question

saku avatar image
saku asked

BlueSolar MPPT 100/30 deep discharge

I bought a BlueSolar MPPT 100/30, and would like to implement a deep discharge protection for my lead batteries. Thought, this is a standard issue, and there should be an output which I can use to cut a relay on the 230V output of my inverter. All relevant consumers are connected there anyway. But it seems, it's not that easy.

First Idea was using the VE-direct TX cable, but I guess I would not be able to use the bluetooth dongle in this case. Thought it would be a good idea not to buy the SmartSolar, because the system is inside a steel cabinet 20m outside the cottage. But I guess, if I use the TX pin, the dongle won't work, right?

Second Idea was the battery protection, but it says, I should not connect an inverter as the protection device would get damaged (Inverter is only 600W actually). So I'd use a 65A MOSFET to switch a ~10mA relay now? And will it then use the advanced Victron battery lifetime function?

Third Idea: Switch it for a SmartSolar and use the TX pin? Actually thought about installing it tomorrow...

Fourth Idea: The SmartSolar MPPT 100/20, which for some reason comes with an integrated load output. But then I'd need two of them because I have two 400W panels.

AAAh!

Any suggestions?

Battery Protect
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

4 Answers
mvas avatar image
mvas answered ·

Victron sells a Battery Protect device to prevent under-voltage. This is exactly what you need. Separation of duties ... The Solar Charge Controller is responsible for charging the battery bank, and to prevent over-voltage. The inverter is responsible for discharging the battery bank, and to prevent under-voltage. I do not understand why you think it is the Solar Charger Controller's responsibility to stop the inverter from going below under-voltage? Have you contacted your local Victron Dealer for design assistance?

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

klim8skeptic avatar image
klim8skeptic answered ·

@saku ebay is full of low voltage disconnect modules. All of unknown quality / accuracy and unknown current consumption when active (you dont want your lvco to further drain your batteries).

If you looking at a more thorough system, you could use the relay in the BMV series battery monitors to act as a lvco.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

saku avatar image
saku answered ·

Well, as I wrote, the SmartSolar MPPT 100/20 does come with a load output, which will be deactivated when battery voltage is too low. Also, a Steca charge controller I have is able to do that. And from my understanding It would be wise to have all te battery related functions in one device.

The smallest BMV system still seems far to big being rated for 500A, and it costs as much as the charge controller itself.

Think, I might keep the Steca installed in parallel until I implemented another solution.

Maybe it's possible to get the shutdown command from the victron's VE.direct with an Arduino?

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Michelle Konzack avatar image
Michelle Konzack answered ·

Why not setup your Inverter to shutdown at low voltage?

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.