Which side of cutoff switch to connect charge controller?

For all the times I have disconnected my controller for service... simply removing the battery cable is fine. I did use a switch to disconnect the panels as that is 100 volts and to be respected.

Byrogie wrote:

Connecting to the converter seems like a waste of distance. It may even confuse the solar when the converter is trying to charge??

Whether it's a waste of distance or not really depends on where the controller, the converter, and the batteries are in relation to each other. On my particular motorhome, it might well end up being a shorter run to the converter than the battery bank directly by a little bit (though it's a hypothetical though experiment at present as I don't have solar installed, nor specific plans for how to set it up).

It doesn't make any real difference in terms of voltages that the controller or converter or battery sees, assuming the wiring is adequate. They're all connected in parallel with each other, possibly with some fuses in between, so they all see the same system voltage (plus or minus the voltage drops due to wiring losses). You aren't going to have 14.4V at the converter and 12.2V at the battery simultaneously, at least in any remotely properly set up system.

That's not to suggest that there's an inherent advantage to tying into the wiring at the converter vs. the batteries--there is none, and indeed in many cases it would be silly to do so.

In either scenario, you have to disconnect the panels before you disconnect the batteries for maintenance. If connected on the load side then you have to disconnect the panels everytime you want to use the battery disconnect. Then you don't get charging.
My controller is connected directly to the batteries. When done camping, I hit the battery disconnect. No parasitic draws and the solar keeps the batteries up. Going to move the connection to the inverter next spring and take advantage of the fat wires.
Connecting to the converter seems like a waste of distance. It may even confuse the solar when the converter is trying to charge??

hedge wrote:

MrWizard wrote:
Sorry but you seemed to have stated that all wrong
If you know the issues of not having the batteries connected
Why would even consider putting it on the load side of the disconnect
When forgetting and using the disconnect would disconnect batteries from controller and damage it ?

Why even consider such a situation

But the issue still exists, I still have to remember to disconnect the panel switch when disconnecting batteries (which in my case is about the only time I turn off the disconnect switch... actually thinking of just removing it)... just a different things to remember.

I've seen installs where they tie in to the converter, they must have this issue.

No real issue.. IF it can't easily and accidentally be disconnected from batteries, the battery disconnect does not disconnect the converter,
It disconnects the house from the batteries, not the converter from the batteries, If you have shore power or generator the amount of solar becomes a moot issue, it adds to system but not as much as when no 120v power is not available, the only issue connecting at the converter is the size of wire and length of run
you are NOT dealing with anything different than all the rest of us with solar
install a DC circuit breaker at the controller between the panel wires and the controller

there are good reasons for connecting the CC directly to the batteries
you go to disconnect the battery cable for any reason,
you see all those those wires, and go "Oh Yeah"
this is Not something you want to make out of sight out of mind
not something and can accidentally be forgotten and pull the switch

Just reading through my Morningstars manual it only mentions that disconnecting the battery while charging could cause a quick voltage spike above 15v that could damage sensitive equipment, no mention of itself being damaged.

This seems like a good reason to keep it I off the load side of the disconnect as well.

MrWizard wrote:
Sorry but you seemed to have stated that all wrong
If you know the issues of not having the batteries connected
Why would even consider putting it on the load side of the disconnect
When forgetting and using the disconnect would disconnect batteries from controller and damage it ?

Why even consider such a situation

But the issue still exists, I still have to remember to disconnect the panel switch when disconnecting batteries (which in my case is about the only time I turn off the disconnect switch... actually thinking of just removing it)... just a different things to remember.

I've seen installs where they tie in to the converter, they must have this issue.

I have mine on the battery side with a breaker between battery and controller for protection and switching. I also have disconnect switch between panels and controller. Only time controller is switched off is if working on batteries.

I see no advantage to having the controller on the load side of the house disconnect with the disadvantage being if someone turns the disconnect (Like when in for service) now solar is not charging.

Sorry but you seemed to have stated that all wrong
If you know the issues of not having the batteries connected
Why would even consider putting it on the load side of the disconnect
When forgetting and using the disconnect would disconnect batteries from controller and damage it ?

Why even consider such a situation

well the thread has taken a left turn as they quite often do around here. I know all about the issues of having the controller without a battery connection and that issue exists and can be managed no matter which side you wire to.

I guess I was trying to get more input on the disadvantages of wiring to the load side other than the ones I thought of myself.

Probably my OCD acting up again but I'm thinking of rewiring and using a Blue sea Safetyhub to consolidate all the fuses into 1 block but it would mean everything would be on the load side of my disconnect switch.

The 12/24 controllers do require the battery connection first so they can decide whether you have a 12 or 24v battery system.

That is different from the issue of maybe frying the controller by not having a battery connection while the panels are connected, which can happen with some. Then there are some (at least one) that says don't have the panels and a load connected with no battery.

Safest thing to do for them all is just never have the panels connected without the battery connected, as recommended by previous posters.