Outback upgrade versus total rebuild to all Victron, or other

[kcbuild]

If DC negative is already grounded, that means your AC and DC grounds are the same, so it technically shouldn't matter.

The preference is to run a ground wire from the chassis screw to the AC ground that is connected to an earth rod.



Everything above the ground (dirt) bonded.
Everything below the ground (dirt) bonded.
ONE connection from above ground to below.

Worth watching link #7 in my signature from the timestamp linked.

No ground rods at array. Run a ground conductor from the panel frame along with the PV wires back to the system ground.



With a 2P array, you don't need any fusing or breakers to protect the wire. PV wire should be sized for 1.25X array Isc and fused for 1.25X that value if your array is 3P or more. In a single string or 2P, the panels themselves will act as fuses before the panel wires will burn up. In 3P or greater arrays, a short circuit of two strings through a 3rd string (or more) could exceed the panel wire rating and cause the panel wire to catch fire.

I relax the fine strand requirement on the PV input of the MPPT because it's lower current than the output, but it is very important to properly secure the wire in the terminals.

100A fine strand wire from MPPT to battery with 125A fuse/breaker.



Probably not all cells within the battery, but probably the battery temperature in 2 locations.



From the Lynx Smart BMS manual:

Low temperature or high cell voltage cut off

If a cell voltage becomes too high and has reached the high cell voltage threshold (3.75V hard coded in battery), or if the low temperature threshold (adjustable in battery) has been reached, the ATC contact opens and will turn off all chargers. If the Lynx Smart BMS is connected to a GX device, DVCC compatible chargers that are connected to the same GX device will be turned off as well.


It should be pretty straightforward provided you configure it properly and have both the Lynx and the MPPT connected to the Cerbo with DVCC enabled.

Thanks Sunshine-eggo

Unfortunately the ground/rods situation is a bit of a mess, and as noted, I will need to do some clean up to get to your link#7 ideal (which I have read several times-very helpful). The original Outback install included separate ground buses, wires AND rods on the AC side AND the DC side (ie separate grounding rods placed for AC and DC at the inverter shed location). These in addition to the main AC panel ground system/rods at the cabin itself. I think this was common at the time and within Outback specs. This will need to be simplified eventually tying everything together at a single ground rod site (likely with the main panel at the cabin). I am double checking everything and drawing out a wiring diagram to make sure I have everything accounted for. I don't want to leave something ungrounded or with undersized ground wiring. The one place the original installer (2007) did not place extraneous ground rods was at the solar panel frames, instead taking the frames' ground wire along with the PV out lines 150 ft and tying it into the DC neg ground at the outback DC panel at the inverter/battery shed. To make matters more complicated now the installer of the new solar panels this summer (2024) insisted on adding yet an additional ground rod at the solar panels 'cus that's how he does it. I even tried to invoke Mike Holt, but it was easier to just let the installer proceed with the new ground rod than argue, and disconnecting that rod at least will be straightforward. It just goes to show how confused this whole issue is even in 2024 and even for professional installers.

 

[sunshine_eggo]

If all your rods are bonded to each other, that's fine.

Find a different installer.

 

[kcbuild]

If all your rods are bonded to each other, that's fine.

Find a different installer.

Unfortunately all the rods were never bonded together underground at initial installation and getting them them bonded together underground when they are spread 150ft apart is not so easy, especially in our soil conditions and on a small island without ferry service (ie getting equipment/trenchers and workers to the island is a challenge). That is why I am considering trying to minimize the number/sites of rods as much as possible. I may ask for input there when I have drawings available.

For similar reasons, getting installers to come out to the island is also a challenge. That, and just a general interest in learning new ideas and skills, is why I tend to tilt DIY when possible. Input from you and others on this and other forums helps make this possible.

 

[chrisski]

Unfortunately all the rods were never bonded together underground at initial installation and getting them them bonded together underground when they are spread 150ft apart is not so easy, especially in our soil conditions and on a small island without ferry service (ie getting equipment/trenchers and workers to the island is a challenge). That is why I am considering trying to minimize the number/sites of rods as much as possible. I may ask for input there when I have drawings available.

For similar reasons, getting installers to come out to the island is also a challenge. That, and just a general interest in learning new ideas and skills, is why I tend to tilt DIY when possible. Input from you and others on this and other forums helps make this possible.

Any update? Sticking with Outback or going Victron?

My RV is Victron and house Outback

 

[kcbuild]

Any update? Sticking with Outback or going Victron?

My RV is Victron and house Outback

Probably going with all Victron but have not completely decided yet. Have been hoping the new owners of Outback would have reconstituted a new, viable entity by now, but still absolutely no post-EnerSys information on the Outback website and only scant information echoing around on the Outback user forum. If I were dependent on the hardware only, I would still consider sticking with Outback (for the inverter only) given that a replacement (or upgrade) would be a one-day swap out project. My 20y/o VFX is still humming along; I would just buy a VFXR and keep the old unit for back up. Unfortunately my site is remote, part-time use, and it is very useful to be able to control the inverter On/Off remotely. That means I would be relying on the new owners to keep Optics-RE up and running, and based on what I have (not) seen so far, I have no confidence that Optics will be around for the long haul. Which brings me back to Victron but, unlike swapping the Outback MX80 for a Victron MPPT as discussed in the thread above (and which went very well with input from sunshine_eggo), changing over to a Victron inverter will be a much bigger project since the Outback mounting panel and wiring boxes would all have to be taken down to free up real estate before the new build could even start. Not to mention all the possible Victron choices...

 

[chrisski]

Outback has been quiet, but they are answering the support phones again and at the California solar show they did produce a pamphlet about a new closed loop lithium battery, but nothing has made it to their website.

As a user of both, Victron is easier, more intuitive, and more choices, but lacks a grid tied certification, so I could not use that for my house.

Good luck on the build.