The Orion BMS is making me car brained

[hwy17]

And now I'm considering using an auxiliary 12v lead acid battery to power the BMS controls.

When I first read this was an option I dismissed it as a car configuration, but when I saw it again recently I realized it actually eliminates all the headache of how hard it is to effectively fuse the small loads like contactors and relays off the giant 48v bank. I can run it all off basically a car battery and then no one can laugh at me for using automotive fuses! Ok well they can laugh but they can't correct me.

 

[toms]

With the smaller gauge wiring required for contactor coils and display modules, BMS power etc, automotive fuses are fine. (same for BMS sense wires if you fuse them).

If you want to confirm it’s simple to rig a test circuit with a fuse to see for yourself.

On one of my systems i use an AC/DC transformer (wall wart) to power the BMS display. That may be an option for you if your inverter is always on.

 

[hwy17]

Yeah I figured there's some more complexity to the reality of small fuses and wires.

But I have a suitable battery laying around anyway, and a battery tender that I can leave plugged into an outlet on the inverter's output. The more I think about it the more I like it.

 

[Ampster]

And now I'm considering using an auxiliary 12v lead acid battery to power the BMS controls.

I just used a DC to DC converter that comes off my pack at 53 volts and powers my Orion Jr BMS, contactor and other 12 volt peripherals. I agree with the point in the title that it is sometimes hard to get past the EV terms and functionality with Orion. However I have been using it for seven years and it is bullet proof and the voltage and SOC estimates are very acurate compared to my SolArk. The Orion Jr is much simpler and offers connectivity to my SolArk which the bigger unit does not.

 

[hwy17]

I'm enjoying getting pulled into their thinking. It's a refreshing compliment to the solar world.

 

[toms]

But I have a suitable battery laying around anyway, and a battery tender that I can leave plugged into an outlet on the inverter's output. The more I think about it the more I like it.

The advantage of this is if your BMS disconnects the load you will still be able to see the display. I did have this setup for a while, but then i needed the battery for my lawn mower so replaced it with the transformer.

 

[hwy17]

then i needed the battery for my lawn mower

Batteries are known to get poached in my house too!

 

[hwy17]

Extra advantage found: The Orion can zero out it's hall effect sensor calibration on startup, but only if it's on a separate power supply so that the battery bank draw is truly zero.

And the simple LED SOC display accessory from Orion is 12v only.

 

[cinergi]

From my system build parts list (https://diysolarforum.com/members/cinergi.12721/#about) -- fuse holder, fuse, SSR driving a contactor -- all 48v.

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