Shunt settings

[mike2scuba]

Bought a renogy shunt and when you first set it up you fully charge the battery and set the shunt at 100%
Now this would be ok for a lithium battery that could be run to 0% but not for an AGM battery
Was thinking it might be better to set the 100A Battery at a full capacity of 50A so once it got to 12.1V it would show at 0% charge and have the alarm set at 5%
Anyone else set there's up this way

 

[sunshine_eggo]

Nope. This prohibits you from EVER discharging below 50% even in an emergency. If I'm in a situation where I have to go below 50%, that's when I would want the battery monitor to give me an accurate reading instead of "0%".

 

[mike2scuba]

Nope. This prohibits you from EVER discharging below 50% even in an emergency. If I'm in a situation where I have to go below 50%, that's when I would want the battery monitor to give me an accurate reading instead of "0%".

Maybe a good compromise at 70A so it shows empty at that range and a warning at 20A (50%)

Also do the shunts have to be sat within a certain distance of the negative post or can they be put along any length before connecting to a bus bar or any other device. No real mention in the manual

 

[mike2scuba]

Maybe a good compromise at 70A so it shows empty at that range and a warning at 20A (50%)

Also do the shunts have to be sat within a certain distance of the negative post or can they be put along any length before connecting to a bus bar or any other device. No real mention in the manual

 

[mike2scuba]

See above couldn't delete this message

 

[sunshine_eggo]

Maybe a good compromise at 70A so it shows empty at that range and a warning at 20A (50%)

Still bad. You never know the actual SoC of your battery. Additionally, you can kinda use voltage vs. SoC as a sanity check, e.g., if the battery is under a light load, and it's at 70%, if you read a voltage that indicates a little less than 70%, you can be confident the SoC is correct. If you alter the capacity, you'll never be able to correlate the two.

Ultimately, it's your hardware, so do what you want, but you're asking for advice, so I'm giving it. There's little value in making something deliberately inaccurate.

Also do the shunts have to be sat within a certain distance of the negative post or can they be put along any length before connecting to a bus bar or any other device. No real mention in the manual

As close as possible works best, but anywhere convenient provided it's the only thing attached to battery (-) will work. The greater the distance to the (-) will cause your voltage reading to be less accurate when high at high current. Under heavy load, it will be lower. Under high charge, it will read high.

 

[mike2scuba]

Still bad. You never know the actual SoC of your battery. Additionally, you can kinda use voltage vs. SoC as a sanity check, e.g., if the battery is under a light load, and it's at 70%, if you read a voltage that indicates a little less than 70%, you can be confident the SoC is correct. If you alter the capacity, you'll never be able to correlate the two.

Ultimately, it's your hardware, so do what you want, but you're asking for advice, so I'm giving it. There's little value in making something deliberately inaccurate.



As close as possible works best, but anywhere convenient provided it's the only thing attached to battery (-) will work. The greater the distance to the (-) will cause your voltage reading to be less accurate when high at high current. Under heavy load, it will be lower. Under high charge, it will read high.

Many thanks will leave setting at 100A