Using battery breakers with lower rating than recommended

[air_keng]

Let's say a 5kW hybrid inverter with 5500 pv array, max charge/discharge of the battery is 120A, and the recommended breaker from the inverter to the battery is 150A. Wire used is 2AWG. Unfortunately, the only DC breaker available is for 63A. What are the consequences of using a 63a breaker for this set up?

 

[SparkyJJO]

Easy. You're limiting your 5kW inverter to half its rated output because any higher and you'll pop the breaker.

 

[air_keng]

Easy. You're limiting your 5kW inverter to half its rated output because any higher and you'll pop the breaker.

Noted. But while I wait for a higher amp breaker, is it okay to use 63a and probably set charge/discharge rates to 60A to prevent tripping? Will there be any negative effects on any part of the system?

 

[SparkyJJO]

No just limited capacity and potential of nuisance trips.

 

[air_keng]

No just limited capacity and potential of nuisance trips.

Thank you!

 

[DIYrich]

I would set to 80% of the breaker to avoid wearing out the breaker. Circuits are designed for 80% continous use.

 

[air_keng]

I would set to 80% of the breaker to avoid wearing out the breaker. Circuits are designed for 80% continous use.

I see. Now I understand why they recommend a 150a breaker for the 120a charge/discharge. I'll keep this in mind. Thank you!

 

[Brucey]

Some DC breakers are fully rated, i.e Midnite/Carling/CBI, designed for many cycles. Many others are not and may fail if used repeatedly.

 

[Ampster]

My inverter runs at a third or half of its capacity most of the time because I don't have the loads. No damage in years of use

 

[air_keng]

Finally got my hands on 160a MCCB's for the battery. I'll take note of your inputs and suggestions. Thanks!