I might be more help if I knew what batteries you have and what you want to accomplish in terms of loads running off of the batteries. As for the eco mode, if you're running your fridge all of the time, that's more than enough to keep it powered up.
For example, this latest customer wanted to run everything except his 3 A/Cs off of the inverter, so I told him to get the 3000w inverter/charger and 400 ah of Lifepo4 to handle the micro and whatever power he uses overnight for stereo, lights, furnace, etc. He also has massage couches, so that's a bit of a load as well.
A lot of people throw a bunch of batteries at it or tons of solar and it's not really a balanced, integrated system because they spent all of that money and all they can do for $10,000 is run the micro, the same as my customer is doing for less than 1/3 the cost.
I'm no longer recommending 6v batteries to anyone, since LiFePo4 batteries are so cheap and so much better. For example, LFP are about 99% efficient, FLA loses 20% during charging and about 20% during discharge at recommended loads, at higher loads the discharge losses are even worse. FLA batteries also need constant watering, weigh a lot more, take up more space and die within 4 yrs at best, plus they self discharge at about 10% per month if left without a trickle charge. LFP self discharges at about 1%/mo. and doesn't need a trickle charge.
4 x 6v GC batteries gives one about 440Ah, at 50% usable, that's 220 Ah for a cost of about $400 from Sam's club or about $600 for Trojans. A 200 Ah LFP from Amazon is only $700, lasts 15 -25 yrs (depending on how often you use the trailer), has 160 Ah usable at 80% depth of discharge, weighs about 46 lbs as opposed to 252 lbs for GC batteries. 2 of those 200Ah batteries gives 320Ah usable which is roughly equivalent to 6 GC batteries, if you ignore the 40% losses during charging/discharge. LFP also don't sag anywhere near as much as FLA, plus they deliver all of the advertised power even at high current draw, FLAs deliver less power as the current increases.