Smartshunt choices

[chilly2]

I'm considering buying a smart shunt.

Why? I currently have 4 x 12v LifePO4 batteries in series for 48v. The HQST 60A charge controller gives me estimates of what it thinks remains based on voltage but I'm not sure how accurate it is. It gives voltage and a percentage SOC, though there is no estimated time remaining. I'd like a better picture of where the battery is at for SOC and time remaining. Having it in an app / available somewhere I can look at historic data is the main desire.

Assuming that reasoning is sound, I've seen there are two Victron options and a knock off by TBD. I can't decide which one to get. I don't mind spending on the Victron, but is there anything else about the IP65 one that makes it better than the regular one as it's the same price? I'm reluctant to try the TBD but included it to get feedback.

- Victron 500A - https://www.amazon.com/dp/B0856PHNLX
- Victron 500A IP65 - https://www.amazon.com/dp/B0BF636VBX
- TBD knock off - https://www.amazon.com/dp/B0BML5D23Z

Advice welcome!

 

[sunshine_eggo]

Why? I currently have 4 x 12v LifePO4 batteries in series for 48v. The HQST 60A charge controller gives me estimates of what it thinks remains based on voltage but I'm not sure how accurate it is.

The value given and the word "accurate" do not exist together in this universe.

It gives voltage and a percentage SOC, though there is no estimated time remaining. I'd like a better picture of where the battery is at for SOC and time remaining. Having it in an app / available somewhere I can look at historic data is the main desire.

IP65 only if you're worried about it getting wet.

Have no idea how the TBD works, but I know the following about the smartshunt:

1) it will log 45 days of battery data viewable in VictronConnect via bluetooth.

2m at 1s interval (RAM only)
2h at 30s interval
1d at 5m interval
45d at 30m interval

2) it will give you a time remaining value based on the discharge floor you set, i.e., if you set a floor of 20%, the time remaining value is how long until you hit 20%.
3) Multiple parameters can be set to improve the accuracy of the battery monitor. Peukert and charge efficiency in particular.

 

[OffGridForGood]

+1 vote Victron Smartshunt (bought and installed spring 2023, love it)

 

[chilly2]

I purchased the non IP65 one and it's up and running. However I can't seem to get the SOC to mean anything on a consistent basis.

- I have 4 x 12.8v 100AH batteries in series. They are balanced within .05v of each other.
- I fully charged until the pack was resting around 54v-ish.
- I set the SOC to 100% & synchronized in the Victron app.

The inverter is configured to cut off at 49.2V and woke up at 51.6V, so off at 10%, SOC on at 20% SOC.

At the end of the evening having for sure used up the 5120w on offer, the voltage was indeed hovering around 49.2V. The inverter shows the DC voltage lower than reported by the shunt, voltmeter or charge controller, but given the power being output it was clearly past the LifePO4 drop off point.

The Smartshunt showed a SOC around 67%.

My settings...

Battery capacity 100Ah
Charged voltage 52.8v
Discharge floor 10%
Tail current 4%
CDT 3m
Peukert exp 1.05
Charge efficiency factor 99%
Current threshold 0.1A

Suggestions welcome!

 

[MisterSandals]

Charged voltage 52.8v

This is 3.3Vpc. Seems very low.

Eyeballing this chart, shows 65%-70% SoC.*

*never use voltage to determine SoC. :*)

 

[chilly2]

This is 3.3Vpc. Seems very low.

Eyeballing this chart, shows 65%-70% SoC.*

*never use voltage to determine SoC. :*)

View attachment 176464

I admit I just went with what the SmartShunt quick start guide [1] said to do, with the extra steps for LiFePO4 batteries.

Section 8 - VictronConnect settings

- Set the battery capacity (done, 100Ah)
- Aux input (not using)
- Charged voltage as per table (48v system voltage, charged voltage setting 52.8v).

Additional for Lithium batteries

- Set the charge efficiency at 99%
- Set the Peukert exponent to 1.05.

Since seeing your comment I did notice something on page 10 of the full manual [2] that says "for lead acid batteries". It gives no guidance if one is using LiFePO4. Does that mean the resting 100% charged voltage for my batteries e.g. 54.4V?

Thanks again for your guidance.

[1] - https://www.victronenergy.com/uploa...k_installation_guide_-_SmartShunt_IP65-en.pdf
[2] - https://www.victronenergy.com/upload/documents/SmartShunt/9172-Manual_BMV_and_SmartShunt-pdf-en.pdf

 

[sunshine_eggo]

If charging with PV, you need to set charged voltage to 0.2V below absorption and tail current to 6%. Setting to 0.2V below float with PV charging can trigger false syncs to 100%.

Settings for LFP with PV charging voltage absorption at 14.2V:




If only charging with AC charger, theng 0.2V below float.

Discharge floor is what generates the "time to go" value.