Can a Fuse be too big?

[heirloom hamlet]

I am about to get the 280aH cells to make my 24v batteries with, and I ordered the marine fuse block and some fuses.
My question is, is it bad possible or bad to put a larger fuse on your system than is necessary?
I have four separate arrays and systems using 80a/60a MPPT All-in-one units. One system will be fed by (2250w) 3S3P 24v poly panels and charging two 24v 280aH LiFePO⁴ batteries. I got a 300a fuse for it.
The other two will be paired with (1500w) 3S2P 24v poly panels each and one 24v 280aH LiFePO⁴ batteries, and I ordered 200a fuses for them.
I've done my research and I know these fuses are a great fuse option and are necessary. My question is, can the fuses be too large for your system and either hurt it or do no good?

 

[John Frum]

My question is, is it bad possible or bad to put a larger fuse on your system than is necessary?

Yes.
The fuse's primary job is protect the wire.

I've done my research and I know these fuses are a great fuse option and are necessary. My question is, can the fuses be too large for your system and either hurt it or do no good?

Yes.

 

[heirloom hamlet]

Yes.
The fuse's primary job is protect the wire.



Yes.

Thanks. Do you know what the criteria is for determining what size fuse you need? What specs your looking at on your system?

 

[John Frum]

Circuit Wizard - Blue Sea Systems

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

Part 2: Select a Fuse and Fuse Holder For Your DC Product Installation - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

 

[John Frum]

Generally the system voltage and then the inverter continuous load determine the overall scale of the system.
Unless you have a particularly large dc load to account for.
What system voltage and what is your inverter's continuous load?

 

[heirloom hamlet]

Thank you.

 

[offgriddle]

Yes.

 

[SolarQueen]

The fuse between the charge controller and battery bank should be 25% higher than the controller rating. For the 60A controller, you need an 80A fuse. For the 80A charge controller, you need 100A fuse. The wire should be big enough to handle the 80A and 100A. If you have too big of a fuse, and not big enough wire, the wire then acts as the fuse and you will have a fire on your hands.

 

[heirloom hamlet]

The fuse between the charge controller and battery bank should be 25% higher than the controller rating. For the 60A controller, you need an 80A fuse. For the 80A charge controller, you need 100A fuse. The wire should be big enough to handle the 80A and 100A. If you have too big of a fuse, and not big enough wire, the wire then acts as the fuse and you will have a fire on your hands.

Thanks for that.

 

[Ampster]

Generally the system voltage and then the inverter continuous load determine the overall scale of the system.

The fuse between the charge controller and battery bank should be 25% higher than the controller rating.

To tie these two comments together the NEMA rule is that for continuous loads the 125% rule should be applied. Conversely, a continuous load should not exceed 80% of the circuit breaker or fuse. You can get at it from either end.
Most solar and inverter loads are considered continuous and it is a good rule to use for safety purposes anyhow.