question

liam-tuvey avatar image
liam-tuvey asked

Smart shut as DC meter for DVCC - correct placement

I'm wanting to use a Smart Shunt as a DC meter instead of a battery monitor. (My BMS is providing battery monitoring) My goal is to use the DVCC features of the Cerbo GX to be kind to my battery, however I want to increase the charge current when I have a high DC load attached (solar dump load into hot water tank)


My understanding is that if I configure the Smart shunt as a DC meter the DVCC will then factor in any DC loads and increase the current charge limit. (CCL) - For example, charge current set to 25A as requested by BMS, but there is a 25a DC load, CCL will be set to 50A)


I want to know if I need to reposition my shunt in my circuit for it to perform this function correctly.

I have a relatively simple setup in a campervan:

Lifepo4 battery > lynx distributer as a busbar > Smart Shunt on the negative between battery and lynx.

Solar MPPT, Orion Smart DC2DC, Multiplus II, & DC loads all connected to the lynx busbar.


My question!

Should I move the Shunt to only be on the DC load negative or is it ok for it to remain on the main battery negative?


Obviously the Cerbo can only see and control the multiplus and mppt sources, the Orion is not monitored / controlled. I cant work out what will the DVCC will do if there is input from both the Orion and the solar while battery is full and dump load is on. e.g. What will happen if I'm driving with a full battery and have the dump load on? Will the DVCC compensate and allow the solar to dump or will it reduce the current.


Hope this makes sense, appreciate anyones thoughts before I go rewiring things!


cerbo gxSmartShuntDVCCdc meter
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2 Answers
hjohnson avatar image
hjohnson answered ·

In this situation, I think you want to have the smart shunt just measuring your DC load, not your charging source. This basically means that you need to split your DC system in two, one for your DC loads (including the dump load into the hot water tank) and the other with your inverter/charger, or MPPTs, or whatever your charging source is.

On my boat, I'm building it out with the Lynx Distributor connected to my MultiPlus, the alternator, the Battery (through the BMS), and my solar. In turn, all my DC loads are on a separate fuse block, with the negative for the DC loads run through a separate smart shunt.

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liam-tuvey avatar image
liam-tuvey answered ·

Thanks that's helpful, I suspected as much. Some rewiring to do!

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