I'm building a system for my RV and decided to use the Samlex EVO-4024 and the SBMS0. Got the EVO and waiting on the BMS and the batteries, so I decided to set up a test rig to figure out the best way to have the BMS control the EVO. I connected some old batteries for testing, and in place of the BMS I set up 2 toggle switches to simulate the Enable Charge and Enable Drain signals from the BMS.
The exact behavior of the EVO is not documented well, despite the excellent manual. And like most inverter/chargers, support for BMS control is poor. The EVO has a single "disable input" that you can wire the BMS charge and invert signals to, but this just freezes it in whatever mode it is currently in.
However, I managed to come up with a way to wire things that I believe works perfectly. I tested all combinations of disabling charging or inverting, and plugging and unplugging AC power, and it always seemed to do the right thing. Took quite a while to figure out so I am posting it below. It takes advantage of the EVO's status relay, so that the disable charge signal only gets to the EVO if it is in charge mode. You will only need to add a Normally Closed signal relay, or an N.C. SSR (I'm looking at using an IXYS CPC1333G with a resistor).
One advantage of this scheme over others that control the AC input is that you don't need a large power relay, and you don't lose pass-thru AC power (and switch to inverting) if charging is disabled.
Posting here for others. I won't be able to build the actual system till the rest of the parts come in next month. Any comments, let me know.
The exact behavior of the EVO is not documented well, despite the excellent manual. And like most inverter/chargers, support for BMS control is poor. The EVO has a single "disable input" that you can wire the BMS charge and invert signals to, but this just freezes it in whatever mode it is currently in.
However, I managed to come up with a way to wire things that I believe works perfectly. I tested all combinations of disabling charging or inverting, and plugging and unplugging AC power, and it always seemed to do the right thing. Took quite a while to figure out so I am posting it below. It takes advantage of the EVO's status relay, so that the disable charge signal only gets to the EVO if it is in charge mode. You will only need to add a Normally Closed signal relay, or an N.C. SSR (I'm looking at using an IXYS CPC1333G with a resistor).
One advantage of this scheme over others that control the AC input is that you don't need a large power relay, and you don't lose pass-thru AC power (and switch to inverting) if charging is disabled.
Posting here for others. I won't be able to build the actual system till the rest of the parts come in next month. Any comments, let me know.