hwy17's Orion battery build

[spitfire6]

Drift I'm gonna have to learn as I go. I think it's gonna be a while of not trusting my SOC calculation since you're basically designing the calculation yourself. Maybe @Ampster has drift setting advice.

Hi,
I suspect you have a current transformer fitted to the Orion.
The Orion Coulomb counts to calculate SOC. A very good method but errors can add up so drift points & times are available so you can use the non-accurate voltage vs SOC to drift the SOC up/down AKA reset the SOC. it is a forced override of the accurate coulomb counting. I would think carefully before adjusting the curve.
Cheers,
Iain.

 

[spitfire6]

Yeah I have some canbus messages that I might be able to get to shutdown my inverter, but otherwise the only option and the only currently enabled option is for contactors to open. I'm relying on my high DCL and CCL only to open the contactors in an extreme fault scenario, if the 150 amp fuse has somehow not already blown.

Contactors also react to high and low cell voltages of course. Also expecting those to never have to open in normal operating conditions.

I'm gonna keep working with 3.437 to try it out, it's kind of my pet project to trial single voltage charging in home storage applications - absorb and float and balance at 55v even.

I probably won't be re arranging since my case is so hard to work in. Luckily 10 is already in a more accessible position.

Do you have any advice on finding resistance factors for the EVE 304's? I'm a bit lost on that, and just relying on my uncalibrated figures as a delta indicator to point out the odd cells, like 10.

Have you ever looked at Nuvation or FoxBMS? I think I will try Nuvation on my next build. They are a north american commercialized version of FoxBMS.

Hi,
For cell resistances, if Orion is not aware of your cell type, I would look at similar Ahr ratings in their DataBase. I would err on the low side. It's not critical but too high and you will get weak cell errors when there are none,
Cheers,
Iain.

 

[hwy17]

A note here for any future Orion builders reading. I missed a key potential signaling mechanism which is that my XW inverter accepts a basic open closed switch remote power enable signal. I.e. you could wire the two control pins to a light switch and the light switch would enable or disable the inverter.

This would be a far preferable shutdown mechanism compared to opening the load contactor. Eventually I will go back now and wire a relay to one of the Orion MPO's connected to the inverter on off, and have that relay open when low cell hits a threshold slightly above the threshold that opens the discharge contactor. E.g. turn off inverter if a cell hits 2.6 and open contactor at 2.5 to hopefully avoid the contactor opening under load.

Graceful recovery and automatic restart from a low battery condition might even be possible this way. The Rosie accepts remote power off relay as well. I don't know if it is common in AIO's or other inverters.