Amp). This will improve the controller's efficiency and reduce adverse effects of shading on any one panel or imperfect insolation.[/url]

I keep thinking that serial has the advantage of partial shading on a diode bypass portion of a panel given that it's a RV that may be parked whereever. The MS MPPT 60 manual has a graph showing the efficiency tradeoff for higher voltage.

Further thoughts on serial vs parallel?

Cariboocoot wrote: »

When you get your actual power consumption determined you can pick batteries. Based on what I've seen so far you are looking at something like these 305 Amp hour Crown L16's: http://www.solar-electric.com/cr305am6vode.html

Nice battery and I would only add the typically RV's have space limitations including height that have to be considered.

Cariboocoot

Re: Looking for advise/help on my system

"Shading" is a highly subjective term. Partial shading of a single panel, partial shading of the whole array, total shading of a single panel. The term "partial" may indicate reducing output by blocking insolation from one string within a panel or array. How a shadow falls on a panel and how that particular panel is connected internally will have an effect on the result. Thus partial shading results aren't really quantifiable.

What we're looking at here is losing all or some of the power from one panel and the difference that will have on output between serial and parallel connections of those panels. In the case of serial connecting dropping one panel's power output causes the power from the others to flow through its bypass diodes. This can be an increase in resistance resulting in a current limitation (like putting an 8 Amp panel in series with a 4 Amp panel; the current is limited to the lower amount). Over long term this could damage the shaded panel as the bypass diodes aren't meant for constant or continual use as a current path (they don't have heat sinks for one thing). In a parallel configuration one panel's output dropping merely reduces its contribution to the total; the other panels are not affected. This is the reasoning behind my preference for parallel connections in such an application. That and the greater efficiency of the controller.

But just my opinion. Everyone is free to do as they like in that regard.

hackman22

Re: Looking for advise/help on my system

The RV is staying where it is parked permanently unless a hurricane comes. I built a roof over the entire top of the 31' RV so there is absolutely nothing to shade any part of any panel.
I return 6 batteries to wallyworld today and got a full refund on them. I'm going to use the four left for now,see how that goes and go from there. I'm running them in parallel with equal length 4 gauge (lawn & garden) pre-made cables.
I see what the moderator said earlier....you can't determine the battery voltage at the controller.
It said 12.2. I checked the batteries hooked up still and I got 12.35. I disconnected the last one and it steadily increased to 12.5 in about 15 minutes.
Guess I need a battery monitor a charger/converter and eventually better batteries.
Thanks for all the help....Now if I only had a wiring diagram for a 1983 pace arrow I could figure out the generator/converter/battery wiring.The ran a ton of stuff in there!