a couple solar charging questions

[RussC]

I'm awaiting a 30W panel and this controller: http://www.amazon.com/gp/product/B002MQW3H8?psc=1&redirect=true&ref_=od_aui_detailpages00
to maintain a single dc 12v cabin battery with light loads. I trailer sail so previously when I get home I have always just plugged in my little C-Tec charger via a permanently installed plug in the transom. what I'm wondering is if I use that charging plug to attach the solar panel, would I still be able to unplug the panel and plug in the C-tec charger to recharge without harming the controller or charger?? the wires from the transom mounted charging plug to the battery are currently #4 except 2" right at the plug, which is #10.
My other question concerns the controller wiring. I notice most controllers have terminals marked "load". are these terminals generally used for all loads, or can loads be attached to the battery posts as they are now?

My first solar setup so thanks for any assist.

Russ

 

[Bill Roosa]

A battery charger is just a 120 volt charge controler. So if you plug in with the solar controler between the panels and the plug you should have no problems.

 

[Brian D]

If you think of the path of the C-Tec charger and the solar charger, you will find that they will both end at the same point; the battery. When on the solar charger, your panels will supply the battery with the voltage and current needed to maintain them. When you get back to the house, you can plug in your C-Tec charger AND still have the solar charger connected. Nothing adverse will happen. So you will be OK either way.

The load is for like lights and such. On a boat, there is no need to have "load" connected to anything. Just connect the panels to the SOLAR input and connect the battery to the BATTERY output. Done.

 

[Benny17441]

Yes, just connect the charger controller directly to the battery and leave the transom plug for connecting the 120V Charger. Both can run simultaneously. I would direct all loads to the battery and use the controller exclusively to charge the battery.

 

[RussC]

Perhaps I worded it poorly. what I was considering was to install the solar controller between the battery end of the existing C-tec charger line and the battery. in other words, if I wanted to un-plug the new solar in order to plug in the C-tec charger I would be going through the newly installed solar controller to charge the battery with the C-tec. I'm hoping to avoid running a separate set of wires for the solar, and using the one plug for both charging methods would be nice also…… if it won't cause problems that is.
I hadn't thought of it previously, but I guess I could install the solar controller under the solar panel. that way it would be out of the system when the C-tec was in use…… I need to check if the solar controller is water resistant I guess. or make an enclosure for it. huummmm.

Thanks,

 

[Brian D]

If I read this right, you want to connect the C-Tec charger to the battery terminals on the solar charger? If that is correct, then WHY? Connecting the charger to the battery and the solar to the battery is fine. Better yet, if you have a battery switch (1-Both-2-Off) then connect both the charger and the solar to the common point on the switch. But I guess if you wanted to connect the C-Tec to the solar charger then go for it. Keep the controller below deck close to the battery. Don't put it outside.

 

[RussC]

Let me try this a whole different way:

LETS JUST SAY: I have a solar system set up on my boat already with a plug on the transom where the solar panel plugs in. this is the waterproof plug just inside the red stripe

the solar controller is on this line in the battery compartment down in the cabin.
I'd like to have a plug on the transom to plug in my C-Tec charger when the boat is in my boat-port at home and the sun has set, so do I need to run another set of wires and mount another plug in the transom just for the C-Tec charger (bypassing the solar controller), or can I just unplug the solar panel and plug the C-Tec into the existing plug to charge my battery?

Thank you

 

[Brian D]

I think I now understand. You want to disconnect the solar panel and then connect the C-Tec to the port that the solar panel was connected?

No. Because you stated that the solar controller was connected to this panel down in the battery compartment. That input to the controller is looking for a specific voltage from the panel (17vdc?) and if it does not see that, it stops the charging process. What is the cutoff voltage? You have to look up that information from the manufacture. Your C-Tec might only produce 13.x volts, maybe 14.x volts. Might not be enough for the solar controller to activate.

 

[RussC]

Yaaaa. I knew there had to be a route around that "failure to communicate" thing. thanks for hangin in there with me

The spec sheet on the controller says: "minimum voltage to operate 6v".

 

[Maine Sail]

You don't want to feed the PV input of a solar controller with a typical battery charger..

 

[centerline]

Russ, it seems you are over thinking a very simple system....
the c-tec charger output cannot be ran thru the solar charger..... it it already putting out the proper voltage, and if you were to attempt to put it thru another "voltage regulator" it will eventually cause damage to one or both of the regulators, and at the very least, be inefficient due to the fact that regulators consume power to do their work.

the solar panel output should be ran thru a solar charge controller, and then directly to the battery.... installed and done!
the shore power charger should be connected directly to the battery.... installed and done!... all that is needed to produce power when the sun goes down, is to plug the c-tec charger into shore power

there is no other correct way to connect multiple charging systems to a battery...
(there may be some variations when you have multiple banks, depending on what type of additional equipment you have in the battery system).

there is no need to disconnect one charger to use the other.... and if you need to install a receptical to bring "shore power" into your boat, and take it forward to your shore power charger, then that is what must be done, as its much better for dependability and long term convenience.
it is plenty easy and cheap enough to run another wire for the shore power connection, and if you use the right size of wire, you wont have to worry about over-amping it when you decide you want to run a space heater in the boat.
...and as long as the solar panel remains connected full time (as it should), it will always take over charging the batteries when the 120v power goes off, for whatever reason....

a safety note... the solar panels do NOT like to be connected/disconnected when they are working (daylight hours), and this could cause damage to them.... it is always best to throw a blanket over the panel to kill the output, when connecting/disconnecting them.

 

[RussC]

I expect your correct centerline. I do tend to over-think many things .

I'll run another parallel line and plug to the battery from the transom. Good to know they can both be attached to the battery at the same time. I had never heard about the potential of harm when disconnecting the panel however. good to know.

thanks.