Buy two new efficient top load freezers with the capacity you need is probably the best answer.
Trying to build solar/battery/inverter to power inefficient old appliances is usually never the best path.
Trying to be cheap.
I use SmartWool fireproof material good to 2100F.
They make a paper and a board style - I use the paper between cells and the board style under the cells.
https://www.amazon.com/Lynn-Manufacturing-Temperature-Superwool-Furnaces/dp/B077VRS14X
This will run fine off a 3000W inverter if a soft-start is installed.
Look up MicroAir and you likely need the EasyStart 364. The challenge will be to wire it into that MiniSplit as maybe not directions for that model. The guys at MicroAir offer excellent support and likely can help.
I'm...
Hold off on a CerboGX right now as the next gen model that fixes a bunch of issues is about to release. The 2.90 beta firmware contains support for it.
Also a new 7" display is coming.
The issue is these reducing ferrules limit amp capacity to the size of the ferrule reduced side.
If it's a long run you likely get lower resistance using the bigger wire and the ferrule versus a smaller gauge the size of the reduced side of the ferrule. But for a short run likely not worth it.
Interesting that 3.0V to 2.5V is ~10% capacity in your case. My experience with the 280's is that 3.0V to 2.5V is under 2% of capacity.
I wonder if Docan has cells with "weak knees" that explains the much lower price point?
You can get elements but the better way is to use something like this setup. A small electric hot water tank so the dump load heats the tank and then that tank would feed into your gas unit.
I did find that you can get this small hot water tank setup he used in the 120VAC version from Home Depot.
The problem with the OEM alternators is the rating is somewhat fictitious. For example yea it can do the 140A it is rated at redline after the vehicle has sat overnight in a cold environment. But as soon as up to engine bay temps the OEM models need pretty significant derating; as well as for...
The REC ABMS manual has a good description on the canbus setup with the Venus device and specifically the Cerebo. Follow that and let us know if you run into any issues. It covers the required DVCC settings and canbus settings.
I've never seen this part be too difficult to get running.
A mechanical relay or contactor will only be good for a limited amount of cycles; and that # goes down the higher the load it's switching.
So a couple things:
1) Make sure you are not overly frequently cycling the relay -- some cheap control systems will do this. I had a heat controller that...
https://www.sterling-power-usa.com/library/B2B120%20sheet.pdf
The 120A and 180A are just starting to ship, the 60A has been out for awhile. Give them a call to order. I've not seen the 120A/180A listed with any of the online resellers yet.
Supposedly high current 12/24 units coming as well.