Lowering self-consumption on Lynx Shunt + Cerbo GX system

DIY
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1

Hello everyone,
I am currently working on a weather station project that will be deployed in Greenland. To manage the battery system, I have selected several Victron Energy components, but I need some clarification regarding their self-consumption.

The components in question are:

  • Lynx Shunt VE.Can (stated 60mA @ 12V)

  • Lynx Distributor (stated 100mA Max)

  • Cerbo GX (stated 2.8W @ 12V)

The system is designed to power a continuous load of only 2W at 12V. Considering the long polar night and the extremely limited energy resources, I cannot afford high parasitic draws from the monitoring system itself.

I have three specific questions:

  1. What is the typical power consumption of the Lynx Distributor? Is the 100mA figure only when all LEDs are active?

  2. Can I use the Lynx Shunt without a constant connection to the Cerbo GX? I would like to connect it only during the initial setup or for occasional maintenance. Will it still function correctly as a standalone fuse/shunt?

  3. Does the Lynx Shunt consume less power if the VE.Can connection is not used? I don’t need constant remote acces

My system also includes a BatteryProtect BP-65 in series with the load, but I assume its consumption is negligible. I am also disregarding the MPPT consumption for now, as they will only be active when solar power is available.

I must use AGM batteries because of the extreme cold. Keep in mind that if they discharge too much they can permanently freeze. (At the moment I don’t know if I’ll have 65Ah or 80Ah batteries)

I have attached a system diagram for better context.

Thank you in advance for your help!

Greenland
Greenland1920×1239 242 KB

P.S. I know that the system is a bit overpowered for the type of load, but this is a research project that will work all year round, also during the 110 days polar night. At the moment, without the 30W wind turbine, the system can survive for 40 days

2

While thats surely a nice system, i personally think thats alot of extra equipment to power just 2W of load.

Since you have four batteries in parallel, how much capacity did you plan for? At what system voltage?

I guess the Cerbo is mainly used for remote monitoring? Have you considered the new lithium superpacks?

3

In addition to what @chrigu suggested, use the new SuperPack batteries. I don’t think you can get SoC from them remotely, but I’m not 100% sure of that. Regardless, don’t use Lynx Distributors for something this small or don’t connect their PC boards. Definitely don’t use a Lynx Shunt. It’s terribly inaccurate and drifts widely over time. At very low currents it will be even worse. If you need to monitor SoC remotely then use a 300A SmartShunt or batteries with BMS(s) that can communicate their SoC and have internal battery heaters. Note that most inexpensive batteries that claim Victron communications usually have internal shunts that can’t accurately account for very small currents. AGM or SuperCycle batteries might be a better fit for this.

4

I just edited the main message with more information. All the system components, including the load, run at 12V.

Regarding the batteries, I must use AGM batteries for two main reasons:

  • They are more predictable in the extreme cold
  • The nearby shops only sell AGM batteries. At the moment I don’t know if I’ll use the 65Ah or the 80Ah ones

I know that maybe all this equipment will be too much for a normal wheather station, but I’m working in a research institute and they need this type of data all year round, also during the 110 days polar night period. Furthermore the station will serviced only once a year.

During the long night all of the system will be susteined by the batteries and the 30W wind turbine. Without any external power, 4 85Ah batteries, with all the safe measures in place (lower limit to the SoC and a good enclosure), can power the load for 40 days.

The research institute I’m working in is also worried about the battery life cycle, so I implemented all of this system.

5

I’ve seen one Smart Shunt 300A, but I’m not sure I can easily insert it in my system. As I sad in the other comment, I need a sturdy system, because it’ll be out in the wild all year round, being serviced only once a year. I don’t need to control it remotely as it whould consume all my energy

6

Then install it in a stainless steel outdoor enclosure. Use a GlobalLink 520 for sending data to VRM. Use an external cellular antenna mounted to the outside of the box. We do this for several customers with 24x7 but very low power draws for seismic and water gauge data.