AC DC circuit breaker confusion

Rogli

New Member
Joined
May 21, 2021
Messages
20
I have a 12v 280AH lead-acid tall tubular deep cycle batter and connected to the 12v 2500w (surge up to 5000w but rated actual power is 2500w) inverter. I want to install a circuit breaker between battery and the inverter.

One shop suggested me a 80A breaker which seems to be AC-DC (picture attached). My concern is that if I install that beaker, I can only take (12 v *80 A) power from the inverter which is capable of 2500w. Any advice here? Should I go up in amperage of the DC breaker but how much actually?
 

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chrisski

Solar Boondocker
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Aug 14, 2020
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2,685
Here is a link to Midnite SOlar’s breakers:


THere are DC only breakers there designed for higher voltage PV. The higher amperage ones like the 250 amp breakers are rated for 50,000 AIC and 125 volts or more.

I dI’d not design my two systems with breakers for the batteries, but that’s before I saw these. I don’t know if these C/B are rated for main battery protection, but to me it looks like they may be.

I use ANL or Class T fuses.

I don’t think a2500 watt inverter on 12 volts is a good idea. You will end up having some really thick cable. 4/0 or thicker.
 

Short_Shot

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Jul 13, 2021
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A 2500w inverter will pull as much as 250 amps from that battery at full load after losses.

You won't even be remotely close to running that inverter off an 80a breaker, and that doesn't even begin to factor in surge current capacity of said breaker.

And definitely make sure you have adequate size wires. You're talking about big stuff here.
 

740GLE

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Apr 30, 2021
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637
We’ll, he never stated his load intending to run.

Maybe he had it kicking around or got it cheap someplace. 80a of just lights and cell phone charging is more than adequate, I’d still want to get nice big cables for it though.

Also if he were to be pushing that inverter, his battery is also undersized IMO, so I’d more concerned with his needs.
 

macheung

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May 31, 2021
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If you are running 2500W, stop may want to consider using a 24V setup to reduce the need for super thick wires that can carry 250A.
 

Short_Shot

Photon Sorcerer
Joined
Jul 13, 2021
Messages
1,820
We’ll, he never stated his load intending to run.

Maybe he had it kicking around or got it cheap someplace. 80a of just lights and cell phone charging is more than adequate, I’d still want to get nice big cables for it though.

Also if he were to be pushing that inverter, his battery is also undersized IMO, so I’d more concerned with his needs.
Except the post literally asked about it limiting the inverter.

Definitely too small a battery though.
 
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