I am in the process of upgrading my Mercedes Sprinter based RV to provide AC power to allow the use of AC devices, microwave, TVs etc when not connected to shore power.
I will be installing a Multiplus II 3kVA, 2 x 200 Ah LiFePO4 batteries, an Orion XS to handle the charge from the alternator, and a smartshunt. My choice of BMS is the VE.Bus BMS V2, but I am willing to be told otherwise!
The Sprinter has a signal to indicate the alternator is running and this was previously used for a dumb charging solenoid to connect the alternator output to the original AGM batteries. I was intending to use it on the Orion, but while looking at the BMS, the Victron diagram indicates the use of the “Charge Disconnect” output to signal the Orion.
My question is, where/how should I connect the alternator running signal to my set up which essentially mirrors the Victron diagram below, and what configurations should I employ on the Orion and BMS to support this set up.
In attempting to answer my own question, the manual for the Orion XS states that:
The recommended use of the remote on/off input is:
A switch wired between the L-H pins (ON switch level impedance between L-H pins: < 30kΩ)
A switch wired between (input/output) battery positive and H pin (ON switch level > 4V)
A switch wired between the L-pin and (input/output) ground (ON switch level < 6V)
BMS control via the H-pin (e.g. between BMS ATC output and H-pin)
And for the BMS V2
The Charge disconnect output, normally high (equal to battery voltage), must be connected to the H terminal of the charger’s remote on/off connector. At high cell voltage or low temperature, the Charge disconnect output becomes free-floating and pulls the charger’s remote on/off H terminal low (to battery minus), stopping the charge.
The alternator running signal and the charge disconnect are both normally high, but the remote control on the Orion only has a single High input.
What does the team think about using a couple of relays as an AND gate to connect both the running signal and the Charge Disconnect into a single combined signal?
My fall back position is to reuse the original dumb solenoid to only provide alternator connectivity to the Orion when the engine is running, and also to use the Charge disconnect output from the BMS to signal charging or not to the Orion.
One relay, driven by the alternator signal, switching the control line from the BMS to the H pin of the Orion (using NO+C of the relay) will do the trick.
In case the relay is off (alternator off, control line broken) the H pin of the Orion would be free floating and pulled down internally in the Orion, disabling the charging function. With the alternator running the BMS would be in control of the H pin, enabling the Orion according to the fill level / temperature of the battery.
