Solar charge controller selection help needed

Here is a page from the charge controllers manual, which is what I want to do, save for 2 exceptions:



The inverter battery charger is replaced by the converter and the lights goes to the DC side of my panel. I understand that the inverter in this setup is to DRAW power, not charge the battery.

The controller is rated at 20 AMPS load continuous which is more than I need. We use the LED lights, water pump, and fantastic fans regularly. The furnace is only used once or twice a year but the fantastic fans are obviously off when the heater is used.

Please tell me why this won't work.

Thanks!

Edit: Here is the link to the manual.

Edit 2: Taking this one step further, could I trash the converter completely and uses a high quality 4 stage battery charger when connected to shore power? In a sense, the CC would take over the converters DC duties.

Your solar controller is rated at a maximum 20amps load to a battery. It probably does not provide that current through the "load" terminals. You don't NEED to trash your converter. If it worked to charge your battery, previously, there is no reason to "trash" it.
The best way to connect the output of the solar controller is directly to the battery. If you install a copper bus and connect both the converter and the solar controller to that bus, you can connect the bus to the battery with one set of large cables and have everything working to the max. You can also leave your converter wiring "as is" and connect wires from the controller to the battery.

The connections to your distribution panel are already in place. The distro panel is fed from the battery and also, in a parallel scheme, from the converter. Installing the solar controller is just adding another parallel charging source into the distribution.

None of this has any effect on the monitoring panel. The connection to the monitor is made through RJ45 socket in the controller. You may also have to grab a 12v (+) and install a shunt if that is applicable to the monitor. My guess is that the monitor only measures amps produced by the solar controller and interprets battery voltage into amp hours used or SOC.

You can call me if you wish. I'll send my phone number to you via PM.

Hi,

I personally would not want a "low voltage disconnect". One reason is I use a medium large inverter.

I do not think you understand how to utilize solar too effectively. Solar in most non full time rv's is simply a way to charge the battery bank. 30 amp-hours solar harvest is not adequate to even do that with all but the tiniest of banks.

Here is a simple flow chart.

Budget-->Energy Audit-->Battery bank size-->number of watts-->PWM or MPPT. What ever type of controller is chosen, make sure it has adjustable set points and a temperature probe that is on the battery.

If you use solar as a battery charger, one rule of thumb is between 60 and 150 watts of panels per 100 amp-hours of storage. The smaller the battery bank the higher the wattage needed (per 100 amp-hours). Here is a link to the rather special spreadsheet which includes an energy audit, that N8GS has created to help size solar battery charging systems!
Solar Spread Sheet by N8GS

If you full time or use an inverter lots, then populate the entire unshaded area of the roof with panels. I'm considering replacing my awning with solar panels.

For a nice explanation of solar, try this link:
Golden rules of solar

I have (2) 135 watt Kyocera panels and a Morningstar PM30A controller feeding a Parallex 7155 converter on our fifth wheel.
(4) Grp 24 batteries.
It is a good working system.
I installed the same set up on a comms. trailer I am building.
The only changes are (2) 230 amp 6 volt batteries in series and the newer panels are 140 watts.

skripo wrote:

I got the connection sequence but how can you monitor DC load power consumption if it is not running "through" the controller?
By installing a battery monitor by Victron, Xantrex, Bogart.


As best I can understand now, I connect the the controller as follows:

Battery goes to Controller Battery
Yes.

DC panel goes to Controller Load
No. Connect loads to battery. Don't use Loads terminal and LVD feature

Panels go to Controller in
Yes

And finally, the converter is direct connect to battery.
Yes.

The amperage worry comes in if I need to run 40 AMPS through it.
Sorry. You need 40 A through what?

Here is a PROPER diagram to connect solar system with inverter and loads - it shows 2 controllers, ignore the 2nd one. Page 19.

Thank you all for your help. For reference, the controller I am looking at is the EP Solar Tracer 4215BN (new version) with remote panel and temperature sensor. It is rated at 40 amps battery current and 20 amps load current.

Here is what I understand the consensus to be:

1) I can hook up everything the way I thought in that I can have a parallel charging system. The only contentious portion is using the load terminals to feed the panels.

2) Everybody seems to feel that the load terminals are not designed for high loads, which I understand is the case with some controllers.

I found one person using it the way I want to and he claims that he has no issues. He pointed out that the load terminals on the 4215BN are powered by the panel output and the battery. I don't know if that is a nuance worth mentioning but I assume he felt that this was not the case with other controllers.

I also found this in the manual of the older model:

"Connect load positive (+) and negative (-) to the Tracer load output as shown in figure 3-2. The load terminals may exist voltage, connect carefully to avoid short circuit.

An in-line fuse holder should be wired in series in the load positive (+) or negative (-) wire as shown. Do not insert a fuse at this time. Confirm the connection correct and then turn on the power.

If wiring the load connection to a load distribution panel, each load circuit should be fused separately. The total load draw should not exceed the 20A load rating."

Epsolar (the manufacturer) seems to confirm that I can do exactly what I propose. The new model I am getting boasts improved "diversified load' handling.

Seeing as the 4215BN has protections built in, I will go ahead and use the load terminal to feed the panel and if it does not work, abandon the LDV and get a Vicon.

My final question is what gauge wire do I need for 5' 12 V 20 amp run to the panel and a 2' from the charge controller to the battery?

skripo,

You need to use fuses. #10 wire for the five foot run and #8 for the charge controller to the battery. Larger will result in lower voltage drop.

There is NO advantage to using the load outputs on the charge controller. If you ever exceed 20 amps it will burn out the controller. There is already wire from the battery bank to the DC distribution panel. There is already wire from the 55 amp converter (yes this is RV speak, the really really name is inverter from 120 vac to xx.x volts dc) to the battery bank.

How many watts of panels do you plan on installing?
How many amp-hours is the battery bank?
Are you a weekender or a full time RV person?

Some folks....

You are going to find out that powering the 12V distribution panel from the "Load" terminals is a bad idea. In most controllers, if the battery falls below a certain charge level, the "Load" function is automatically interrupted. In most controllers, a duration cycle is set for the "Load" function. Hopefully, you can set the duration to be constant for your wiring scheme. Hopefully, the controller will output power when there is no sun.
I know what you're trying to accomplish by doing it this way and you're mistaken, IMO. Since you have a communication line open to the mfg, ask them how the monitor operates and if it will tally amp hours used or gained in concert with other devices (converter). Ask them if connecting a device through the "load" terminals increases any functionality or if it affects monitor measurements. You'll know more once you have the bits in hand and more carefully study the situation.

Good luck with your installation.

Do an energy audit. Furnace plus lighting plus water pump may exceed 20 amps if all are going at one time.