Kill switch doesn't turn off all power

[Bribenn]

Hi,

I recently set up a solar system in my van and it is all working well except for one small (potentially huge) thing. I have a kill switch wired directly off of the battery with the intention to be able to quickly shut off power should anything go wrong. When I turn it to the off position though, my lights and fan still run for a couple of minutes, as if there is power just chilling in the system somewhere. Is this normal? Is it ok? Is there anything I should/can do about it? I'd be really grateful for any advice. :D

My setup is a modified version of Will Prowse's 400w system with alternator charging. I've attached a drawing of what's connected.

 

[snoobler]

Why do you have a second (-) to the same bus bar as your shunt? You're effectively bypassing the shunt.

What is the DC-DC charge controller?

 

[Bribenn]

I don't actually know why I have a 2nd negative. I probably didn't think about it just going through the shunt. The shunt seems to be giving data to the battery monitor though. Should I just route the negative line from the battery through the shunt, to the bus bar?

The DC-DC Charge controller is this. It uses power from my alternator and solar to charge the battery.

 

[John Frum]

The fuse should be the first thing off the battery positive.
Close as possible.

 

[Bribenn]

The fuse should be the first thing off the battery positive.
Close as possible.

the fuse and then the kill switch?

 

[John Frum]

the fuse and then the kill switch?

Yes.
The fuse should be as close as possible to the battery positive to minimize the risk of a short upstream of the fuse which would be a disaster.

 

[John Frum]

As for the origninal problem.
Try opening the charge controller breaker before you disconnect the battery.
See if that addresses your issue.
Should only take a minute, I'll wait.

 

[Bribenn]

As for the origninal problem.
Try opening the charge controller breaker before you disconnect the battery.
See if that addresses your issue.
Should only take a minute, I'll wait.

yes, that seemed to work. Do you know why? Do I need to change something?

 

[John Frum]

The charger was powering the system.
What exact charger is it?

 

[Bribenn]

The charger was powering the system.
What exact charger is it?

I thought that once the kill switch is in the off position, power can't flow through it?
The charger is this.

My battery voltage is not at 11.7 or something and I was getting alarms yesterday, but the victron battery monitor says it's 100% charged. Could I have ruined my batteries?

 

[svetz]

The charger was powering the system.

Nice call! I was suspecting the caps in the inverter, but they'd only last seconds at most! <bows to the master ?>

 

[John Frum]

The kill switch isolates the battery from the rest of the system.
The charger is downstream of the switch and therefore un-affected.

 

[John Frum]

Since that charger has a common negative your drawing does not represent reality.
If you would like us to do a thorough audit of your system please post an actual picture.
If not that is cool to.

 

[Bribenn]

Since that charger has a common negative your drawing does not represent reality.
If you would like us to do a thorough audit of your system please post an actual picture.
If not that is cool to.

it's a bit hard to take a picture of the whole thing, but I will try. one moment...

 

[Bribenn]

 

[LB3]

You’re still feeding the loads directly from your panels and the ‘kill switch’ is acting as a battery isolation switch but isn’t killing your loads.

Install a dual throw switch with one leg cutting off the battery and the other leg killing your loads.

 

[Bribenn]

You’re still feeding the loads directly from your panels and the ‘kill switch’ is acting as a battery isolation switch but isn’t killing your loads.

Install a dual throw switch with one leg cutting off the battery and the other leg killing your loads.

so my solar charger is going up through fuse and then coming out to the other side and feeding my loads? Is there any way to kill all of the power with the pieces I have?

 

[Bribenn]

so my solar charger is going up through fuse and then coming out to the other side and feeding my loads? Is there any way to kill all of the power with the pieces I have?

Also, is the charge controller even charging my batteries? For some reason, my battery voltage is only 11.7 and my inverter alarms and my charge controller signals that there is low voltage when I try to connect loads.

 

[John Frum]

so my solar charger is going up through fuse and then coming out to the other side and feeding my loads? Is there any way to kill all of the power with the pieces I have?

There is a lot of scary stuff.
And thats only the stuff I can see.
The scariest thing I can see are those breakers.
Cheap "knockoff" breakers will trip to early if you are lucky and weld shut if you are not.
I will draw you something later when my chores are done.

 

[snoobler]

The charger was powering the system.
What exact charger is it?

That's where I was headed.

I thought that once the kill switch is in the off position, power can't flow through it?
The charger is this.

My battery voltage is not at 11.7 or something and I was getting alarms yesterday, but the victron battery monitor says it's 100% charged. Could I have ruined my batteries?

It helps to think of the battery as a "load" on the charge controller.

By isolating the battery, you're only removing part of the load, so the charge controller still sees the loads as part of it "charging" duties. The removal of the battery from the "loads" likely creates an imbalance where the charge controller shuts off after a short period of running either due to a change in load or solar insufficient to maintain voltage.

Your Victron battery monitor is completely useless with the extra (-) cable bypassing it. Likely less than half the current going in or out of the battery is passing through the shunt.