question

David avatar image

BYD BMV settings

Hi All

Can someone point me to the BMV settings for a BYD install? Our off-grid installers can work out most settings such as Peukert component, Ah capaicty, charge voltage but some of the other settings are a bit more difficult. We've looked in the Victron/BYD guide and detailed guide but are reaching out for some help

David

BYD
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2 Answers
Anil Ghatikar avatar image
Anil Ghatikar answered ·

In general, BYD should be used with CCGX /Venus GX with Canbus connection so in my opinion, BMV is redundant as the BYD information is available in VRM

Some users are using BMV only for smaller currents ( less than 5 amps) as the BYD BMS is inaccurate for low currents

An another thread has some excellent guidelines on setting BMV for Lifepo4 chemistries

https://community.victronenergy.com/questions/10658/multiplus-settings-for-non-victron-lifepo4-batteri.html

replicated below only the relevant part


If a BMV - The charge efficiency setting in the BMV should be set at 98%.

In order to have the synchronisation right the absorbtion voltage is the Vc ( charge threshold ) whilst the tail current should be set at 10%.

The charge voltage setting (Vc) must be close to the absorption voltage and the tail current is not relevant so can be set to the maximal level (10%).

The time for the synchronisation trigger can be shorter the 9 min as the battery should be full after a few minutes..

Peukert factor ( for lithium 1.05 ) and the charge efficiancy (for lithium 0.98

The discharge floor is DOD 50% default, so that can be set to DOD 90% with lithium as thats then the empty indication for the "time to go " and percent age calculation.

Note: it follows from that the batteries must be regularly (at least once every three months charged to at least 4 x 3,4 = 13,6 V in order to balance the cells.

If not fully isolated when not in use be aware of any residual drain like bilge pumps etc otherwise batteries can be damaged from over discharge.

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boekel avatar image
boekel answered ·

If you find the best settings, please also report back here and share so other users can begin with your results.

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