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Breaker vs Battery disconnect switch

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MountainBiker

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I have both a breaker and battery disconnect switch between my DD - DC charger output and the main bus bar. My question is, do I really need the disconnect or is it redundant given I can shut off the flow from the charger by tripping the breaker switch?
 

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MountainBiker said:
I have both a breaker and battery disconnect switch between my DD - DC charger output and the main bus bar. My question is, do I really need the disconnect or is it redundant given I can shut off the flow from the charger by tripping the breaker switch?
Click to expand...

Probably.

A high quality breaker can be trusted to be used infrequently as a disconnect. That looks like a cheap ebay breaker. I wouldn't trust it for anything.

It is best practice to have a manual disconnect.
 
sunshine_eggo said:
Probably.

A high quality breaker can be trusted to be used infrequently as a disconnect. That looks like a cheap ebay breaker. I wouldn't trust it for anything.

It is best practice to have a manual disconnect.
Click to expand...
Ok! So then I need better breakers than I have i suppose. Disconnecting would not be a frequent thing...it would be something I can use to isolate / turn off a power source so I can do maintenance/ upgrade ect...
 
MountainBiker said:
Ok! So then I need better breakers than I have i suppose. Disconnecting would not be a frequent thing...it would be something I can use to isolate / turn off a power source so I can do maintenance/ upgrade ect...
Click to expand...
For maintenance I use Midnight solar breakers. I have some that are turned off once a week when we change campsites. They have been in service since 2012.
Or maybe I just got lucky. Anyways just ordered 8 more for a off grid set up.
 
scrubjaysnest said:
For maintenance I use Midnight solar breakers. I have some that are turned off once a week when we change campsites. They have been in service since 2012.
Or maybe I just got lucky. Anyways just ordered 8 more for a off grid set up.
Click to expand...
Thx! This is what I am hoping to do. I can use the one disconnect I already have but if my breaker can do the same thing....I would rather not use my limited wall space using more disconnects.
 
What voltage is this system?

What’s the battery source?

On smaller stuff I like fuses for OCP, they are cheap.
 
My system is 12v. There are 3 sources of power

1. solar through a renogy 30a charge controller.
2. car alternator through a renogy 40a DC-DC charger
3. shore power through a Power Queen 20a AC-DC charger.

My batteries are 12v Lithium's @ 100ah.

Sorry for my ignorance. What is OCP?
 
Last edited:
MountainBiker said:
My system is 12v. There are 3 sources of power

1. solar through a renogy 30a charge controller.
2. car alternator through a renogy 40a DC-DC charger
3. shore power through a Power Queen 20a AC-DC charger.

My batteries are 12v Lithium's @ 100ah.

Sorry for my ignorance. What is OCP?
Click to expand...
Over Current Protection.
 
I have been looking for a automatic or remote battery switch that can handle 48v batteries. I would love to give BEP MARINE 720-MDO motorized switch. The motor runs on 12V but capable of switching 500A at 48V. This would make a great emergency shutdown to an existing system. For around US$200 I haven't pulled the trigger yet.

SPECIFICATIONS:• Continuous rating: 500 Amps DC - minimum 2x95mm²(2x 3/0) cables• Intermittent rating: 700 Amps DC - minimum 2x95mm²(2x 3/0) cables• Cranking rating: 2500 Amps DC - minimum 2x95mm²(2x 3/0) cables• Maximum Voltage: 32 Volts DC (for motor/PCB supply)50 Volts DC (switch contacts – note motor/PCB supply requires 12/24 volts)
 
From my *research* using the breaker as a disconnect can cause issues with arcing and can catch fire. Mind you, this is all from watching youtube vids when I was getting started in my solar journey. I have my solar disconnect near the right off the panels on my carport that I use to shut off the panels, then I flip the breaker to off that is mounted right before the input into my inverter. Yeah, it is a pain to walk 40' to shut them off first, but I rather know that the entire line is not sending 400v DC live right where I am working when fooling with the system.
 
Timmaahhh said:
From my *research* using the breaker as a disconnect can cause issues with arcing and can catch fire. Mind you, this is all from watching youtube vids when I was getting started in my solar journey. I have my solar disconnect near the right off the panels on my carport that I use to shut off the panels, then I flip the breaker to off that is mounted right before the input into my inverter. Yeah, it is a pain to walk 40' to shut them off first, but I rather know that the entire line is not sending 400v DC live right where I am working when fooling with the system.
Click to expand...
Fuse inline with the Disconnect at the panel and a disconnect in the area of the MPPT. Fuse protects the wire from the power source and double disconnect insures I won't get 'blasted'. The MPPT from inverter from the EG4 puts out voltage without the solar. Have to protect you from both directions.
 
BarracudaBob said:
I have been looking for a automatic or remote battery switch that can handle 48v batteries. I would love to give BEP MARINE 720-MDO motorized switch. The motor runs on 12V but capable of switching 500A at 48V. This would make a great emergency shutdown to an existing system. For around US$200 I haven't pulled the trigger yet.
Click to expand...

I never knew they made such a thing.

I have a couple of Kilovac solenoids to isolate gear in my system ... though may be overkill in this situation.

12-900V contact rating and 500A switching ... and 48-72V coil with economiser to reduce hold in current. The contacts are in a sealed environment containing nitrogen. You can get 12 and 24V coil versions as well.

https://www.aliexpress.com/item/1005005518466976.html?spm=a2g0o.detail.0.0.eac9rpncrpncDB&mp=1
 
rogerdw said:
I never knew they made such a thing.

I have a couple of Kilovac solenoids to isolate gear in my system ... though may be overkill in this situation.

12-900V contact rating and 500A switching ... and 48-72V coil with economiser to reduce hold in current. The contacts are in a sealed environment containing nitrogen. You can get 12 and 24V coil versions as well.

https://www.aliexpress.com/item/1005005518466976.html?spm=a2g0o.detail.0.0.eac9rpncrpncDB&mp=1
Click to expand...
I like it, rather rotary switch and no hold current but tis is fare more economical

1-1618002-1 EV200ADANA High Voltage Relay Coil 48-72V For TE New Energy Vehicle
www.ebay.com

1-1618002-1 EV200ADANA High Voltage Relay Coil 48-72V For TE New Energy Vehicle | eBay

Product Type : Relay. - Power Switching : Yes. Usually it costs about 30USD-50USD.
www.ebay.com
 
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