In case of no grid power- will the battery still be charged from solar?

[greymda]

Genuine question, say there’s an outage and there’s no grid power but we have plenty of solar.
There’s a Victron MPPT, a battery with BMS and all connected to inverter via OpenDtu-onBattery.

Question: will the battery still be charged or when the inverter/DTU sees no grid it disables all the functionality?

Hope my question makes sense.

[genmad]

Yes, the victron will charge the battery.
Open Dtu may be off due to the power outage, this will not matter. The Hoymiles can‘t deliver any energy due to outage.

[greymda]

yes, i was looking at this, but then i’ll loose the connection via cable to opendtu, as the ve.direct port will be occupied by the bt dongle.

[DonJohnLong]

You can use the pre programmed lifepo4 profile, or you can disconnect the blutooth dongle after programming.

[greymda]

i’ll try saving up some money, will do a diy usb ve.direct cable as it seems that i need it for a couple of occasions.

[stegbth]

Hi @genmad ,

currently I'm a bit surprised, about this this answer, seems I haven't understood opendtu on battery completly ;)
According to https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom?do=export_pdf
The battery needs to communicate via canbus (or rs485) with the GX or Venus-Device, which controls on the other side the Victron MPPT.
This task I estimated would be taken by OpenDTU on Battery.
but

1. How does this work, when there is no transmit from opendtu to MPPT?
2. this would also answer the question why this would work without OpenDTU on battery.

br
Thomas

[genmad]

The mppt is a solar battery charger, therefore it handles the battery charging. It can charge non smart batteries as well as smart batteries.

smart batteries communicate back to the mppt and therefore it can charge them according to their wishes. Non smart batteries will be charged accordingly to the settings in the mppt, which are types of batterie and voltages.

Open dtu, by just listening to the mppt, uses the „dumb“ approach for the batterie. Therefore it is important to set up the mppt correctly witch type and voltages.

I hope this answered your question @stegbth

[Manos1966]

that makes sense, thanks! last question: when you say “That’s why it’s important to setup your solar charger properly (especially cutoff voltage)” can you help with a screenshot please? i can’t find this on the Victron’s settings page.

https://github.com/helgeerbe/OpenDTU-OnBattery/wiki/Battery%E2%80%90Tipps#useful-comments-about-pylontech-batteries

[greymda]

i don’t have a pylontech, it’s a diy with jk-bms