Charge controller to buss or straight to battery

[docrn]

In the process of installing solar on my boat. Is it acceptable to run the output from the charge controller to the positive buss or does it have to go straight to the battery? I’ve seen both but thought it was always recommended to go straight to the battery.

Thanks

[Warby12]

In my opinion, it's ok to go to the bus if there is very minimal resistance in the cable from the bus to the battery. You need to test the voltage drop while the panels are pushing close to their max current into the batteries to see what that voltage drop is. The test doesn't work if the full current is not flowing because the resistance only shows up under pressure from the full current. There are way smarter people than me on here but I think an acceptable voltage drop would be less than 3%? Otherwise you're just wasting sunlight.


And the fuses need to be configured right

[docrn]

Thanks Warby.

[seandepagnier]

it's better to go straight to battery because if the wire from the battery fails, or the connection is corroded, the solar can put too high of a voltage on the bus and potentially damage some things, don't ask me how i know.

[sailorboy1]

I ran my solar directly to my main DC panel with it's own breaker for years till I wanted to use the breaker location for something else. I worked just fine. As long as your solar can not put out more current than your battery to panel cable capacity and voltage drop you are good to go (with a breaker installed).

[smac999]

If the bus is unswitched. It is the battery.

Only 1 wire should be on the battery. The is the whole point of the bus.

[smac999]

Originally Posted by sailorboy1

I ran my solar directly to my main DC panel with it's own breaker for years till I wanted to use the breaker location for something else. I worked just fine. As long as your solar can not put out more current than your battery to panel cable capacity and voltage drop you are good to go (with a breaker installed).

You can’t run solar to a dc panel because it’’ll shut off with the battery switch. And then try to directly run your loads.

[kencruise]

When connecting batteries: Never cross the remaining open positive and open negative terminals with each other, as this will short circuit the batteries and cause damage or injury. Be sure the batteries you're connecting have the same voltage and capacity rating. Otherwise, you may end up with charging problems, and shortened battery life.

[sailorboy1]

Originally Posted by smac999

You can’t run solar to a dc panel because it’’ll shut off with the battery switch. And then try to directly run your loads.

if only my boat had know for the 4 years it was wired that way that it wasn't working

[NYSail]

Originally Posted by smac999

If the bus is unswitched. It is the battery.

Only 1 wire should be on the battery. The is the whole point of the bus.

I always was told the same and have my connections done that way. Just make sure there is a more than adequate buss bar and cable leading to the battery. And properly fused!

[Sailmonkey]

Originally Posted by kencruise

When connecting batteries: Never cross the remaining open positive and open negative terminals with each other, as this will short circuit the batteries and cause damage or injury. Be sure the batteries you're connecting have the same voltage and capacity rating. Otherwise, you may end up with charging problems, and shortened battery life.

Did you read the original question?

[Stu Jackson]

Originally Posted by smac999

You can’t run solar to a dc panel because it’’ll shut off with the battery switch. And then try to directly run your loads.

Aw, c'mon, smac, you (should) know better.



Assuming a basic 1-2-B switch: Only it if is connected to the C post. If it's on the house battery post, it's just like being connected to the house bank, different end of the same wire.

[tarian]

I wire to the bus bar with adequate fuse just before it clearly the wire from busbar to battery is capable of this common sense I suppose

[roland stockham]

A Buss bar is a solid metal bar with (usually) bolt on terminals next to the battery. Effectively it is part of the batteries terminal post. If you have one then chargers can connect to it. If you have a cable, even a heavy duty one, that connects the battery to a power panel that is NOT a buss bar and chargers should go direct to the batt post.

[docrn]

Thanks for the replies.

I ran it direct to the + post on the battery with gauge 6 wire from a fuse block that is fed by the charge controller. Used a 60 amp fuse about a foot or two away from the battery (I have three 20 amp controllers going to the fuse block). My buss is 150amp but I didn’t think I could do wrong going straight to the battery. My negative goes to the negative buss so as not to bypass the shunt.

Hopefully my boat isn’t on fire right now. Lol.