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I want to run 2x MPPTs off one solar panel, 2x Batteries 1x MPPT each.
When the Primary battery is charged and goes into Float mode, I'd like the use a change over relay to change the solar input to the 2nd MPPT thus maintaining this Back up battery. I don't have room for a 2nd Panel.
Is there a way of connection to the VEDirect and "reading the Charge state" then activating the change over relay?
There is no "charged" signal that comes out. The charge status is included in the data stream that comes out of the serial port. If you can decide that, you could use that information to drive a relay.
Another way might be to use a photodiode or something to look at when the float LED comes on and then use that to switch a relay.
Why have a big really to switch the panel over? Why not use the signal to enable / disable the other MPPT?
The easiest of course to to simply wire up the other MPPT with its own solar panel.
EDIT: I now realise that you probably don't have physical space for another panel.
If you have programming skills that would be easy to handle with whitepaper documentation. Take a look on VE.Direkt Protokoll or a little bit more difficult VE.Direkt HEX
https://www.victronenergy.com/support-and-downloads/whitepapers
Hi Brad. If your batts are Pb's, then you'll really be shortchanging' the Primary by not letting it spend some time in float - it won't get fully charged..
Consider another possibility. Just using the 100/20, feed the topup charge to the backup batt using the LOAD terminals on it.
https://www.victronenergy.com/live/victronconnect:mppt-solarchargers See section 4.2 (Maybe Program 8, with a timer). Might need a little fiddling to set the right V's, but a fun challenge for a smart fella.
Of course your panel will now be feeding 2x batts, but having maybe come through most of the Bulk phase with the first, should manage. May well delay reaching Absorb. And you may not want your backup to see Absorb anyway, but that's likely just a V setting when you switch it in, and how much time you leave it there.
Of course the LOAD terminals should be switched out by dusk.
Just thinking aloud now, but worthy of a look?..
There is a simple way to do that : buy a Blue Solar PWM DUO : https://www.victronenergy.fr/upload/documents/Datasheet-BlueSolar-PWM-DUO-Charge-Controller-EN.pdf
It charges up to 2 batteries from one solar field and you can even decide how you split the charge % on each output.
That goes if your solar panel is rated @ 300W or less...
Thanks for feedback and ideas to follow up, I knew the smart Victron community could help
