SmartShunt Installation

[Craigmconrad]

I only run it down to about 60% before turning it off. I try never to let the house bank get below 50%.


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That's smart to get the most life out of your batteries. I have my SmartShunt setup with 40% usable ah's (270ah x.4 =108). Even with only 108ah usable, I'm still getting 3+30 hrs on the runtime with A/C. Don't ever expect to come close to using the batteries that way; I just wanted to test the system. Overall, I am pleased with the shunt. In addition to the Garmin, I run an Ipad with Navionics and the Victron app displayed side by side; it works well. Safe cruising!!!

 

[Submariner]

You won’t get 108ah usable running the air conditioning.
The battery amp hour ratings are based on a 20 hour period.

Here’s an example using the Universal factory OEM batteries. 110ah each.
This is taken right off the manufacture spec sheet for these batteries.

20 hours at 5.5 amps = 110ah
10 hours at 10.23 amps = 102.3ah
5 hours at 18.7 amps = 93.5 ah
1 hour at 66 amps = 66 ah.

The faster you pull that current, the quicker the batteries get tired.
Firefly numbers are similar to above. This was primarily why I added a 3rd battery.
The hot water tank is about 66amps.
Divided by 2, each battery must give up 33amps.

Divided by 3 and each battery only gives up 22amps.
Then when I time it with solar putting in 20 amps, each battery only needs to provide 15amps.

 

[S@LTD]

This has been a great read! Thankfully I have not murdered my batteries yet although I know they have been wounded a few times. I added a second solar panel a while back which probably saved my bacon despite bumping the wine cooler, the refrigerator knob when moving things around and leaving the stereo on all night dropping my house bank to 10.5 volts when that has happened. Suffice it to say we have been flying blind and you have convinced me to install a battery monitor which has been ordered.

With all of your specific instructions I feel this project is manageable. When I purchase a bus bar for the negative side and move 7 wires off my house batteries to the bus bar on the load side of the shunt, does this bus bar need to be fused? I saw reference to a bus bar with a 250 amp fuse and not sure how to determine what size fuse I need to order?

With my batteries going on 4 years old I see a purchase in my near future and can see how this monitor is going to help me make a more informed decision. Thank you all for this information!

 

[Submariner]

With all of your specific instructions I feel this project is manageable. When I purchase a bus bar for the negative side and move 7 wires off my house batteries to the bus bar on the load side of the shunt, does this bus bar need to be fused? I saw reference to a bus bar with a 250 amp fuse and not sure how to determine what size fuse I need to order?

Fuses go as close to the beginning of the circuit as possible to protect the wire. This would be on the positive side. A battery monitor is installed on the negative side. You shouldn't need any fuses.

 

[S@LTD]

That helps to clarify. Thanks!

 

[Craigmconrad]

VictronConnect setup and operation questions.

1. During setup, I set the battery capacity to 270ah (3x90ah). The discharge floor to 50%, and the alarm at 50%. The main page displays 100% when fully charged. Is this 100% of 270ah? or 100% of 135ah (discharge floor at 50%)?

2. The reason I'm asking, if it is 100% of 135ah, then the alarm should be set to 0%. I have not gotten below 80% because of solar and cruising.

I think the 100% is based on 270ah and the alarm set at 50% represents half discharge which you don't want to go below. But then why have the discharge floor as a setup input if it's not included in the calculation.

The manual says "This setting is used in “the time to go” calculation and is set at 50% by default for lead acid batteries"
So, I interpret this to mean that the % is based on the full ah of your batteries and your time to go is based on counting down to 50% (discharge floor)

Smart people's thoughts??

Regards,

Craig

 

[Submariner]

Fantastic question!
We just published a video about this very topic on our YouTube channel.

The battery monitor uses 100pct to 0 pct based on the configured capacity.

So if you go below 50pct SOC, it’ll show you 40pct, 30pct… even though you don’t want to see that. Ha!

Because, well, that’s the state of charge of the batteries.

With 270 amp hours at 50 pct discharge you should operate within the following range:

270ah total capacity
100pct -0ah
85pct -40ah
50pct -135ah

That’ll give you about 95ah usable.

Time to go averaging I set to 0 minutes for an instantaneous reading. I’ve found that works best. And it is based on the configured discharge floor.

For setting alarms on the Victron, I have them configured for low voltage, high voltage, etc. but I can not hear the alarm. Literally. I can’t hear it. The frequency of it is outside of my audible range. My wife tells me anytime the alarm is going off.

How to use a battery monitor
https://youtu.be/HDE4XtqQvN0


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